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      11-14-2012, 03:37 PM   #63
Second Lieutenant

Drives: 335i e92
Join Date: Nov 2012
Location: CA

iTrader: (3)

Originally Posted by bmw335idizzle View Post
So if I'm running 50/50 ethanol:91, I don't really need the Cobb flash? Only if I'm running more than 50% ethanol? Also, you're saying every time I refuel, I should reset back to map 5 so it will relearn my ethanol:gas mixture? U do that by just going back to map mode and choose map 5 right.
You only reset when you go from ethanol blend to no ethanol. If you are always refilling with ethanol and gas then you don't need to reset. So 90% of the time (if the E85 is close) you don't need to reset. The reset is accomplished over steering wheel controls and takes less than 5 seconds.

You may have a car that only runs 30% ethanol, but if that's the case then there really isn't much difference between proceed and jb4. Either one will then require you to buy something else like Cobb or flexfuel kit. I suspect you can run up to 50% though since most people can. You only need about 40% mix fyi to get full timing at ~18psi safety limit.

Whichever you choose though, I advise you start with just the tune. Then you can opt for Cobb or flexfuel if needed. Don't expect the gains to be anything near the 0-50% level when you go from 50-100% though. The bulk of the performance benefit is realize on tune only.