Auto lockup [Archive] - The 75 and ZT Owners Club Forums

crofts

10th February 2013, 04:23

You can get a good idea by getting the car in top, then slowly decrease speed untill the car changes down. The lock up speed will be slightly faster than it's drop out speed. :)

My diesel locks up at about 50 mph, and drops out at about 45 mph. :)
...

Agree with you James. Mine is also a CDTi & don't know if this is different to the V6 though another member above mentions his.
In general I can coax it into top around 48mph and mine also comes out at 45 or so.
Wish T4 could enable lock-in at 30. There's no strain on the engine at this speed and it would be so much more economical around town. Wonder, for example if there is a solenoid for this, perhaps (or another way) :shrug:

Ford Prefect

22nd February 2013, 13:37

Hmm, interesting, I wonder if there are any issues with fitting a CDT gearbox ECU to a 2.5 V6.. apart from it changing up earlier that is, might be intereting to try as long as its not going to fry anything! The 2.5 V6 certanly seems to lock up at about 62-65 whihc TBH is insane and I can't see any locgical reason fro this, the 825 would be locked up at about 55 IIRC and returned way better MPG unless it had blown its heads! and the 825 was a larger car, I can't see weight being an issue

SD1too

22nd February 2013, 14:04

I must admit that I am a bit confused by this thread. Are you all discussing torque converter lock up? In everyday driving I can't say that I can detect it at all; its engagement seems to be extremely smooth on my car. Are you sure you're all not feeling an upchange into 5th gear?

Simon

Ford Prefect

22nd February 2013, 14:33

No I am talking about the lockup in 5th.. it is extreamly smooth!, or is some times depends on whats going on, but at about 62-65 in mine the revs slowly but noticeably drop (relativly, under a sencond anyway) its failry ready to drop out as well. I'd hope it was in 5th way bfore reaching that speed!

The reason I want to know is once locked up there will be little or no differance MPG wise compared to the manual, unlocked there are significant losses which are passed on in the way of excessive fuel consumption (compared to a manul). I can't belive that it needs to be as high as it seems to be given the 825 locked up far sooner at 55ish whihc would mean it used much less fuel cruising on A-B roads

Parker

22nd February 2013, 15:51

Mine a 2.5 V6 does the same whilst in 5th once reaching around 65 MPH there is a dip in the revs which is noticeable.

crofts

24th February 2013, 03:19

I am wodering when the auto box on the V6 locks up in top? irritatingly it does not seem to have done so at 50, which will hurt the MPG

Yes, does seem unnecessary as surely the V6 has adequate power to accept changing into 5th, as with the diesel

Ford Prefect

24th February 2013, 20:14

So the next question is.. how do I identify a CDT gearbox ECU? as I think it may be intersting to try one and see what happens, as long as it won't do anything hideous to the geabox itself. There are a few of them on eBay but no more information than the part number, no idication of what car they came from. Once I have the ECU would it just work or di I need to pair it up with anything else?

crofts

25th February 2013, 03:10

Get hold of 'seancar'. He may have an answer and will almost certainly have an ECU at a reasonable price. He also has T4 so will know if programming an auto ECU is necessary.

Ford Prefect

25th February 2013, 07:41

Actually I have had a thought about this.. I wonder if this was done deliberatly to stop the 2.5 V6 auto having better economy than the 2.0 V6?
Anyonw know what speed the 1.8 auto locks up at? this may have a better suited programmme to the CDT (rather perversely) as I'd hope it won't get upset at seeing engine RPM over 4K which I would guess a CDT ECU will

tourer

25th February 2013, 13:48

My CDT auto does not seem dependent on speed to lock up in 5th, but temperature.
Once warmed through it changes up, on low throttle, at 42 mph (true mph as measured by sat-nav).
When the weather is very cold torque convertor may not lock up in 5th until 3 to 4 miles are travelled.
Once warmed up in locks up as soon as it goes into 5th.
Has been this way 8 years since new.

crofts

26th February 2013, 03:24

That's not my experience. I have a clear run (most times) just after leaving my drive. I quickly get it up to 50 and it never fails to drop into 5th, hot or cold. I always lift off accelerator briefly at 50........never fails to drop in. It is very obvious on the rev counter.

I have an idea 1,8's were not fitted with auto but may be wrong. If I am and they change at 50 then I cannot see any justification for a 2.5 to only drop in at 60-65

SD1too

26th February 2013, 11:30

... it never fails to drop into 5th ...
Hello David,

My apologies if I've misunderstood your posting, but they're discussing the operation of torque converter lock-up. Engagement of 5th gear is, as you know, a separate operation. Rather surprisingly, MG Rover says that lock-up is possible in gears 2, 3 & 4 as well as fifth.

When the weather is very cold torque convertor may not lock up in 5th until 3 to 4 miles are travelled. Once warmed up in locks up as soon as it goes into 5th.
MG Rover confirms this:
"To promote engine warm-up at low temperatures, the EAT ECU will inhibit lock-up if the gearbox fluid temperature is below 40 degrees C."

Simon

crofts

27th February 2013, 06:04

Well back to school ! Have just read through all pages re Automatic Transmission (pages 95-98) in my owners manual.
Surprisingly the term 'Lock-Up' is not mentioned in any shape or form.
I checked also under 'cruise control' and 'traction control'
I cannot see a practical purpose of 'lock-up' in 1st,2nd 3rd & 4th.
So I have to ask the question 'What changes to indicate 'lock-up' ?
Nothing to my knowledge changes, or is indicated, after the box drops into 5th, other than, naturally, reduction in revs for a given speed. no clunk, click or change whatsoever. And once in 5th a brief lift off of the accelerator, at any speed, does not produce any effect. So how do you know it is 'locked-up' ? ?
I will be grateful for enlightenment ' I'm flumoxed ! :confused: :shrug:

SD1too

27th February 2013, 06:20

I cannot see a practical purpose of 'lock-up' in 1st,2nd 3rd & 4th.
Not first gear David; just 2nd to 5th as said above! :)
So how do you know it is 'locked-up' ?
Well, in my experience you don't, since any reduction in revs is small and the engagement is softened by a gradual change in hydraulic pressure to the actuator, so there won't be a "clunk". However, folk above say that they can feel it.

There's a brief reference to it in MGR's workshop manual.

Regards,

Simon

wutang

27th February 2013, 09:40

On my v6 lockup seems to occur at about 60mph but if gentle will then hold until 54mph or so.

you should notice lock up once in fifth gear the reves will then drop again by about 300rpm. if you put your foot down again the revs will rise without an actual gear change as the converter un - locks again.

Shortly after I got my car my dad borowed it and when I got it back he comented that the box was super smooth but that the ratio on sixth gear was so close to fifth that there was no point having it!

Richard

kaiser

27th February 2013, 13:04

I will bet a case of beer, that the information regarding the lock-up on all gears except first is incorrect.
Further, in Sport mode, 5th gear is not selected at all (as far as I remember), and lock up is not available, at all!.

The lock up locks the output shaft solid, and there is no torque multiplication at all. That also means that acceleration is direct and poor at low revs.

Anyone with an autobox can go and verify this for themselves.

Ambling along in lock up, the first thing the box does, if you want to accelerate even moderately, is to drop about 400 revs. That is when the box goes out of lock up. Even more acceleration, and it drops a gear, more two and maybe three, depending on input and speed. Each gear change will correspond to more than 1000 revs.

So there is simply no point in the box going into lock up at anything less than about 2000 revs. There simply is hardly any torque available.

James.uk

27th February 2013, 14:01

Kaiser is right. I know that at a certain speed in top gear an auto box will lock to the drive shaft at the same ratio as the manual box of the same make.. All my Jags did it, so did the other auto's I have driven.

Once you stop accelerating in top gear, the auto box can lock up, it wont do it while being driven hard due to excessive pressures in the gearbox. but once you ease off, the pressure equals out and it will lock up. :}

I remember some of this from the time we stripped a few auto boxes when I was an apprentice engineer doing hydraulics innit.. :}
...

kaiser

27th February 2013, 14:08

Of course I'm right.
I'm always right!
:D
And when I'm not right, I am certainly not left!:getmecoat:

SD1too

1st March 2013, 20:10

you should notice lock up once in fifth gear the revs will then drop again by about 300rpm. if you put your foot down again the revs will rise without an actual gear change as the converter un - locks again.
... the first thing the box does, if you want to accelerate even moderately, is to drop about 400 revs. That is when the box goes out of lock up.
.. whilst in 5th once reaching around 65 MPH there is a dip in the revs which is noticeable.
Evening gents,

I've just returned from a couple of days driving on A roads and motorways during which I made a renewed attempt to detect torque converter lock-up. I did notice the reduction in revs described in the above posts, but this seemed to correspond with an upchange from 4th to 5th, as verified by immediately moving the gear selector back to '4' and noting the tachometer reading. I wasn't able to link any reduction in revs irrefutably with torque converter lock-up.

It's worth bearing in mind that at a constant road speed in a high gear (e.g. 5th) the torque converter's impeller speed is relatively low, and so is the turbine speed. A state of equilibrium exists where the inertia of the transmission fluid within the converter contributes greatly to maintaining the steady road speed. It is my understanding that by-passing this fluid coupling with a mechanical connection ("lock-up") is therefore unlikely to result in the dramatic reduction in revs previously suggested. In addition, MG Rover says that the engagement of lock-up is achieved progressively by a gradual change of hydraulic pressure. For all these reasons, I am still unconvinced that we can detect when lock-up is activated or deactivated, particularly if it coincides with an upchange or downchange of gear, which is entirely possible with sophisticated ECU control systems.

Simon

crofts

2nd March 2013, 02:59

Dammit............that answers the next question I was going to ask.......I think.
Reminds me of the saying 'The angle of dangle is equal to the heat of the meat'........don't know why though ! :getmecoat:

kaiser

2nd March 2013, 04:22

Evening gents,

I've just returned from a couple of days driving on A roads and motorways during which I made a renewed attempt to detect torque converter lock-up. I did notice the reduction in revs described in the above posts, but this seemed to correspond with an upchange from 4th to 5th, as verified by immediately moving the gear selector back to '4' and noting the tachometer reading. I wasn't able to link any reduction in revs irrefutably with torque converter lock-up.

