[Joshinator99]

Originally Posted by Saberscar223

I’ve been doing a lot of reading and I hear that Ethanol can increase the amount of boost you can run due to keeping the engine cooler but also less boost because fuel systems can’t keep up with it. I’m just super confused on what it depends on? When is it more beneficial to run 93 vs E85 and vice versa?

Is there a point where the boost on 93 would out-way the benefits of Ethanol?

Wow, a lot to unpack here lol!

E85 is ALWAYS BETTER THAN 93… *unless* your fuel system is too small to adequately supply the engine without leaning out (being outside of the injection window). The octane number of E85 is much higher than pump gas so yes, you can run more boost assuming you can move enough fuel…it takes roughly 30% more fuel volume. Running a blend of 93 with E85 can reduce fuel system volume requirements but still give most of the E benefits. For example, the last few years I’ve run E50 which gives most of the E benefit but let my fuel system hang out without leaning out too much lol.

93 will never outperform E, it’s just a matter of making sure you can adequately fuel the engine.