[martinjohn212]

okay, i know there are plenty of threads on here abotu mpg before and after remap, but many are conflicting.

I just need an honest opinion

I have a 325D m sport, e92, done 76K miles, i bought it around 2 months ago and was achieving around 46 mpg, and got 53 mpg driving birmingham to london.
The car was due a service.

I have had the car serviced fully. Oil, oil filter, air filter, all micros aswell.
as well as this i had the car remapped to 266bhp

I Expected the mpg to drop to mayeb around 40.

but i am strugling, really strugling to get 35 mpg on general driving, and on a trip from hertfordshire to bristol and back the next day i only averaged 38mpg over the 200 miles of crusie control set to 85.

opinions on this please?
much appreciated!!

[makkan00]

Originally Posted by martinjohn212

okay, i know there are plenty of threads on here abotu mpg before and after remap, but many are conflicting.

I just need an honest opinion

I have a 325D m sport, e92, done 76K miles, i bought it around 2 months ago and was achieving around 46 mpg, and got 53 mpg driving birmingham to london.
The car was due a service.

I have had the car serviced fully. Oil, oil filter, air filter, all micros aswell.
as well as this i had the car remapped to 266bhp

I Expected the mpg to drop to mayeb around 40.

but i am strugling, really strugling to get 35 mpg on general driving, and on a trip from hertfordshire to bristol and back the next day i only averaged 38mpg over the 200 miles of crusie control set to 85.

opinions on this please?
much appreciated!!

Remap does inject more fuel into engine AFAIK to get more acceleration.

So thats not bad to start.

The logic behind increased MPG after remap is getting quick acceleration and then cruising most of the time. Cruising does help to improve mpg.

However CC at 85 does not help at all.
Set it b/w 60-65 and you get best results.

That is what I have gathered from experimentation and learning from other's experience.

[Icekube]

generally a remap will improve fuel economy, as you need to use less throttle to get the same power.

who done the remap? it could just be shoddy?

[ArsE92]

Sounds like a crud remap

[AWSAWS]

wind resistance triples with a doubling in speed I think.

My mpgs are exactly the same post remap (well JB4) on a 335i, but then the JB4 is fooling the car with how much boost it's running so maybe it's not fully accurate?

[martinjohn212]

Hmm see im not to bothered by mpg, but it seemed extremely low, as have seen people in petrols get similar, was thinking maybe something is wrong, air filter chamber not put back properly after service?
I had it remapped at a well renowned bmw tuning garage, dont want to release name until i spoke to the garage, but wanted opinions and thoughts from you guys and people who have had a 325d remapped

[Hulla the Hulla]

Crap MPG ? Check your engine temp to make sure you're running at 90 deg or more. Could be thermosat issues.

[old grey steve]

Fuel economy v performwnce is a tough one we re map and overall everything is good but we have seen the odd one where you'll honestly get a blip in usually in economy. Power wise no one really says anything else bar the powers more noticeable, but economy yes from time to time on the odd one can come up fir discussion.

As makkan stated how you measure your fuel economy figure with cruise set at that figure may have an effect on the outcome you're seeing with cruise on at the speed you're traveling at the map for fuel would of been altered and perhaps St certain inputs fuel/air ratio figures may effect the result you're seeing, if perhaps you look at the broader spectrum of economy v power increase you have achieved what would be the difference?


But all things being even the first tthing I'd say we would do is if a customer had an issue re a certain area would be to do a full diagnostic on the car to check everything re the engine, coolant temperature etc. is perfectly OK and that nothing else is causing in your case the fuel economy issue you've highlighted.

The idea of having a re map and altering the cars torque curve/power delivery means that you'll get a broader flatter power delivery across the cars powerband, you'll discover more power at lighter throttle inputs than say you would do with the standard car.

We could have say 3 identical cars in re map them all the same way yet get 3 different results. Why? Well it could be a number if different reasons why.... But if a customers doing the same journey and see's a difference in economy post work then perhaps as a garage(In Hertfirdshire that re maps)100% we'd look listen and find an solution.

If a particular result has occurred on a particular vehicle we would actually after doing a diagnostic and see everything vehicle wise is OK will look at the map very closely. If a particular element of the map has/is creating a 'conflict'then we'd address this area by re aligning the map to counteract the issue you're facing.

All I can say is have a word with the garage who carried out the remap to see what assistance can be offered.