It's worth bearing in mind that at a constant road speed in a high gear (e.g. 5th) the torque converter's impeller speed is relatively low, and so is the turbine speed. A state of equilibrium exists where the inertia of the transmission fluid within the converter contributes greatly to maintaining the steady road speed. It is my understanding that by-passing this fluid coupling with a mechanical connection ("lock-up") is therefore unlikely to result in the dramatic reduction in revs previously suggested. In addition, MG Rover says that the engagement of lock-up is achieved progressively by a gradual change of hydraulic pressure. For all these reasons, I am still unconvinced that we can detect when lock-up is activated or deactivated, particularly if it coincides with an upchange or downchange of gear, which is entirely possible with sophisticated ECU control systems.

Simon

It is of course possible that something here does not work as it should.

It could possibly be your box.:getmecoat:

Ford Prefect

2nd March 2013, 16:01

Evening gents,

I've just returned from a couple of days driving on A roads and motorways during which I made a renewed attempt to detect torque converter lock-up. I did notice the reduction in revs described in the above posts, but this seemed to correspond with an upchange from 4th to 5th, as verified by immediately moving the gear selector back to '4' and noting the tachometer reading. I wasn't able to link any reduction in revs irrefutably with torque converter lock-up.

It's worth bearing in mind that at a constant road speed in a high gear (e.g. 5th) the torque converter's impeller speed is relatively low, and so is the turbine speed. A state of equilibrium exists where the inertia of the transmission fluid within the converter contributes greatly to maintaining the steady road speed. It is my understanding that by-passing this fluid coupling with a mechanical connection ("lock-up") is therefore unlikely to result in the dramatic reduction in revs previously suggested. In addition, MG Rover says that the engagement of lock-up is achieved progressively by a gradual change of hydraulic pressure. For all these reasons, I am still unconvinced that we can detect when lock-up is activated or deactivated, particularly if it coincides with an upchange or downchange of gear, which is entirely possible with sophisticated ECU control systems.

Simon

Mine has engaged 5th before it reaches 50! , once it has locked up in 5th the RPM sit at about 2100, you can tell when its locked up by very gently applying a little power then removing it, the revs will rise without a speed increase and then drop if it's not locked up

kaiser

2nd March 2013, 16:06

The logical way to state this would be to say more or less the follwing

If un-locked, a light press/release on the speeder will result in a increase/decrease in engine revs at constant road speed, showing the slip in the torque convertor.
If locked: a light press/release on the speeder gives no change in the engine revs, thus showing the direct, locked linkage of the box.

And this is exactly how it is. Go and try it yourself.

SD1too

2nd March 2013, 16:24

Mine has engaged 5th before it reaches 50! , once it has locked up in 5th the RPM sit at about 2100 ...
There's something odd here Stewart. MG Rover data for the 2.5 litre auto with 215/55 R16 tyres is 27.4 mph per 1,000 rpm in 5th gear. This gives a true 57.5 mph at 2,100 rpm. Your speedo, with its 10% error, should be indicating around 64 mph.

Simon

kaiser

2nd March 2013, 16:35

As far as I remember. Mine does about 130km/h at about 2800 revs.
That would be equal to 47 km/h/1000revs. Or 29mph/1000 revs.
2100 thus would be almost exactly 60mph.

I have timed mine on road markings, and mine shows about 6 to 7% above. 130km/h true (about 140km/h on the clock) is thus safe for 120km/h highways, with a 10% allowance.

Ford Prefect

2nd March 2013, 20:07

There's something odd here Stewart. MG Rover data for the 2.5 litre auto with 215/55 R16 tyres is 27.4 mph per 1,000 rpm in 5th gear. This gives a true 57.5 mph at 2,100 rpm. Your speedo, with its 10% error, should be indicating around 64 mph.

Simon

Not really, the 10% error is not a fixed definate, thats the maximium margin or erro allowed under the EU directive for such things, and is just a maxiumum, as long as it does not show a lower speed, and is no more than 10% fast then its allowed, so theres no requrement.. but it does read between 62 and 65 when it locks up and RPM do seem to be 2100 ish so yeah you are right! 5th seems to engage at near 40 (only know this as I was counting the gear changes tonight!)

SD1too

2nd March 2013, 20:50

Not really, the 10% error is not a fixed definate ...
I was referring to practical tests which I have carried out, not regulations. My speedo over-reads by exactly 10% and I believe that this applies to all 75s and ZTs.

Simon

kaiser

2nd March 2013, 21:19

I was referring to practical tests which I have carried out, not regulations. My speedo over-reads by exactly 10% and I believe that this applies to all 75s and ZTs.

Simon

Simon. Stop believing.
Now you know this is not the case, because I have just told you.
:getmecoat:

SD1too

2nd March 2013, 23:06

Sorry, I should not have strayed from the subject of this thread. Speedo accuracy has been discussed at length before and it became complicated and uncertain. I am very interested in Ford Prefect's discussion about torque converter lock-up so I think we should stick to that before a moderator steps in. :}

Simon

Ford Prefect

3rd March 2013, 07:25

There appear to be 3 gearbox ECU part numbers,

UHC100138
UHC100139
UHC000340

The final one appears to be for the 1.8 turbo, which might be worth a try, depending on when those lock up

SD1too

3rd March 2013, 08:27

Hi Stewart,

The 2.5 V6 uses automatic gearbox ratios and final drive exclusive to that engine. A transmission intended for any of the other engines will affect the gearing and performance of the car, probably detrimentally.

Also, there is no data available about torque converter lock-up. It is almost certainly controlled by the EAT ECU, not the gearbox, so your first step should be to ask the T4 practitioners if there is any facility to reprogramme this feature. Somehow I doubt it.

I'm also surprised that you appear to be considering such drastic modifications to your special and rare 'dealer launch' Rover 75 which, even if effective, will hardly make a dramatic difference to its performance. Or are you just playing devil's advocate? ;) :D

Simon

kaiser

3rd March 2013, 08:30

SD1too

3rd March 2013, 08:34

Borg Warner

3rd March 2013, 10:05

I was referring to practical tests which I have carried out, not regulations. My speedo over-reads by exactly 10% and I believe that this applies to all 75s and ZTs.

Simon

Mine doesn't. Seems quite accurate at all speeds.

Ford Prefect

3rd March 2013, 17:47

Ah, so he is! Darn! All that typing for nothing. :getmecoat:

Stewart; fitting an EAT ECU intended for another engine will almost certainly alter the gear change points on your V6 from their current optimum values. In my view such a move will just make things worse.

Simon

Indeed it probably will, I am really interested to see if the lockup speed can be reduced to one that means it won't need to be at motorway speeds when it does. The present situation will be leading to a needlessly high fuel consumption. I'm only interested in an alternative ECU to see what effect a lower lockup point will achieve and to see if its worth putting the work into altering the code in the 2.5 ECU. I'm not really looking at a permanent swap. The standard ECU seems to be the same on all V6 cars and the lockup point is excessively high for some reason which seems odd given the 825 would be locked up by 55, an that was only a 4 speed box and a larger car (although often steam powered!(

SD1too

3rd March 2013, 18:12

I am really interested to see if the lockup speed can be reduced to one that means it won't need to be at motorway speeds when it does.
Hi Stewart,

Remember that the ECU will probably have a complex algorithm for lock-up engagement. Road speed will certainly need to be constant and throttle angle small. MGR's statement that lock-up is available in gears 2, 3 & 4 as well confirms this. I still think that the fall in revs described has not been proven to be a result of lock-up. I think it is a change of gear which you are feeling.
The present situation will be leading to a needlessly high fuel consumption.
That is a purely academic argument. Lock-up is effected only in conditions when fuel consumption would be at its lowest value. By-passing the converter at a steady constant speed is not going to result in a huge decrease in revs. Even on the motorway, you will need to accelerate from time to time and that will require disengagement of lock-up. So all these factors should show that "needlessly high fuel consumption" is not on the cards.

What long distance fuel consumption are you getting, using the brim-to-brim method?

Simon

Ford Prefect

3rd March 2013, 19:56

Hi Stewart,

Remember that the ECU will probably have a complex algorithm for lock-up engagement. Road speed will certainly need to be constant and throttle angle small. MGR's statement that lock-up is available in gears 2, 3 & 4 as well confirms this. I still think that the fall in revs described has not been proven to be a result of lock-up. I think it is a change of gear which you are feeling.

That is a purely academic argument. Lock-up is effected only in conditions when fuel consumption would be at its lowest value. By-passing the converter at a steady constant speed is not going to result in a huge decrease in revs. Even on the motorway, you will need to accelerate from time to time and that will require disengagement of lock-up. So all these factors should show that "needlessly high fuel consumption" is not on the cards.

What long distance fuel consumption are you getting, using the brim-to-brim method?

Simon

A rather disapinting 31 - 33 MPG given that my 827 would do 36 and the 825 sterling 38 (both R17 KV6 and the XX C25a) the 75 should do better as its smaller and has a 5 speed box 33 is just not good enough!

I have to ask.. what on earth leads you to belive it has to unlock the TC to acclerate? manual cars manage to accelerate quiet well without having to slip the clutch. I assure you that the drop in revs at around 62-65 IS the TC locking up.. 5th is engaged at about 40 ish in normal driving. Similar statements about TC lock up in other gears were made for the Honda box from the 827, and were in fact false, rover also claimed the 220 turbo coupe had 'traction control'.. it didn't

It's a shame theres no instanatious reading on the trip computer, as there was on my XX sterlings and the XJ40s, the differance in locked up in 4th and unlocked was significant, the XJ40 I recall unlocked at 50 would read mis 20s instantaoius, and locked at an indicated 55 would read low mid 30s

SD1too

3rd March 2013, 22:53

A rather disapinting 31 - 33 MPG ...
I'd say that that's perfectly normal and quite good for a 2.5 litre V6. It doesn't indicate that there's anything wrong with your Rover 75.
I have to ask.. what on earth leads you to belive it has to unlock the TC to acclerate?
Because the driver's demand for acceleration might require the gearbox to change down (for example when ascending a gradient or to pass another vehicle in the shortest possible time), and it can't do that without the torque converter engaged. So at a particular throttle angle, lock-up has to be disengaged and the next lowest gear selected. You feel a drop in revs and think that it's just lock-up but it might be that plus a gear change.

