[TEALSQUEAL]

Nice numbers NA. High compression would benefit from the higher octane rating of e85, but the real difference between FI and NA benefit of e85 is in boosted application from reduction of mixture temperatures entering the cylinder. This also helps the knock on boosted applications. I always love seeing tunes of taking the timing past mbt and then backing it off a few degrees and not worrying about knock. (all on the dyno)

I personally would love a 9.5 compression boosted application. I'll never forget my buddies 11:1 b18 w/3076, it had power everywhere and would easily do 60+mph burnouts w/quaife LSD and 225's

Originally Posted by xpertsnowcarver

This is my comparison of 100 octane vs E85


There is some benefit for NA engines, especially if you are high compression. But, it makes a huge difference for FI engines.

Engine is an Autech S15 SR20DE
11.7:1 CR
444CC OEM S14 SR20DET (Originally 280CC)
Walbro 255
300ZX Fuel Filter
Tomei S-Type FPR

I've been using E85 on this engine for well over a year. The first year was track use only. For the last six months, I've probably put 5000 miles on the engine for regular driving.

No, you do not require more frequent oil changes. I drove 4000 miles (using Motul 300V 5W-30 oil), and the oil looked and felt like any other time I changed the oil. If you're oil is getting broken down by E85, you're piston rings must be letting too much E85 through and/or your crankcase ventilation sucks. Somehow condensing E85 in the crankcase and getting stuck in the oil? Not possible. E85 (like gasoline) has a natural tendency to evaporate at atmospheric pressure. So, E85 would have to be leaking through to the oil.

The only down side to using E85 (to me anyway) is that you don't get any of the additives that promote lubrication in the combustion chamber. So engine wear is going to be a bit higher.

There is a limit to how much compression you can do. I can still manage to get a high knock count on the track with E85. (Side note... I'd assume you'd HAVE TO use race fuel to use the Tomei 2.2L 13.1:1 Stroker Kit). With 91, I was knocking at idle. I'm not going to pay $8.50+/gal of 100 octane... So, if you're turbocharged and want to increase your compression ratio because you're using E85, I wouldn't recommend going any higher than 9.5:1. Maybe 10:1 if you think you're engine is bullet proof.