Sport mode & cruise control

[Dorchester2]

Hello all petrolheads!

Owner's handbook p. 120 (1999) & p. 112 (2003):
Use of 'sport' mode on automatic gearbox vehicles is not recommended when cruise control is selected.

Why? For what technical reason? What might be the issue?

I've used both at the same time on several occasions in the past without the slightest drawback!
So what?

Thanks.

[clf]

Originally Posted by Dorchester2

Hello all petrolheads!

Owner's handbook p. 120 (1999) & p. 112 (2003):
Use of 'sport' mode on automatic gearbox vehicles is not recommended when cruise control is selected.

Why? For what technical reason? What might be the issue?

I've used both at the same time on several occasions in the past without the slightest drawback!
So what?

Thanks.

I may be wrong, but on the technical side, it could it perhaps be due to additional fuel usage (cruise can help improve fuel.economy, plus lock up would not be engaged).

Also a practical issue I could see being an issue (to me at least) would be the extended acceleration could be unsettling. After disengagement of the cc, then the resume function applied.

Sent from my SM-A600FN using Tapatalk

[rovertone]

I find that when in Sport mode (which I rarely use) the box doesn't seem to want to shift into 5th gear, I've always assumed staying in 4th to provide the sharper response which is not what cruise control would be seeking to do, in other words working against each other.
Having said that I do find it strange that when cc is engaged the box changes down on motorway gradients which otherwise wouldn't have been necessary in normal mode.
I suppose into the equation must factored in the gearbox 'memory' which adjusts to individual driving style.

[Dorchester2]

Originally Posted by clf

Also a practical issue I could see being an issue (to me at least) would be the extended acceleration could be unsettling. After disengagement of the cc, then the resume function applied.

Originally Posted by rovertone

I find that when in Sport mode (which I rarely use) the box doesn't seem to want to shift into 5th gear, I've always assumed staying in 4th to provide the sharper response which is not what cruise control would be seeking to do, in other words working against each other.

Thank you both. That makes sense and we can assume that Rover engineers issued a warning for some reason.

But I'll have another try nonetheless because in all my previous tests the problem of the unsettling acceleration in 4th gear aka the unreachable 5th one didn't hurt me. I don't remember noticing it or it's my memory which is likely failing...

[bl52krz]

Why would you want to use cruise control when in sport mode? Defies my logic of using sport mode. Come to think of it, I have never bothered with sport mode.Kick down seems good enough for me.

[Dorchester2]

Originally Posted by bl52krz

Why would you want to use cruise control when in sport mode? Defies my logic of using sport mode. Come to think of it, I have never bothered with sport mode.Kick down seems good enough for me.

At the first glance your remark looks sensible and logical... but... were you living in South West of France and using from time to time to cross the 'Massif Central' you would be aware that two useful and magnificent motorways have rather steep slopes and even several access ramps hard as well. The engine will be more responsive in sport mode and overtaking for example will be made far easier when uphill. Nevertheless cruise control remains an asset for my poor backbone mainly because then both my legs can relax hence avoiding the dreadful sciatica. Driving so I try to get the best of both worlds...

[patrolman pete]

Back in 2001 when I had my first V6 auto. I asked the dealer if there was a fault with the car not changing into top gear when in sport mode. He said it won't change up until around 100 mph ! I don't know how true it is as I've never checked as the fuel consumption was bad enough at legal speeds !

[rovertone]

Originally Posted by bl52krz

Why would you want to use cruise control when in sport mode? Defies my logic of using sport mode. Come to think of it, I have never bothered with sport mode.Kick down seems good enough for me.

I must confess I had never given kickdown a thought, forgot it even existed so have never used it!! Must give it a try next time I'm out to see if it works. I drive fairly steadily but when I do step on it to overtake I find enough oomph without having to be too heavy with my right foot, the remap no doubt helps.

This now reminds me of my Rover 800 with the KV6 where I frequently used kickdown, that engine was not very torquey at low revs but once you got past 3000 it was wonderfully free revving.
Probably see a bit of black smoke around here tomorrow as I clear some soot out!