My point is that it's impossible to be sure.

Simon

James.uk

4th March 2013, 01:02

kaiser said.....
>>>If un-locked, a light press/release on the speeder will result in a increase/decrease in engine revs at constant road speed, showing the slip in the torque convertor.
If locked: a light press/release on the speeder gives no change in the engine revs, thus showing the direct, locked linkage of the box.<<<

My Diesel auto gearbox works as described above. As the diesel uses more torque it is easier to tell the diff when applying just light throttle to gain speed.
It is possible with the diesel (in top gear) to keep gently adding power untill the auto box comes out of lockup and it can be clearly heard to increase revs without changing gear, add pressure faster and the car will change down a gear...
...

kaiser

4th March 2013, 03:20

I am going to try and explain this very slowly.:}

1. The torque converter is there to amplify torque, but that does include slippage. It is quite like a slipping clutch, except the torque converter is designed to do this, a clutch is not, except briefly on start-up.
It should therefore be clear, that the torque converter will help in any gear at lower revs, where the engine has almost no torque by itself.
Anyone who, for any reason, has started a manual car in high gear will now this, you can get the car to accelerate, albeit very slowly, but it will cost you a clutch!.
A lock up of your box in low gear and at low revs is therefore senseless and defies the total purpose of an automatic box.

2. Improved fuel consumption because the box is locked up will only happen if the car otherwise is driving in it's torque band. To lock up at 30 mph in top would be akin to trying to putter around at 30mph in top in a manual car. Most people would not do that, unless on slight down slope, but you would change down if required.

3. Simon, an un-lock and a gear change can be easily detected, if you look for it. If nothing else, start counting. It is really not that difficult. Go and try it or you will just continue confusing people.:cool:

And, finally admit, that the Rover manual is not the end all, be all. The lock up on the lower gears does not exist. It is maybe written, but it hasn't come to pass.

Ford Prefect

4th March 2013, 03:52

I'd say that that's perfectly normal and quite good for a 2.5 litre V6. It doesn't indicate that there's anything wrong with your Rover 75.

Because the driver's demand for acceleration might require the gearbox to change down (for example when ascending a gradient or to pass another vehicle in the shortest possible time), and it can't do that without the torque converter engaged. So at a particular throttle angle, lock-up has to be disengaged and the next lowest gear selected. You feel a drop in revs and think that it's just lock-up but it might be that plus a gear change.

My point is that it's impossible to be sure.

Simon

I don't think there is anything wrong with my car, I do think ther was somthing wrong with the way rover originally set the box up. It's almost as though they wanted it to use a lot of fuel! What is curious is it seems as though the 2.5 has the same gearbox ECU software as the 2.0, which is unexpecteded, it should bring a larger engine be capable of locking up sooner but does not, it's a though they only developed one v6 gearbox ECU, and that was tailored to the 2.0 and then hamstrung the 2.5 with the same ECU

As for unlocking of the TC to accelerate, that is entirely dependant on how much acceleration you ask for.

kaiser

4th March 2013, 04:21

There is no doubt that the gearbox has been set up mainly for comfort. Even in sport mode, there is an agonizingly long pause between each gear change.

The V6 engine is poor in terms of torque. It produces torque very high in the rev range and over a limited range, and very little at the lower range. This is a notorious difficult task to provide gearing for. The narrower the range, the more gears are required to stay withing that range, and the higher up the torque, the more you have a need for a torque converter.

As for accelerating in lock-up. Of course you can do that.
But it does not take much to nudge the box out of it, just showing how limited the torque of the engine actually is.

kaiser

4th March 2013, 04:50

http://forums.mg-rover.org/showthread.php?t=495606

for anyone who wants to know how poor the torque of the V6 actually is.
Don't read it if you are easily depressed!:getmecoat:

Ford Prefect

4th March 2013, 07:47

Takes a lot to depress me!, but looking at the figures.. WHY has the 2.5 been saddled with a gearbox ECU made for the 2.0?
from the data the torque for the 2.0 is

185 Nm peak at 4000

the 2.5 is

240 Nm [peak at 4000..

I can't find a torque plot for either of them, but as the 2.5 is a longer stroke engine I would expect to see a steeper initial curve (not miracles, just steeper than the 2.0) whihc would mean it would cause it no harm locking up sooner than the 2.0

MrDoodles

4th March 2013, 07:50

92 squadron

4th March 2013, 07:56

On the other side of the coin, mine appears to drop out of gear when decelerating at about 45mph. Is there a reason for this?

SD1too

4th March 2013, 08:35

It is possible with the diesel (in top gear) to keep gently adding power untill the auto box comes out of lockup and it can be clearly heard to increase revs without changing gear, add pressure faster and the car will change down a gear...
Thanks James, I'll continue to try to detect that on my car.

And, finally admit, that the Rover manual is not the end all, be all.
I have already done that in other threads, when I have firm evidence that the MG Rover manual is wrong, but you have clearly not seen those.

Just because there are errors in the manual does not make it safe to say that the manual "must be wrong" when something is not fully understood, or when there is little official guidance on the subject. That's how myths are spread.
The lock up on the lower gears does not exist
Kaiser; I suggest that you don't have evidence that that is definitely the case. You might be right or you might be wrong. Is it not possible that you might never have driven your car in the conditions required for lock-up in lower gears to be engaged? Yes, of course that's possible, because you don't know what those conditions are (and neither does anybody else except the manufacturers). MG Rover states that lock-up in the lower gears is "possible". That isn't the same as saying that the driver will normally experience it.

Simon

SD1too

4th March 2013, 08:43

it seems as though the 2.5 has the same gearbox ECU software as the 2.0, which is unexpecteded, it should bring a larger engine be capable of locking up sooner but does not, it's a though they only developed one v6 gearbox ECU, and that was tailored to the 2.0 and then hamstrung the 2.5 with the same ECU
We don't know that any of this is true, so it should not be taken as fact.

WHY has the 2.5 been saddled with a gearbox ECU made for the 2.0?
Who says that the ECU was made for the 2 litre?
The 2 litre transmission has some different gear ratios when compared with the 2.5.
Both engines' torque curves are influenced by the variable intake system. How do you know that those actuators aren't triggered at different points in the rev range, and/or at different throttle angles? ;)

Simon

kaiser

4th March 2013, 09:24

Thanks James, I'll continue to try to detect that on my car.

I have already done that in other threads, when I have firm evidence that the MG Rover manual is wrong, but you have clearly not seen those.

Kaiser; I suggest that you don't have evidence that that is definitely the case. You might be right or you might be wrong. Is it not possible that you might never have driven your car in the conditions required for lock-up in lower gears to be engaged? Yes, of course that's possible, because you don't know what those conditions are (and neither does anybody else except the manufacturers). MG Rover states that lock-up in the lower gears is "possible". That isn't the same as saying that the driver will normally experience it.

Simon

Simon. You claim the lock up is there. Now prove it! Simple as that.

I' m tired of proving things, so let's turn the can on it's head.

Just because there are errors in the manual does not make it safe to say that the manual "must be right" when something is not fully understood, or when there is little official guidance on the subject. That's how myths are spread.
So, please just prove ONE lock up in ANY gear apart from 5th under ANY condition, and I will yield. Even better, let us know of ANY person who has actually experienced it and can reproduce it. Just ONE person!
Failing that, admit for once that you are wrong. It is not that easy, I know! but on this, you are, if not wrong, certainly not right.

It becomes self defeating to harp the same story, unless you can prove it.

The ONLY possible explanation might be on over run, where the box acts as an engine brake. That I will admit I have never checked, but that is the only hope you have Simon.

Ford Prefect

4th March 2013, 09:28

We don't know that any of this is true, so it should not be taken as fact.

Who says that the ECU was made for the 2 litre?
The 2 litre transmission has some different gear ratios when compared with the 2.5.
Both engines' torque curves are influenced by the variable intake system. How do you know that those actuators aren't triggered at different points in the rev range, and/or at different throttle angles? ;)

Simon

Only 3 part numbers seem to be applied to 75 gearbox ECUS that I have found, that and the TC locking up at about teh same speed. One ECU part number I know to be that for the 1.8T, one of the remaining part numbers must be for the BMW engine, and we know they lock up much sooner, so that leaves just one for the V6 cars. The 2.0 auto ratios can't be that differnt, in top and final drive as the speed and RPM reported seem to be very similar to the 2.5.

Engine capacity has a FAR bigger influence than any electronic trickery messing with tract lengths!. And we can add the 2.5s oversquare dimensions to the equation which will also meant it will produce more torque will be biased to the lower part of the RPM range (physically the 2.0 is just a short stroke 2.5, another odd thing to do, had it been a 2.5 with a smaller bore then its torque may not have been so bad, although not as rev happy)

It would not take a huge change to make a big differnce in overall MPG, just lowering it to just under 60 as opposed to just over 60 would make noticable differnce (60 being the speed limit on most UK roads outside urban areas)

But back to the question.. 1.8T autos, what speed do they lock up at.. how do the ratios compare with the 2.5?

SD1too

4th March 2013, 10:17

The 2.0 auto ratios can't be that differnt, in top and final drive as the speed and RPM reported seem to be very similar to the 2.5.
Hi Stewart,

I'll give you MG Rover's figures and you can do the maths.

