52,000 mile re-dyno with greddy TT

phunk

More timing doesnt mean more HP. Correct timing means more HP. So for whatever fuel you are running, to run the correct ignition timing will yield the best results. E85 requires more timing, or you will actually lose power from gasoline. So I wouldnt say that the fact you can run more timing gives it any better HP. For any fuel at all, too much timing starts to reduce power just before it blows up your engine. For whatever fuel you have, your goal is to achieve peak cylinder pressure at a specific crank angle which will be the same for any 2 identically built engines. How much timing advance is required to land at that crank angle is a factor of many things but mainly the burn rate of your fuel... but the best you can do is hit that correct crank angle.

I think that the advantage to E85 lays solely in its knock resistance and cooling, and thats about it. Any stock VHR running the same boost pressure as me from the same turbo kit, is pushing the same airflow, and will make the same power if the tuning is correct. The question is, is combustion going to be stable enough to avoid knock using premium pump fuel. I cannot answer that, since I havent tried. 9psi isnt much, but the compression ratio is pretty high. To make better HP at lower PSI just means that my engine is able to run more efficiently while retaining stability. My Greddy 20g turbos are probably larger than most of the smaller stage kits, already aiding that, and the E85 fuel allows me to tune the engine more efficiently because it remains stable. If I moved to pump gas, I would probably have to run the engine quite a bit richer to keep it cool and stable, therefore reducing efficiency, and thus requiring more airflow, more boost, to make up the power. I might also have to run less than optimum ignition timing advance to reduce burn time and increase combustion stability.

I am sure that with all the tricks and techniques, somebody can match long term HP with me using regular pump gas. I let my A/Fs hit mid 12's on gas calibrated gauge... I can run optimum ignition timing for my fuel because the fuel is stable. Between water injection, running the engine rich for stability, conservative ignition timing, and then more boost... I am sure my numbers are easy to match, I just dont know about making as much at as low of a boost pressure. But if you have boost to spare, then it doesnt really matter what that boost number is.

I will add that everything I say is based on very limited research into E85. Most of it is just gut feelings and impressions based on my experience of running it just one car, my own. I used to dyno tune cars every day when I had a dyno, but it was a lot easier when there was only high or low octane. Now with E85 its entire dynamic is all different and the numbers and curves are vastly different than gasoline and since I dont have the motivation to deep research it, I just use my feelings on it. Anyone who knows EXACTLY what is going on in there, is more than welcome to come school my ***. I am one or two steps from the furthest thing from a full time engine management tuner.

I have 19x11 with 305/30/19 R888s and 18x12 with 315/35/18 Toyo TQ. Neither setup has good enough traction to lay down the law.

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