Fuel Composition Tuning...Inverse?
 

As I get closer to finally starting up my long term project car, one thing I have been on the fence about it whether to start with crappy 91oct CA pump gas or E85. I found a map from someone here on the forum for PS1000 and ID2000 x4 on E85 that Ive been thinking about using (https://www.rx7club.com/haltech-foru...00-map-947866/). My setup is pretty much identical to his. If I zero the timing it should be good enough to get the car running and use as a base on the dyno.

However, if I use this E85 map as a base, I will not be able to take advantage of my flex fuel sensor in closed loop correction. Correct? I know the recommended procedure per Haltech is to tune a safe base on pump (or 0% ethanol), then drain the tank, fill the tank with E85 and tune only using the composition correction maps...adding fuel/timing/boost based on increasing ethanol %.

Im wondering...Since this is a track car that will not see anything but E85 (the only reason I want to use the flex fuel sensor is just in case I get a low ethanol batch of E85 from the gas station), is it possible to use the correction maps in reverse? Ie. - Tune a base map on 85% ethanol, and use the correction maps to take away fuel/timing/boost based on decreasing % of ethanol. Of course you would have to inverse the scalar maps as well such that at 85% composition it would use 0% of the correction map, and at 0% composition use 100% of the correction.

Any input would be much appreciated.

Thanks.

Yes you can the ECU does not care.

Awesome. Thanks for the info.
I think I'll try it.

I tuned my car using E85 base map and told the ECU to take away 30% +/- instead off adding 30% +/-

Nice. Thanks for the input