Fifth gear ratio is the same on all engines. Final drives are as follows:

Diesel 3.45:1
K1.8 & 2.0 V6 4.15:1
2.5 V6 3.89:1

From that data, I'd say that your ECU theory is a bit shakey. :} Isn't it more likely that the 1.8 and 2.0 V6 share the same ECU?

See how easy it is to jump to a conclusion before you know the full story? :D

Cheers,

Simon

Ford Prefect

4th March 2013, 11:15

Hi Stewart,

I'll give you MG Rover's figures and you can do the maths.

Fifth gear ratio is the same on all engines. Final drives are as follows:

Diesel 3.45:1
K1.8 & 2.0 V6 4.15:1
2.5 V6 3.89:1
From that data, I'd say that your ECU theory is a bit shakey. :} Isn't it more likely that the 1.8 and 2.0 V6 share the same ECU?

See how easy it is to jump to a conclusion before you know the full story? :D

Cheers,

Simon

Just the part numbers says the 1.8T does not share with the 2.0V6! it's way off sequence

But my original post was to find information, whihc has only recently been forthcomming

The 1.8T auto box has the same final drive as the 2.0 v6?? I suspect not I have a feeling those fuigures are the manual box due to the presence of the K1.8

It's also possible the ECU may not even look at speed, and be more interested in the RPM of the internal shafts. Be interetsing to see the pinout to see if there is a road speed input.

What I really don't get even if this is not the cause, is how rover manages to go from the 825 R17 sterling, returning 39 MPG extra Urban to the rather dismal 33 I have to work to get from the 75 when the 825 would get 37 without any real effort.. admittedly there is a weight gain, I think the R17 was 1460Kg and the 75 connie is 1505kg, however the 75 is also more aerodynamic at .29 compared to .32 for the R17 and we know the engine is an improved version of the 825 motor. The 5 speed auto box should also reduce the fuel consumption.

So a car with lower drag, more uptodate transmission with 5 speeds, weighing only 45kg more yet uses siginficatly more fuel? why, all I have noticed it the transmission resolutly refusing to lock up till it reaches an insanly high speed, the 825 locked up well before 60 which is the speed most of my driveing is done at

kaiser

4th March 2013, 11:28

My vehicle has just done 1418km. It used 139.2 liters. The average speed on highway was 110km/h (subtracting rest times) and of the total about 1180km on highway, the rest mixed. (110km/h is not as slow as it sounds)

that gives fuel consumption of 10.2km/l
or 28.8 mpg.

Tourer, 2.5V6, automatic, 3 people on board.

The only way to improve on this would be to reduce the speed, but even then, I don't think you would be able to get much more than about 30mpg.

kaiser

4th March 2013, 11:31

Just the part numbers says the 1.8T does not share with the 2.0V6! it's way off sequence

But my original post was to find information, whihc has only recently been forthcomming

The 1.8T auto box has the same final drive as the 2.0 v6?? I suspect not I have a feeling those fuigures are the manual box due to the presence of the K1.8

It's also possible the ECU may not even look at speed, and be more interested in the RPM of the internal shafts. Be interetsing to see the pinout to see if there is a road speed input.

What I really don't get even if this is not the cause, is how rover manages to go from the 825 R17 sterling, returning 39 MPG extra Urban to the rather dismal 33 I have to work to get from the 75 when the 825 would get 37 without any real effort.. admittedly there is a weight gain, I think the R17 was 1460Kg and the 75 connie is 1505kg, however the 75 is also more aerodynamic at .29 compared to .32 for the R17 and we know the engine is an improved version of the 825 motor. The 5 speed auto box should also reduce the fuel consumption.

So a car with lower drag, more uptodate transmission with 5 speeds, weighing only 45kg more yet uses siginficatly more fuel? why, all I have noticed it the transmission resolutly refusing to lock up till it reaches an insanly high speed, the 825 locked up well before 60 which is the speed most of my driveing is done at

Next thing to go is the damned cat!!
I have a strong suspicion that might well be the culprit.

SD1too

4th March 2013, 12:25

To answer your points Stewart:
The 1.8T auto box has the same final drive as the 2.0 v6?
MG Rover quotes the engine capacity; it does not give any separate data for the turbocharged 1.8. The 1.8 naturally aspirated has the same final drive as the 2.0 V6. Are you surprised?
... I have a feeling those fuigures are the manual box due to the presence of the K1.8
The figures are for the JATCo automatic transmission. Are you not aware that the 1.8 engine was available with that?
Be interetsing to see the pinout to see if there is a road speed input.
Yes there is. "Vehicle speed sensor" input on pin 5.

So how is your theory on different lock-up speeds looking now?

Simon

Ford Prefect

4th March 2013, 13:14

To answer your points Stewart:

MG Rover quotes the engine capacity; it does not give any separate data for the turbocharged 1.8. The 1.8 naturally aspirated has the same final drive as the 2.0 V6. Are you surprised?

The figures are for the JATCo automatic transmission. Are you not aware that the 1.8 engine was available with that?

Yes there is. "Vehicle speed sensor" input on pin 5.

So how is your theory on different lock-up speeds looking now?

Simon

Prvuits posst when I asked about the 1.8 gearbox ECU indcated there was no auto 1.8 so I assumed the only auto 1.8 was a turbo. And yes I'd be very surprised if the tubro had the same final drive as either the 2.0 V6 or 1.8 NASP, seems a shame to waste the best aspect of the turbo motor.. the vastly improved torque, lets face it the turbo does not exist to blow GTIs into the weeds, its there for much the same reason as it is on my XM, to provide efforltess cruising.

My theory is sound, the 2.5 locks up way too late and thats why it uses way more petrol than it needs to, I just want to find a way to get it to lock up at a sensible speed. The fact the 1.8T does so well on fuel says the 2.5 has no need to be so damn thirsty. Failing that its getting LPGd

bl52krz

4th March 2013, 14:49

Ford Prefect

4th March 2013, 14:54

Its not known as the HBOL for nothing!

kaiser

4th March 2013, 15:34

According to Haynes, the auto gearbox is able to lock up in 2,3,4,5 gears.?

We know that. They most likely have it from Rover, which then might have it from JATCO, or whatever.

But I have read that book myself, and I know it is wrong on many other issues.
We here have a claim of a three legged ostrich, and I say I have never seen one. I will believe you if you show me this animal. If not, go home and suck your thumbs.

It makes no sense, I have never seen it, and I have never heard of anyone who has seen it. I might be left, but I seriously doubt it.;)

But not to worry. Simon is doing that! But I bet it will be for naught.!

If you want me to believe in three legged ostriches, show me one!:D

SD1too

4th March 2013, 17:17

Failing that its getting LPGd
Stewart,

Would you really do that to a dealer launch car?

Simon

James.uk

4th March 2013, 18:26

Again, with the extra torque available on my diesel I have been unable to detect any auto box lockup other than in top (5th) gear.

As for engine braking, I just think the car has an inhibitor to stop it changing down, prob operated by the engine dragging rather than pulling. :shrug:
...

Ford Prefect

5th March 2013, 03:58

Stewart,

Would you really do that to a dealer launch car?

Simon

Why not? I do 30k a year, and it is for driving not polishing in a garage! (It's just turned 70k). However I'd not get too worried, I have an aversion to drilling big holed in bodywork and having found LPG does not add any value to a car (it really should, better than diesel running costs.. with the refeinement of a V6 rather than that of a tractor) so I want to be able to remove it in such a way no one would ever know it had been fitted. It's also far better for the engine than petrol

SD1too

5th March 2013, 17:39

... the Rover manual is not the end all, be all. The lock up on the lower gears does not exist. It is maybe written, but it hasn't come to pass.
Kaiser; I thought you'd be interested in what Citroen has to say about their AL4 automatic transmission. This is from their technical training document:

"Converter lock-up: Lock-up is available on 2nd, 3rd and 4th gears (and 1st gear in rare cases)."

Well fancy that. Does this mean that, in your view, Citroen is wrong as well? :eek:

Simon

kaiser

5th March 2013, 19:35

Kaiser; I thought you'd be interested in what Citroen has to say about their AL4 automatic transmission. This is from their technical training document:

"Converter lock-up: Lock-up is available on 2nd, 3rd and 4th gears (and 1st gear in rare cases)."

Well fancy that. Does this mean that, in your view, Citroen is wrong as well? :eek:

Simon

That sounds interesting, and this is most likely a JATCO box as well.
And let me then concede, there is most likely a lock up facility on the lower gears.;)

But, and this is what we are talking about, it is never used for normal driving.
If you understand what a torque converter does, namely more than doubling the engine torque, then it would also be obvious, that having a lock up working on the lower gears would make no sense whatsoever. On the contrary!
During acceleration through the gears, you want maximum torque to improve acceleration and locking up the converter would not give you any advantage!
So while this is said, there is absolutely no reason why you can't provide a lock-up in the lower gears as well, after all all, the hardware is there. It just makes no sense to do it for normal driving!
So when would it make sense.??
Maybe if you select 2nd gear and want to stay in that for towing purposes, to provide engine braking on a steep decline with a two ton trailer behind you. That I have never done, but it is feasible.
Maybe in an emergency, where the oil temperature is too high. ?
With the torque multiplication comes losses, and losses are translated into heat, and if the box gets too hot, it is entirely possible that there would be a reduced functionality to provide you with the means to get home, by locking the box and prevent the torque conversion, which generates heat. These are about the only situations where it could be done logically.

During normal driving, lock-up on the lower gears is dysfunctional/nonsensical/illogical and does not exist.;)

SD1too

5th March 2013, 21:59

... and this is most likely a JATCO box as well.
Not according to the Citroen Car Club of New South Wales who say this in their magazine:

"During the late 1990s PSA (Peugeot/Citroen), Renault and the German company Siemens, developed a new ... automatic gearbox called the AL4."

So, in fact, unlikely to be a JATCo box.

