diesels, what have you done to improve MPG?

[dattrike]

Originally Posted by wuzerk

Good, just in time for the Winter. Let us know your results.

Just did a run from home to Gloster hospital to see my dad,
about 12 miles on A roads (50 MPH) and a little town driving.
Came back up the M5 with cruise set to 74mph (true 70mph)
a bit more town driving, round trip of about 30 miles in all,
Temperature was 85C to 91C on obd on dash, averaged 47.9MPG
on computer. (compared to earlier reading of 39.2 MPG).
Not definitive I know, but very encouraging




.

[Kearton]

In answer to the original question, no body has so far mentioned:-

• cleaning the MAP (not MAF) sensor, see this thread;
• cleaning the MAF sensor (although reports are that any improvements seen from this are short lived); or
• possibly removing the roof-rails on a tourer. One comment suggested that this might save 5 mpg. I've yet to try it.

There seems to be a lot of variation between cars. I can understand a difference between: manuals and automatics, saloons and tourers and possibly between Rovers and MGs (due to tyres & suspensions), but it seems to be much more than the expected natural variation which suggests to me that either:-

• some items are not set-up or perhaps not manufactured consistently,
• other sensors are affected or
• another factor is involved, e.g. a tendency for the brakes to drag.

An obvious question is whether the BMW models with the same engine see as much variation.

Regards,
Kearton

[Ian G]

I have seen an improvement on longer runs (motorways) of around 20 miles to the tank since fitting sideskirts and front splitter.
Ian

[Jakg]

Originally Posted by Colonel Mustard

You mean that 9pm is not a true temperature reading?

The scale isn't linear - 9-o'clock position means anywhere from 75° - 115° C. MGR thought that a fluctuating needle might "alarm" drivers so made it useless instead... your engine may run at 74° C and look fine, despite being way too cold, and the second it goes over that mark it's 115+° C which is waaaaay too hot.

Originally Posted by Kearton

possibly removing the roof-rails on a tourer. One comment suggested that this might save 5 mpg. I've yet to try it.

If the roof rails were mounted across the car (rather than along it) then it would increase drag, but I highly doubt that it'd be a 5 MPG difference!

Originally Posted by ncfc1950

I have seen an improvement on longer runs (motorways) of around 20 miles to the tank since fitting sideskirts and front splitter.
Ian

No offence, but if anything I'd imaging a splitter would create a (marginal) amount of drag... even if it did improve the MPG, I doubt it would be anything noticeable (20 miles per tank sounds very VERY optimistic).

[philjudo]

Originally Posted by James.uk

Speedo reading 68 is approx 61 mph....

Do the maths, how much are you actually saving per hours driving??

And how many extra hours are you on the road for??
..

Dont think my speedo is that far out on 18" wheels. Your MPG I think is probably 95% controled by your Right foot. My MPG is give or take like yours,Maybe a tad more as its manual.

[crofts]

Originally Posted by Colonel Mustard

I'm in a similar boat.

I was getting 45mpg consistently on the motorway run. I've cleaned the EGV/PCV and hope that they will improve it.

I also pumped up the tyres which were only 28psi - so that should claw back a little economy.

My next job is to use this stuff:

http://www.powerenhancer.co.uk/produ...l-fuel-cleaner

Which has a great reputation for really cleaning out the engine.

My goal is to hit 50mpg on the motorway cycle. That should be achievable, I hope.

Difficult with the auto. I find it varies quite widely and can only put it down to changing weather conditions.
Just recently I have had it at 44-45 on computer (42-43 actual) but that is unusual. It's usually 38-42 actual. All motorway, cruise on 78 speedo, 70 actual MPH

[paulmariner]

I usually average 45mpg on a run, about 30 round town.
When I drive to S France each year on 80mph motorways I average about 40mpg. I'm happy with that!

[sikelsh]

My Tips

1) Ensure you drive with Econ on and not Auto, auto will enable the fan, which will reduce engine temperature by about 10Deg, so you could have a good working stat and still show 78 degrees or less.

2) Air intake mod, that seemed to make a difference to me.

3) Nitrogen in the tyres, recently had this put in, dont know if it works yet, will see if it makes a difference .

4) Dont boot it

[HarryM1BYT]

Originally Posted by ASMOTORS

New Dula MAss Flywheel, Clutch, Master Cylder and Slave Cylinder, believe it or not. The power has been restored. The DMF is designed to help maintain power.

The DMF is only there to smooth out the shocks in the transmission of energy from engine, through the clutch, to the gearbox. Really the equivalent of a cush drive on a motorbike. It does nothing to help maintain power, in fact the DMF will translate a tiny amount of the power output into heat within the DMF.

[HarryM1BYT]

Originally Posted by Kearton

There seems to be a lot of variation between cars. I can understand a difference between: manuals and automatics, saloons and tourers and possibly between Rovers and MGs (due to tyres & suspensions), but it seems to be much more than the expected natural variation which suggests to me that either:-

• some items are not set-up or perhaps not manufactured consistently,
• other sensors are affected or
• another factor is involved, e.g. a tendency for the brakes to drag.

An obvious question is whether the BMW models with the same engine see as much variation.

Regards,
Kearton

No two identical cars will ever produce the same mpg figures. There are so many components which can vary and still be within the manufacturers tollerance limits. One of the two might have been lucky and got fitted with all of the components which make it produce the best mpg and the other might have been fitted with all of the components on the extreme edge of the tollerance limits. On top of that, the treatment, maintenance and driving of the car will make a difference too.