Originally Posted by Ænema
CAT(charge air temps) are the same thing as what we usually refer to as IATs. For me it is more accurate to talk about IATs as pre turbo and CATs as post turbo, but that's just me.
You are correct with your line of thinking, however in application it works a little differently. The DME follows timing correction tables that will target lower timing advance the higher the CATs climb. It doesn't matter if you have 100 octane/e85/Q16 or whatever else in the tank the DME will still target less timing, it does this to prevent the CAT induced knock you're talking about because it assumes you have 93 octane. At that point, all the e85 can do is just prevent timing corrections.
That's why getting the BMS back end flash is a good idea, Terry(probably) makes changes to the correction factor tables to reduce the effect they have.
I see what your saying. What is this BMS back end flash? Is is a special JB4 or does Terry have to actually flash your ecu? Thanks