Simon

92 squadron

5th March 2013, 23:18

James.uk

5th March 2013, 23:37

Not sure how it fits in, but when the auto box on my prev white 75 played up, one of it's fav tricks was to lock me out of 4th and 5th gear. but although I drove many many miles in 3rd gear along mways (:o) there was never any sign of the box locking up in 3rd... :shrug:
...

kaiser

6th March 2013, 00:45

Not according to the Citroen Car Club of New South Wales who say this in their magazine:

"During the late 1990s PSA (Peugeot/Citroen), Renault and the German company Siemens, developed a new ... automatic gearbox called the AL4."

So, in fact, unlikely to be a JATCo box.

Simon

With the very close collaboration that has existed between Renault and Nissan over many years, there is very good reason to believe that JATCO is the maker of the box. Siemens would most likely provides the "brains" or the ECU.
JATCO is the supplier to (if not a direct subsidiary of) NISSAN and has been for many years.
And Renault/Peugeot are close to each other.

Both French makes are doing rather badly in the latest sales figures btw, and are more than decimated on the German market.

kaiser

6th March 2013, 01:04

http://www.kit-group.ru/sections/AL4%20Transmission.pdf

technical manual for the box

http://en.wikipedia.org/wiki/List_of_Jatco_transmissions

List of users of JATCO boxes.

SD1too

6th March 2013, 06:54

... there is very good reason to believe that JATCO is the maker of the box.
Not so long ago you told me to "stop believing":
Simon. Stop believing.
So Kaiser: stop believing!

Simon

Ford Prefect

6th March 2013, 13:19

With the very close collaboration that has existed between Renault and Nissan over many years, there is very good reason to believe that JATCO is the maker of the box. Siemens would most likely provides the "brains" or the ECU.
JATCO is the supplier to (if not a direct subsidiary of) NISSAN and has been for many years.
And Renault/Peugeot are close to each other.

Both French makes are doing rather badly in the latest sales figures btw, and are more than decimated on the German market.

This is the box used in the S2 24V XM.. and the 24v 3.0 espace, and a few others.. and its physically very similar to... the box found in the rover 825 odd that!

Ford Prefect

6th March 2013, 13:39

If memory serves me right on early Ford Cortina's and the like with three speed gearboxes you could lock the gearbox in 2nd by selecting the position 'L' and it stayed in that gear and would not be able to change up or down. As for locking in top gear this is a little baffling!:shrug:

Torque convertor lock up is a differnt thing!, the L would stop the gearbox form changing automatically, howerver the torque convertor would never lock up at all

The big problem with auto boxes has alsways been the torque convertor, if you imagine a fan blowing at a windmill you have a torque convertor.. only its not blowing air, its blowing gearbox fluid, the whole thing is encased to (to reduce losses and keep the fluid where you want it..). The fan is attched to the engine, the windmill to the gearbox. As you can imagine the fan turns faster than the windmill this introduces quiet significant losses, to get round this they fitted the two sides with a clutch, that can lock the two sides together (Locked up) this has 2 usefull effects, first being there are no losses, all the power is now transmitted to the gearbox, the second is the gearbox runs cooler when it's locked up as the energy that was being lost when not locked up is no longer being transfered to the fluid

James.uk

6th March 2013, 14:05

As above, but it's worth remembering that gearbox oil is non compressible. So with the vanes of the converter and the "windmill" only fractions apart, the driving force is pretty fierce innit!! :D:D
...

SD1too

6th March 2013, 14:46

This is the box used in the S2 24V XM.. and the 24v 3.0 espace, and a few others..
:confused: I'm not sure that this is correct either. There were two transmissions developed at the same time; the other being the 4HP20 for use in six cylinder engines (which your 24 valve units must be). That transmission is a ZF.
(Source: article by Citroen Car Club of NSW)

But in any case, you are taking Kaiser's argument that the AL4 may have been manufactured by JATCo as fact, which it is not. He has produced no firm evidence that JATCo had anything to do with it. If you have some, please post it.

Simon

92 squadron

7th March 2013, 00:10

Torque convertor lock up is a differnt thing!, the L would stop the gearbox form changing automatically, howerver the torque convertor would never lock up at all

The big problem with auto boxes has alsways been the torque convertor, if you imagine a fan blowing at a windmill you have a torque convertor.. only its not blowing air, its blowing gearbox fluid, the whole thing is encased to (to reduce losses and keep the fluid where you want it..). The fan is attched to the engine, the windmill to the gearbox. As you can imagine the fan turns faster than the windmill this introduces quiet significant losses, to get round this they fitted the two sides with a clutch, that can lock the two sides together (Locked up) this has 2 usefull effects, first being there are no losses, all the power is now transmitted to the gearbox, the second is the gearbox runs cooler when it's locked up as the energy that was being lost when not locked up is no longer being transfered to the fluid

Our engines still have a torque converter as such, but a modified form so the drive from the engine to the gearbox when it is locked up it is direct. Most gearboxes wether manual or automatic have a direct drive from engine to back axle and the differential gearing being reduction ratio .
On a BW [Borg Warner] box the the gear change was governed by a type of centrifuge, governed by road speed, load applied and throttle position, which in-turn applies the fluid to act on the pistons controlling the bands around the epicyclic gears but I think ours are controlled by the gearbox ECU:shrug:
:smilie_re:lookhere (http://www.allengears.com/html/epicyclic.php) to see how epicyclic gears work. And :smilie_re:Here (http://en.wikipedia.org/wiki/List_of_Jatco_transmissions) to see Jatco gear box applications.

Borg Warner

7th March 2013, 01:07

Our engines still have a torque converter as such, but a modified form so the drive from the engine to the gearbox when it is locked up it is direct. Most gearboxes wether manual or automatic have a direct drive from engine to back axle and the differential gearing being reduction ratio .
On a BW [Borg Warner] box the the gear change was governed by a type of centrifuge, governed by road speed, load applied and throttle position, which in-turn applies the fluid to act on the pistons controlling the bands around the epicyclic gears but I think ours are controlled by the gearbox ECU:shrug:
:smilie_re:lookhere (http://www.allengears.com/html/epicyclic.php) to see how epicyclic gears work. And :smilie_re:Here (http://en.wikipedia.org/wiki/List_of_Jatco_transmissions) to see Jatco gear box applications.

Did someone call?

Borg Warner

Ford Prefect

7th March 2013, 06:12

:confused: I'm not sure that this is correct either. There were two transmissions developed at the same time; the other being the 4HP20 for use in six cylinder engines (which your 24 valve units must be). That transmission is a ZF.
(Source: article by Citroen Car Club of NSW)

But in any case, you are taking Kaiser's argument that the AL4 may have been manufactured by JATCo as fact, which it is not. He has produced no firm evidence that JATCo had anything to do with it. If you have some, please post it.

Simon

That ZF was never used in any XM! The 4HP18 was, but the late 24v v6 XM and the v6 espace of the same time shared both the engines and gearboxes and I have seen both out of cars, they are identical. And the gear section of an 825 box is too similar to be unrelated. The bell housing is different however. I am not saying that it was made but JATCO, but there's certainly a large case for saying they had a common engineering team when designed. Manufacture is something else entirely.

Ford Prefect

8th March 2013, 10:03

By the way, if you don't belive the drop in revs that occours at 62-65 is the TC locking up try this and then try telling me its not the TC locking..

Get the car to an indicated speed between 55-60, put the cruise on. Now increment the speed 1 mph at a time, by tapping the cruise button and gradually increse the speed (1 mph at a time). You will notice the revs increse and then drop for each speed increment you do before you hit the drop in revs, however after that there is no rise adn fall, just an increase in speed, this can ONLY be because the TC is now locked. It will unlock as soon as you ask for any signifcant acelleration, or the cruise asks for any significant power to keep the speed steady up a steep hill or whatever.

You could also try the same test to see if it locks in any other gear.. my bet is it will not but it might lock in 4th if the selector is in '4' . I can't see it locking in any gear other that the highest you have selected to be avaialbe

SD1too

8th March 2013, 10:47

That sounds like a good test Stewart, thank you. I'll try it the next time that road conditions allow. :)

Simon

SD1too

29th March 2013, 08:33

kaiser

29th March 2013, 08:58

I guessed you must be on leave, because you didn't chirp in with your usual advice regarding filling the cooling system.:wink2:

Just to let you know, I have singlehandedly corrupted a member and suggested he just top up his expansion box when cold, not even mentioning lifting the expansion box, so I thought I better confess. I am sure he is now a lost soul forever, unless you rush over and pull him straight!!

Anyway, glad to see we now agree on the working of part of the gearbox.!
I never thought I would see the day!

Welcome back!

SD1too

30th March 2013, 07:50

Hello Stewart,

I have carried out a further test and I think you'll be interested in the result, and I hope reassured by it too! :)

Earlier in this thread you expressed disappointment in your 75's average fuel consumption:
A rather disapinting 31 - 33 MPG given that my 827 would do 36 and the 825 sterling 38 ...
You suggested that torque converter lock-up might be responsible, because it engaged at a speed which you felt was too high. I hope that this is a fair summary.

Yesterday, after two very long journeys almost entirely at constant cruising speeds, I filled my tank with 52 litres of unleaded. My brim-to-brim calculation gave an average of 32.2 mpg and the trip computer (reset at the last fill-up) showed 32.1. So, with this type of driving I concluded that the readout can be trusted.

I then joined a quiet motorway and covered 25 miles at a steady, indicated 70 mph. The engine was already warm so no cold starts were involved. I detected the lock-up engaging and disengaging from time to time, depending upon the road's gradient. Based on my refilling evidence above, I knew that upon leaving the motorway the trip computer would give a reliable indication of a 2.5 automatic's fuel consumption at steady motorway speeds, albeit in ideal traffic conditions. It read an astonishing 38.1 mpg. :eek:

I stress that this is not an average figure since it does not take into account cold starts, idling, and repeatedly accelerating a laden vehicle from rest. However, it does show that the JATCo transmission is capable of being as economical with fuel as a manual gearbox on long distance cruising.

Once I had travelled a further 7 miles at 30 and 40 mph with several sets of traffic lights, the computer's readout had dropped to 36 mpg average. I am in no doubt that the next time I use the car it will be heading towards its more usual 30 to 31 average (when long distances are included).

