I'm wondering if it is worth running E85 for 300whp on 8.6:1 pistons or if 93 will be sufficient. I live in Iowa, so the corn juice is abundant, plus I already have the injectors and pump for it. Also, is the stock fuel rail/FPR/fuel system in general good to use with E85 as long as I don't let it sit for too long?

 

Put a new fuel filter in, but yeah. Run it, add some timing. Enjoy some more power.

 

At only 300whp, 93 octane would be more than sufficient. Unless E85 is cheaper to run or there is some other benefit you're looking for I wouldn't bother if you intend to cap the power there.

 

Agree, many factory turbo cars like EVO and Nissan GTR run similar compression ratios at similar specific power levels, on the lower octane gas, so should be fine.

 

Don't mean to hijack the thread, but is the stock Miata fuel pump compatible with e85? Been thinking about adding in a flex sensor for some learning. E85 station is like 5 minutes from my house.

 

I believe so, but you MUST change your fuel filter for sure. Ethanol is going to take 30% more fuel for the same power level, so you’ll need injector and pump for that much more fuel, probably just worth upgrading.

 

Yeah, I was gonna change out the filter too. I got 640cc injectors as well so yeah I'd probably need a pump upgrade eventually.

 

Fab9 has DW pumps in stock right now, the walbros are out of stock pretty much everywhere. I just got a DW200 and called it good.