[clf]

Originally Posted by Dorchester2

Thank you both. That makes sense and we can assume that Rover engineers issued a warning for some reason.

But I'll have another try nonetheless because in all my previous tests the problem of the unsettling acceleration in 4th gear aka the unreachable 5th one didn't hurt me. I don't remember noticing it or it's my memory which is likely failing...

I tried it tonight on my way home, also since I experiment regularly on this short route, I was hoping to compare notes on fuel economy as well as acceleration. I did not notice any difference in either, except that it did not lock up (which it wont when in sport mode), nor did it drop to coast when I switched it off when reducing speed without braking to a lower speed limit (which again in sport it wouldnt).

When using the resume function, there was no noticeable difference either in acceleration but this was only from 30-50. So it may be that in sport mode, as the revs are held for longer, it may simply be an economy issue.

Incidentally, in sport mode on the diesel, it will go into 5th - I think this is just above 70mph. In my experience, sport mode changes gear when the next gear will have something like 2 or 2,500 revs to start from, therefore maintaining torque.

Originally Posted by bl52krz

Why would you want to use cruise control when in sport mode? Defies my logic of using sport mode. Come to think of it, I have never bothered with sport mode.Kick down seems good enough for me.

I find there is a massive lag when using kickdown, worse if lockup has been activated. Sometimes this lag is dangerous (eg when merging from short slip roads), so when on one of these roads, I will flick it into sport mode, and it holds the gear and gives immediate acceleration without the 'box thinking about what it needs to do. Kickdown is still available too, but I find it rarely is needed.

You should give it a try, I think you will be impressed at the difference. When selected, if cruising particularly with lockup active, the reaction is immediate.

[Dorchester2]

Originally Posted by clf

I find there is a massive lag when using kickdown, worse if lockup has been activated. Sometimes this lag is dangerous (eg when merging from short slip roads), so when on one of these roads, I will flick it into sport mode, and it holds the gear and gives immediate acceleration without the 'box thinking about what it needs to do. Kickdown is still available too, but I find it rarely is needed.
You should give it a try, I think you will be impressed at the difference. When selected, if cruising particularly with lockup active, the reaction is immediate.

So yesterday going to my daughter's I've had another try in sport mode on the whole 50km (31 mls) journey which I hadn't used for a long while.
As everyone knows even you'd ask for cruise control, it can be activated only on request (set or resume) and de-activated when breaking or pushing on resuming. Hence I'm using the CC only on suitable portions of the journey, and not all of it like sport mode yesterday.

First of all - as you told - when pushing on 'RES' the reaction is impressive, immediate and even - if I may say so - a bit harsher than in eco mode.

But when reaching the wished speed - in my case 80km/h (50 mls) which is now the limit allowed on a large majority of roads and consequently a tad less than 2k revs - I swear that I'm back in top gear without the slightest difficulty.

Checking Torque Pro statistics on the whole journey (including the way back) it's obvious as expected that higher revs are used over 3k. With an auto box in eco mode and on 50 mls limited roads it looks nearly impossible to go faster than 3k revs but when doing a kick down.
Mind that among lots of short sections between 3k and 3.6k revs, I even went from 2350 revs at 81 km/h (50 mls) to 6410 revs at 103 km/h (64 mls) in 2 or 3 seconds! But do notice it was on a bypass limited at 110 km/h (68.35 mls)!




EDIT: in the table above consumption figures are wrong. Torque Pro can't adapt itself easily to E85.



In the end I had a fuel-up: on 128.62 mls (207 km) I fiiled 24.60 litres which gives 23.77 mpg (11.88 l/100km) which looks rather good for a V6 2.5 because with full E85 you need around 20% (TBH between 20 and 25% according car, temperature, speed and lots of parameters) more fuel. Hence it's at least the equivalent of around 28.5 mpg (9.9 l/100km) with 95E10, maybe a tad better. But my V6 2.5 is a special one with a few mods (derestricted air box, full derestricted SS exhaust line and a few other ones).




In the end TBH I don't actually need sport mode AND cruise control: CC is enough with some kicks downs when needed.