So, my 25 mile test included no cold start, no braking, a mild rate of acceleration and virtually a steady speed throughout. With the torque converter active at some times and lock-up engaged at others, the fuel consumption was fantastic; so I think this exercise shows that it is, in fact, realistic modern driving conditions which are responsible for poor fuel consumption from automatics. The evidence doesn't really support the idea that the lock-up system is a significant factor.

Simon

Ford Prefect

2nd April 2013, 08:27

Hello Stewart,

I have carried out a further test and I think you'll be interested in the result, and I hope reassured by it too! :)

Earlier in this thread you expressed disappointment in your 75's average fuel consumption:

You suggested that torque converter lock-up might be responsible, because it engaged at a speed which you felt was too high. I hope that this is a fair summary.

Yesterday, after two very long journeys almost entirely at constant cruising speeds, I filled my tank with 52 litres of unleaded. My brim-to-brim calculation gave an average of 32.2 mpg and the trip computer (reset at the last fill-up) showed 32.1. So, with this type of driving I concluded that the readout can be trusted.

I then joined a quiet motorway and covered 25 miles at a steady, indicated 70 mph. The engine was already warm so no cold starts were involved. I detected the lock-up engaging and disengaging from time to time, depending upon the road's gradient. Based on my refilling evidence above, I knew that upon leaving the motorway the trip computer would give a reliable indication of a 2.5 automatic's fuel consumption at steady motorway speeds, albeit in ideal traffic conditions. It read an astonishing 38.1 mpg. :eek:

I stress that this is not an average figure since it does not take into account cold starts, idling, and repeatedly accelerating a laden vehicle from rest. However, it does show that the JATCo transmission is capable of being as economical with fuel as a manual gearbox on long distance cruising.

Once I had travelled a further 7 miles at 30 and 40 mph with several sets of traffic lights, the computer's readout had dropped to 36 mpg average. I am in no doubt that the next time I use the car it will be heading towards its more usual 30 to 31 average (when long distances are included).

So, my 25 mile test included no cold start, no braking, a mild rate of acceleration and virtually a steady speed throughout. With the torque converter active at some times and lock-up engaged at others, the fuel consumption was fantastic; so I think this exercise shows that it is, in fact, realistic modern driving conditions which are responsible for poor fuel consumption from automatics. The evidence doesn't really support the idea that the lock-up system is a significant factor.

Simon

Actualy you have just proved the late lockup IS partly responsible! you have very similar figures to my own car. At motorway speeds it is locked up, and indeed does rather well. However below 62 the MPG plummets.

Try this test, assuming you have a road suatable you travel reguarly. Get it to the lockup speed, set the cruise, rest the avg MPG on the trip, travel a known distance. Make a note of the reading. Then try the same just below the lockup on the same road in the same direction. Then tell me the lockup makes no differance!

Ford Prefect

3rd April 2013, 08:01

Well, I have just returned from a long trip including much motorway cruising in good traffic conditions. It wasn't sufficiently quiet to carry out Stewart's test to the letter, but on accelerating gently to the legal limit I did detect a drop in engine speed of about 300 rpm. I must congratulate those who identified this because it's so smooth and occurs barely one second after the engagement of fifth gear. It's therefore easy to miss if you're having to concentrate on traffic movements at the time. It did indeed occur at approximately 60 mph.

Simon

Err.. mine changes to 5th at around 44 ish, the changeup point seems to be around 2000-2100 rpm, 1-2nd occurs at about 10mph, 2-3rd at shade over 20, 3rd - 4th at 33 ish, and the final one at 44ish we do have much the same cars so this is odd

SD1too

3rd April 2013, 08:57

Err.. mine changes to 5th at around 44 ish, the changeup point seems to be around 2000-2100 rpm, 1-2nd occurs at about 10mph, 2-3rd at shade over 20, 3rd - 4th at 33 ish, and the final one at 44ish we do have much the same cars so this is odd
Hi Stewart,

Those are very low engine speeds. Are you driving with an extremely light right foot?

Simon

Ford Prefect

3rd April 2013, 10:42

Hi Stewart,

Those are very low engine speeds. Are you driving with an extremely light right foot?

Simon

Not that anyone who has been in the passenger seat has noticed! but its possible, I can usually beat manufacturers claimed MPG if I try, however in this case I am not, I find you do have to be 'making progress' to get it to hang onto gears much longer than that. It's not much differnt in that respect to most of the other autos I have had. I do rather like the noise at 3K+.. However there are a number of downsides to that.. fuel guage moves way too fast, not to mention the posiblity of the blue lights and wailing noises that can occur.. not a great fan of either issue!

Steve1966

3rd April 2013, 12:03

On the other side of the coin, mine appears to drop out of gear when decelerating at about 45mph. Is there a reason for this?

I haven't read every single post on this thread so forgive any duplication etc. I recall during 75 development that we were suffering excessive brake pad wear on the autos during city centre driving and the ecu was reprogrammed to ensure that it changed down the box more readily to invoke some (albeit small) engine braking to reduce the brake pad wear. On a particular Birmingham city centre route the front pads would only last 6000 miles prior to this change.

Steve.

SD1too

3rd April 2013, 13:20

... I find you do have to be 'making progress' to get it to hang onto gears much longer than that.
Stewart; have you checked your VIS actuators recently, and the balance valve for stickiness? I also recently cleared out the crankcase breather pinholes in the cam covers and that has had a beneficial effect upon the engine's response and gear changing.

Simon

Ford Prefect

3rd April 2013, 14:10

Stewart; have you checked your VIS actuators recently, and the balance valve for stickiness? I also recently cleared out the crankcase breather pinholes in the cam covers and that has had a beneficial effect upon the engine's response and gear changing.

Simon

RE vis actuators, first job I did, took them off, put the 2 scews through the switches and resoldered them, then fitted sealed ball bearings to the ouptut shafts.. I am looking for a broken inlet though, as I want one to experement with, as I think the butterfly valve actuation joints are utter *****! and am pretty sure I can do better, I do have an 825 inlet as well, and it would be inetresting to know if the tract length is much the same, if it is then the differnt RPM the 825 opperates it at are irrelevant although the TC would have to go if I fitted that as the twin TB has no provision for the TC throttle

SD1too

3rd April 2013, 19:08

... I think the butterfly valve actuation joints are utter sh1te!
If you're talking about the power valves remember that they only open at very high engine speeds; way above the torque converter lock-up point in 5th. If those valves open, lock-up would be disengaged and the gearbox would have changed down dramatically with an unholy growl from the V6 which will even result in an exclamation from SWMBO in the passenger seat. :D

I strongly recommend that you check the balance valve flap. If yours is sticking (and most do) it will make the performance very flat and lifeless.
Clear the camcover pinholes as well. These are the things which will have the greatest impact upon everyday driving, and the fuel consumption of which you complain.

Cheers,

Simon

Ford Prefect

4th April 2013, 08:47

kaiser

4th April 2013, 15:03

I don't think it has many issues, as I say its getting a regular 30 - 33 mpg tank to tank, which seems normal for a healthy 2.5 however I think it can do better, a lot better, but I will have a look, always worth checking things out, not much to loose!

Why do I think it can do better? the 825 is why. Very similar weight, but inferior aerodynamics, and on paper inferior gearbox, however somehow uses notcably less fuel with the same engine (I know it was extensivly modifed to address the head issues but its still very similar) Even rovers figures say it uses less fuel.. Why? it shouldn't so fact teh TC's bhavoiur is the only signicant differance that could have that large a bearing on it. At M-way speeds it does indeed use less fuel than the 825, but on A-B roads the situation is reversed, where speeds are on the whole below the TC lockup speed for the 75, but not for the 825.

I don't expect in town driving to be anything other than dismal in terms of MPG, but cruise at 60 should use less fuel than cruise at 70, it doesn't! in fact at 50 it's still using more than at 70

I am thinking about a manual lockup switch, just to test what happens, but I do want some form of interlocking to overide it should the box want to change gear (I'm interestind enough to try, not instrested enough to break somthing!)

I think the lock up is largely a red herring for fuel economy. The reason I say that, is the fact that the manual car is not particularly frugal either.
A 10% loss is more or less the penalty for an autobox.
But if you look at what has transpired in between the 825 and the 75, I would guess that the emission control has vastly been beefed up.
In contrast to what many people might think, fighting pollution, can actually make the car thirstier. For a number of reasons, relating to the catalyst, and the mixture settings. I think the removal of the cat will give extra power and a re-calibration of the mixture ratio would provide an added bonus to that.

Union Wheels

4th April 2013, 15:55

"It's a shame theres no instanatious reading on the trip computer, as there was on my XX sterlings and the XJ40s, the differance in locked up in 4th and unlocked was significant, the XJ40 I recall unlocked at 50 would read mis 20s instantaoius, and locked at an indicated 55 would read low mid 30s"

Hi Ford Prefect,

there is an instant mpg read out in the onboard diagnostics all Rover 75 have. This is operated by the trip mileage button, (No.19 then No.4). It shows litres per 100 kilometers, but from it you will be able to tell how much difference there is between locked and unlocked TC before you go to a lot of trouble/cost trying to change when the lock up occurs.

Cheers Pete.

wutang

4th April 2013, 16:28

After doing alot of long runs in the last few weeks I can say my torque converter locks up in fifth at 58 MPH and will stay locked under reasonable acceleration.

with regards to better MPG I have made a significant improvement in my car by switching from 215/55/r16 wheels to 195/65/r15 wheels and I do mean significant.

Richard

Ford Prefect

4th April 2013, 21:44

Ive often wondered about wheels, as the drag racers always go for small wheels/tall tyres and I figured that the shift of weight away from the centre of roation by using a larger wheel was the reason the smaller wheel (but taller tyre so the same rolling radius) was the reason, and thus smaller wheels would also result in better MPG figures

carlpenn

5th April 2013, 00:19

Just read this and someone needs to explain this "Lock up" thing in Baby talk lol.

