BMW and M Power Owners

Tomcat825 said:
One more thing, over 100 miles I averaged 34.4 mpg sitting at 70 with a few hoons, which I must admit, I was thoroughly impressed with. I've since done another 100 or so and over the 200 it is down to 31.5, which even so it is still amazing considering the performance!
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I assume your referring to the OBC readout?

I'd take it with a pinch of salt tbh.

Sitting at 70, it seems to read more or less the same as my e46 325i Touring although doing a brim to empty and refill check, mine is nearer 32 mpg on a run and mid 20's around town.

I'd be interested to see what you get by doing this??

With 300+ BHP on tap with yours, I'd be more than happy too though!!

Looks nice, I'm not sure dark grilles suit a black car though, I have the same on mine but it's a light (ish) blue....
 
Scania said:
I assume your referring to the OBC readout?

I'd take it with a pinch of salt tbh.

Sitting at 70, it seems to read more or less the same as my e46 325i Touring although doing a brim to empty and refill check, mine is nearer 32 mpg on a run and mid 20's around town.

I'd be interested to see what you get by doing this??

With 300+ BHP on tap with yours, I'd be more than happy too though!!

Looks nice, I'm not sure dark grilles suit a black car though, I have the same on mine but it's a light (ish) blue....
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Aye I've never really thought much about how accurate the reading actually was tbh, will have to check it properly as you say.
The OBC on my E46 325i sat between 36-38 on 70mph journies.

Decided I will be changing the side grills and kidneys back to Chrome. The subtle look just doesn't go with an M3 and kinda ruins it imo. :D
 
Got to agree with Fox. Generally my OBC's have been pretty accurate when compared to manually calculating the mpg.

My A4 BE (in fact, all my A4's) was within 0.5, same as my 335d, 530d within 0.5 - 1.0 mpg.

Once mapped though, then they were way off. I wouldn't trust the OBC on a mapped car. Always worth testing it out a few times though, to see if it is off, and by how much, then you can forget about it in the knowledge that you can make the necessary adjustment if you care about such things (which I do).
 
How did the map affect it out of curiosity? E.g. did it overestimate the MPG or under?

Curious, as I've had my 320d mapped and never really thought about the effect on the OBC.
 
It overestimates.

My 1.8T Golf GTI would show around 30 mpg average, and get a 300 mile tank. After a remap, it showed 35 (approximately), but only a 280 mile tank was achievable. Same with one of my mates after he stuck a T3/T4 turbo in his 1.8T A4. He regularly saw 45 mpg on the OBC, but was getting closer to 30 mpg.

That said, my 335d was mapped, and was still within 1 mpg of true figures, so it's not always the case. It is worth checking out though, as I have seen a few remapped motors who's OBC lies post map.
 
Just did some rough-sih calculations, approx 2-3 mpg overstated post remap on my E90 320D.

OBC reads around 47MPG but the 'real-life' calculation is closed to 45.
 
And I now seem to have put a deposit down on that red one I borrow last night...erm yikes ;)

All confirmed picking it up Monday when i get back from Download :D
 
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Anyone had the 5E21 error code? Hopefully it's just the brake master cylinders and not the actual ABS unit.
 
In the e39 (and therefore I'd assume the e46 too) you can adjust how the OBC interprets the fuel flow rate to make the fuel economy read out more accurate.

I guess they all leave the factory with a default setting but there is likely a range of tolerable signals given by the fuel flow meter that whilst within spec cause the fuel consumption reported to be slightly out in some vehicles.
 
PeterNem said:
In the e39 (and therefore I'd assume the e46 too) you can adjust how the OBC interprets the fuel flow rate to make the fuel economy read out more accurate.

I guess they all leave the factory with a default setting but there is likely a range of tolerable signals given by the fuel flow meter that whilst within spec cause the fuel consumption reported to be slightly out in some vehicles.
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Any idea how I do this? :)
 
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