Th biggest difference I found in going from 11.3-11.8 to 12.0-12.3 afrs on E85 is that my plugs last much longer on the leaner mixture. Also, being on stock ignition, I would start breaking up after about 31-32 psi on the rich mixture but have pushed as high as 35 psi on the leaner afr's with no break up what so ever.

 

i noticed about 15whp difference uptop going from 11.7 to 11.9 or was this probably weather induced? i was told to tune for 11.8 and 12.8 at spool from a very respected tuner. i noticed more torque with richer a/f at peak torque also.

 

Bumping this and have a question, I’m in arizona and sadly they have down graded ethanol stations to a minimum 51% and I’m testing about 50-55% which is a bummer. My question is. I’m going to be switching over on my stock setup with fuel supporting mods (walbro 450, and fic 1650’s on stock turbo. (Trying to max out stock turbo) what AFR should I be targeting with a 50% mix E50, I have tuned e85 on my dsm previously, and it seemed to like a 12.5AFR. But I dont want to be too lean being that I have less ethanol content to work woth. But anything is better then 91 oct. all help appreciated

 

Wholly necro post Batman!
This SOB hasn’t seen action in 9 years!!!!

to answer your question.... I used to mix my fuel 50/50 with my direct injected LNF 2.0l and I had the best knock prevention at around 11.5:1 gas stoich ratio.

 

I was tuned on 85 and the AF is around 12.0 - 12.2 . I was actually wanting to know of that was good or not. I know on pump gas I was tuned for 11.3.

Car feels great.

 

12-12.2 is fine for the street and will make good power. If you plan on tracking, its better to be a bit richer.