I have no idea whats going on!!! Being new to Auto - I am now curious lol :D:D:D:D:D:D

wutang

5th April 2013, 08:35

Just read this and someone needs to explain this "Lock up" thing in Baby talk lol.

I have no idea whats going on!!! Being new to Auto - I am now curious lol :D:D:D:D:D:D

In a traditional auto the torque converter provides the mechanism that transfers power from the engine through to the gearbox, it is basicaly a hydralic unit (i think of it as a turbine) as such it allows a certain amout of 'slip' so when you accelerate the engine will rev higher than the gear ratio would allow this helps to amplify the torque. the downside is this is why autos suffer worse MPG.

Lock up is a feature that on our cars 'Locks' the engine input to the gearbox input and so cuts down the torque converter losses making the system more effiecent, a bit like being in top in a manual box.

Don't know if I have been any help.

Richard

egremont

5th April 2013, 08:40

Hope this doesn't duplicate any comments, but from my notes, lock-up is possible in 2nd, 3rd, 4th and 5th gears.

Could our cars (KV6) fuel economy be improved by remapping the EEPROM?

Lock-up control:
The EAT ECU monitors the relationship between vehicle speed and throttle position to decide when to lock=up the torque converter. Lock-up control is possible in forward gears 2, 3, 4 and 5. For example, lock-up is possible at high vehicle speed with low throttle position, cruising.

A refinement to the torque converter lock-up position is the reduction of harshness or shock during lock and unlock. The EAT ECU actuates the lock-up solenoid , which gradually varies the fluid pressure in the lock-up control valve. This causes the lock-up clutch to engage and disengage slowly, thus producing a smooth operation.

To promote engine warm-up at low temperature, the EAT ECU will inhibit lock-up if the gearbox fluid temperature is below 40°C (104°F).

Electronic Automatic Transmission (EAT) ECU.

The EAT ECU uses a “flash” Electronic Erasable Programmable Read Only Memory (EEPROM). This enables a new or replaceable EAT ECU to be externally configured. EEPROM also allows the EAT ECU to be updated with new information and market specific data. To input new information and market specific data the EAT ECU must be configured using Testbook. It can be reconfigured as many times as you want.

carlpenn

5th April 2013, 09:08

In a traditional auto the torque converter provides the mechanism that transfers power from the engine through to the gearbox, it is basicaly a hydralic unit (i think of it as a turbine) as such it allows a certain amout of 'slip' so when you accelerate the engine will rev higher than the gear ratio would allow this helps to amplify the torque. the downside is this is why autos suffer worse MPG.

Lock up is a feature that on our cars 'Locks' the engine input to the gearbox input and so cuts down the torque converter losses making the system more effiecent, a bit like being in top in a manual box.

Don't know if I have been any help.

Richard

I get it now, sort of :D

Thank You :D

Ford Prefect

5th April 2013, 10:46

Ford Prefect

5th April 2013, 12:34

I think the lock up is largely a red herring for fuel economy. The reason I say that, is the fact that the manual car is not particularly frugal either.
A 10% loss is more or less the penalty for an autobox.
But if you look at what has transpired in between the 825 and the 75, I would guess that the emission control has vastly been beefed up.
In contrast to what many people might think, fighting pollution, can actually make the car thirstier. For a number of reasons, relating to the catalyst, and the mixture settings. I think the removal of the cat will give extra power and a re-calibration of the mixture ratio would provide an added bonus to that.

I think you underestimate the losses in the TC when unlocked. As I said earlier on cars that had an instantanious MPG readout on the trip computers a very noticable differnace can be seen when from just below lockup to just over it. At a constant engine speed the management would be running closed loop, which will be stoic so any emision mandated alterations between the 75 and the 825 become irrelevant. Although with the TC unlocked the engine will be running open loop most of the time whihc will bring any such changes into play, but this situation would occour far less often if the TC would lock up earlier

kaiser

5th April 2013, 13:03

I think you underestimate the losses in the TC when unlocked. As I said earlier on cars that had an instantanious MPG readout on the trip computers a very noticable differnace can be seen when from just below lockup to just over it. At a constant engine speed the management would be running closed loop, which will be stoic so any emision mandated alterations between the 75 and the 825 become irrelevant. Although with the TC unlocked the engine will be running open loop most of the time whihc will bring any such changes into play, but this situation would occour far less often if the TC would lock up earlier

I have noticed the lock up on the 1.8T is much lower.
However the torque of the V6 is simply not there at anything below about 2000 revs.
It is like pushing on a string, nothing really happens. Locking up here is simply not very smart.

SD1too

5th April 2013, 13:08

However the torque of the V6 is simply not there at anything below about 2000 revs.
It is like pushing on a string, nothing really happens.
Not true. I think you need to check your VIS actuators and clear the crankcase breather pinholes in your cam covers Kaiser. :D

Simon

kaiser

5th April 2013, 13:24

http://www.the75andztclub.co.uk/forum/showthread.php?p=1149144

wutang

5th April 2013, 13:47

Not true. I think you need to check your VIS actuators and clear the crankcase breather pinholes in your cam covers Kaiser. :D

Simon

Kaiser is I pressume still running with a butterflyless manifold so power vis doing nothing but sealing the hole!

From my experiance of testing a striped out manifold I did get more at the top end but deffinatley lost low down torque up to about 2600 rpm.

Richard

Union Wheels

5th April 2013, 13:51

I think you underestimate the losses in the TC when unlocked. As I said earlier on cars that had an instantanious MPG readout on the trip computers a very noticable differnace can be seen when from just below lockup to just over it. At a constant engine speed the management would be running closed loop, which will be stoic so any emision mandated alterations between the 75 and the 825 become irrelevant. Although with the TC unlocked the engine will be running open loop most of the time whihc will bring any such changes into play, but this situation would occour far less often if the TC would lock up earlier

Hi Ford Prefect

All Rover 75 cars do have have an instantanious MPG readout in litres/100km form. See post 96

Cheers, Pete.

SD1too

5th April 2013, 14:03

Kaiser is I pressume still running with a butterflyless manifold ...
Thanks Richard. :D That would probably explain it, although Kaiser has always said that removing the power valves had no detrimental effect. No doubt he considers that his lack of torque is due to another factor entirely. ;)

Simon

Ford Prefect

5th April 2013, 14:08

Hi Ford Prefect

All Rover 75 cars do have have an instantanious MPG readout in litres/100km form. See post 96

Cheers, Pete.

I had read that, hoever the button on my trip is not currently functional!

Ford Prefect

12th April 2013, 13:02

My own experements this last week,

same road, same direction at the same time, no traffic. Trip computer reset at the same point, MPG reading taken passing the same road sign using crusie to maintain constant speed

70 mph in 5th locked up, 42MPG
50 mph in 5th unlocked, 37MPG

I do think the lockup makes more of a differance that is belived! (I don't think the MPG reading are accurate, but teh % differnace is. Bear in mind it should be using more fuel at 70 not less! and thats a 12% loss as it is. I think thats worth reclaiming however a quick calcualtion says that at 50 locked up the engine would be turning at just under 1600 RPM which might be excessivly low. I may try this though as long as the RPM drop it not likely to make the box change down!

SD1too

12th April 2013, 13:08

70 mph in 5th locked up, 42MPG
50 mph in 5th unlocked, 37MPG
Stewart; you should know that only one factor should be changed in any one experiment. So your car needs to be travelling at the same constant speed in both tests.

Simon

Ford Prefect

12th April 2013, 14:44

Stewart; you should know that only one factor should be changed in any one experiment. So your car needs to be travelling at the same constant speed in both tests.

Simon
I have only changed one factor, Speed. If we ignore the lockup as it has been sugessed it is a red herring, at 50 the car should be using less fuel than at 70. What this prooves is that the lockup IS a significant factorl. It also sugessts that as at a lower speed its using 12% more fuel, then at 70 locked up then the % differnce would be even worse. With some sums I could tell you what it would be at 70 unlocked, but as the TC locks up before it reaches 70 then its rather difficult to get actuall figures. What this does prove is that there are savings of about 10% to be had by having it locked at A-B road cruiseing speeds

kaiser

12th April 2013, 15:10

I am afraid I don't like your testing at all.
Simon is right, something should be constant, and I will tell you why.

Your resistance to movement increases with speed. I don't think it will be very significantly higher at 70 than at 50, but I don't know. One would have to calculate.

You are right, normally you would expect the fuel economy to improve, the slower you go, but that does not always apply.

Any engine will have a particular spot, where the fuel economy is maximized. It will usually be close to the point where you have maximum torque.

At low speed the engine could become quite un-economical for many reasons, not least the throttling losses through the inlet butterfly.

I also don't like using the computer, but that is beside the point, as I will grant you that comparison should be giving a good pointer if not absolute figures.

So, what to do?
I would do the following two tests.
In both cases over a ten mile stretch as level as possible measure each test both directions, give a mile or so to get up to speed so you go in and out of the test with a constant speed.
1. Same engine revs throughout, with lock up, without lock up.
2. Same speed, with lock up, without lock-up.

1. will give you the same (or nearly the same) engine conditions except for slightly less throttle loss in the higher gearing.
2. will give you the same load on the engine from external resistance

that would be the best comparison I can come up with.

SD1too

12th April 2013, 15:18

I have only changed one factor, Speed.
Two factors changed Stewart: road speed and the function of the torque converter.

Simon

James.uk

12th April 2013, 16:43

>>>So your car needs to be travelling at the same constant speed in both tests.<<

Can't be done, coz you have no way of turning off the auto lock-up innit. :shrug:

My diesel does lock up in most gears, but it's undetectable, the only way I know is sometimes the car is slower to pick up speed under gentle acceleration, you can hear the engine noise change slightly, and speed does increase, but it seems to be done by torque increases rather than added revs.... :shrug:

I assume the V6 will be the same, but it will be far more sensative due to having less available torque at low revs..

If. you reprogrammed the eprom to produce lock-up at say 50 mph, you would only have to breathe hard to disengage it again.. No torque available to accelerate innit. :o :shrug:
...

