Quote:
Originally Posted by badbread
Negative, same tune (MHD stage 2) but the difference is very apparent with straight 91 and the E85 mix... I probably fill up once a month and can tell without checking my fueling log if I E85'd or not the previous fill up.
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Interesting... you mean you can tell in the butt dyno and in data logs? I assume this is from less timing being pulled with the straight 91 if you are on the same tune...
I am wondering if the E-mix tunes add additional fueling to compensate for the ethanol, or if they just leave that up to closed loop operation? I don't know enough about the tunes and exactly how the DME is using fuel tables, MAF, MAP, and closed loop O2 operation to make an educated guess. It would be interesting to see if you had a log of straight 91, then a log shortly after with 91+3gal E85, on the same tune, to see if AFRs and fuel trims change. Maybe the mix tunes just add additional timing to take advantage of the higher octane and leave fueling up to the DME.
MHD has full E85 tunes now; have you tried those? I only read about one person in France using them. There was a post from MHD when they first released back in June that "they are the most powerful stage 1 and 2 logs".