SD1too

12th April 2013, 17:54

>>>So your car needs to be travelling at the same constant speed in both tests.<<
Can't be done, coz you have no way of turning off the auto lock-up innit.
I quite agree. But that's what would be necessary to prove Stewart's hypothesis.

If you reprogrammed the eprom to produce lock-up at say 50 mph, you would only have to breathe hard to disengage it again.. No torque available to accelerate innit.
I agree again. The lock-up speed was no doubt chosen to suit the engine characteristics. So if Stewart changes this, the engine will have to work harder in lock-up to achieve his desired road speed and, in the process, use more fuel. So he will not achieve what he hoped to.

Simon

Ford Prefect

15th April 2013, 10:03

Two factors changed Stewart: road speed and the function of the torque converter.

Simon

You are correct and I am not denying this.

However if was true that the TC lockup makes no siginifant differance then the function of the TC could be discounted. And so only speed has changed. The results prove that this is not the case and thats all the test was required to prove (or 50 would produce better MPG than 70 locked or unlocked)

I could repeat at a number of other speeds below lockup and extrapolate the MPG at 70 unlocked and then do the same for speeds above TC lockup, to gove an idea of what sort of improvemnt could be found, but I do not have the time for a meaningfull result.

What it proves is that there is a gain to be had, nothing more, no numbers

I'd not set the lockup for 50, more likely 55, that will do me just fine as most of my motoring is done on A-roads. Pretty sure the engine will cope just fine at this speed, having driven a manual and an 825 auto.

Ford Prefect

15th April 2013, 10:41

So if Stewart changes this, the engine will have to work harder in lock-up to achieve his desired road speed and, in the process, use more fuel. So he will not achieve what he hoped to.

Simon

Yes and unlikely. Yes the engine will have to work harder, unlikely overall it will use more fuel than unlocked as a greater % of the power is being used usefully

We could have a look at a manual 2.5 75 at 50 in top, if the gearing is the same, but the only comparison I have is a ZT190.. and the gearing on that is definatly not the same.. as it's doing 3000rpm at 70 and my 75 is 2200 ish at 70.

But rovers own extra urban figures for the 2.5 manual and Auto say there is a worthwhile gain, 32mpg for the auto (about what I get) and 39mpg for the manual. Most of my driving is 'Extra Urban' as I am in fairly rural england, so the combined/urban are not relevant to me

Ford Prefect

19th April 2013, 09:54

Right.. I have found the source of the lockup signal, all I need to know now is if its 5v or 12v. I shall place a diode in to prevent backfeeding the ECU and when I know the correct voltage to apply arrange a switch so I can lock/unlock at will. As mentioned I won't be trying this at 50 mostly as I have a feeling the gearbox might try and change down when the RPM drops with the TC locked. I'll probbly try it at an indciated 60 as thats what most of my driving is done at.

From looking about the overall gearing in 5th is very differnt between the auto and manual 2.5 V6, at 70 the wheels on a manual V6 are turning at 826 RPM and on the Auto 689. Why the auto is so high geared I have no idea, its relativly normal for the auto version of most cars to be slightly higher geared but not to that extent!

Out of interest, is the speedo opperated from the ABS? just thinking of a simple PIC to enable/disable the lockup below a fixed speed should it drop below a certain speed so its unlocked before any down shift occours, it could also monitor the other gearbox soloniods for the same reason.. (unless soemone with a T4 knows how to change the lockup parameters)

kaiser

19th April 2013, 13:55

Ford Prefect

19th April 2013, 14:16

Why not go the full length?

Now you have found the wire for the lock-up, it would also be nice to find the wires for the gears. In sport mode I would actually like to be able to shift the gears "manually". So maybe a little joystick that would enable us to manually select gears?

The delay in between the gear changes, even in sport, is highly annoying. It is OK for comfort, but when you select "S" you want it to shift both the one and the other way!
;)
I would be in the market if it could be done.!

Thats slightly more difficult, as its a combination of valves for each gear (and thus a combination of soloniods) but VW have done just that (ish) with their version of what looks to be essentially the same box (JATCO sourced and very identical to look at) but thats in the 'tiptronic' style manual selection. Might be intersting to see the VW ECU pinout to comapre to the 75 one

kaiser

19th April 2013, 15:00

Well, it can be done. The question is just, by whom!?

But now the be has been put in the bonnet let's see where it comes out!:}

DerekS

19th April 2013, 17:09

It HAS been done . Had it on both my 75 diesels ....by using a big stick mounted in the floor... called a MANUAL BOX . :D

James.uk

19th April 2013, 17:26

>>>at 70 the wheels on a manual V6 are turning at 826 RPM and on the Auto 689. Why the auto is so high geared I have no idea,<<<

Based on the above, the auto should be about 12% more economic than the manual???? But in reality, the reverse is the case innit??? :shrug:

Changing gear manually by moving the auto gear lever yourself is fine, but you would need to oil-grease up all the linkage as it is pretty stiff normally. :o

The best way to take a few fast corners is to lock the box in 3rd as you enter the bends, but it's a heavy car and you will get some scary moments when it shifts it's weight.. :o
...

LeRich

19th April 2013, 19:16

From looking about the overall gearing in 5th is very differnt between the auto and manual 2.5 V6, at 70 the wheels on a manual V6 are turning at 826 RPM and on the Auto 689.

Your calculations are a bit off here - assuming a V6 manual and a V6 auto have the same diameter wheels they will rotate at the exact same speed at 70mph.

Why the auto is so high geared I have no idea, its relativly normal for the auto version of most cars to be slightly higher geared but not to that extent!

The diesel auto is the same - the gearing is a lot higher than the manual.

Ford Prefect

22nd April 2013, 07:21

Your calculations are a bit off here - assuming a V6 manual and a V6 auto have the same diameter wheels they will rotate at the exact same speed at 70mph.

The diesel auto is the same - the gearing is a lot higher than the manual.

Temporary brain fade..

kaiser

25th April 2013, 15:23

Well, quoting from "Rover owner's guide to the Borg Warner Fully Automatic Transmission as fitted to the Rover 3 Litre"

Direct Drive is "Top Gear" in Drive. In Direct Drive, engine output is transmitted directly to the road wheels by a friction type clutch. This is a unique feature of the Borg Warner Automatic Transmission.

and:
Fuel Economy. The outstanding feature of this transmission is the by-passing of the torque converter and gearbox in Direct Drive which is used most of the time for normal motoring. Consequently, for equivalent performance, the Borg Warner Automatic Transmission does not increase fuel consumption.

I didn't know that. Now i do, and feel much better!!

wutang

25th April 2013, 16:59

Why not go the full length?

Now you have found the wire for the lock-up, it would also be nice to find the wires for the gears. In sport mode I would actually like to be able to shift the gears "manually". So maybe a little joystick that would enable us to manually select gears?

The delay in between the gear changes, even in sport, is highly annoying. It is OK for comfort, but when you select "S" you want it to shift both the one and the other way!
;)
I would be in the market if it could be done.!

Hi kiaser,

This should not actualy be as hard as you might think as in the rover 45 2.0v6 it is the same jatco box which comes with...........tiptronic function in that the stick is moved sidways to select sport and can be pushed forward and pulled back to go up and down gears, so the facility is there.

I looked into this tentetivley a while back, ie getting hold of the shifter from a 45 and seeing what sort of conection differences there are.

http://www.scribd.com/fullscreen/36560290?access_key=key-snglupafk4ikkvvqjb8

Hope link works go to page 82

Richard

wutang

26th April 2013, 08:46

Also the freelander 2.5 has the steptronic function which is same engine and gear box, a freelander auto gear shift can be had for £20 off ebay so I might get one to examine to see the differences.

kaiser

26th April 2013, 15:25

Also the freelander 2.5 has the steptronic function which is same engine and gear box, a freelander auto gear shift can be had for £20 off ebay so I might get one to examine to see the differences.

That all sounds interesting.
If I could select Sport and the have a small toggle switch to move up or down a gear without getting the engine to reduce torque etc, I think it would be a distinct improvement.
I would be very interested in what that would require.
What does the Freelander shifter do, and how does it look?

Borg Warner

26th April 2013, 18:06

That all sounds interesting.
If I could select Sport and the have a small toggle switch to move up or down a gear without getting the engine to reduce torque etc, I think it would be a distinct improvement.
I would be very interested in what that would require.
What does the Freelander shifter do, and how does it look?

Here's a hippo auto gear change. You can see the symbols S/M - Sport Manual. You simply move the stick to the right and it initially goes to Sport Mode, however moving forwards/backwards initiates the manual change for the driver. Very handy if you want to use the box to slow down. T/C lock up on it engages at around 45mph, not sure if it comes in any earlier though. Haven't tried it in any of the lower gears and although you don't feel it there is a noticeable visual drop of around 200 rev's when you go back into 5th and restore the box to auto.

I think there's some form of separate control for the auto box to cater for the Tiptronic availability.

Oh and you are of course correct regarding the Borg Warner 3 speeds Type 35!!!

Hope this helps.

Borg Warner:)

Ford Prefect

29th April 2013, 08:32

Borg Warner

30th April 2013, 14:02

It would not actually surprise me if all you needed was the selector and that the ECU is in fact the same, we just don't have the switches for the steptronic.

Instering about the TC lockup, what is the final drive ratio on a freelander?

Sorry don't have the details to the final drive ratios. 2000revs = 50mph indicated, but the speedo is very optimistic, according to satnav this is about 47 (70 on speedo shows 65 on satnav). It switches into 5th at just under 50 when the revs drop to around 2200; then very shortly after it drops again to 2000. This seems much earlier then your 75? Still only gives me 20/gal around town and 25ish on a run though. The consequence of driving around in a 4x4 shaped like a brick I suppose.

Sorry to hear of your mishap with your car. Hope you get it going again soon, would be a shame to lose it.

PS it's not Tiptronic is Command Shift; should have realised.

Gary M.