Thread: NA air fuel ratios

E85 DOES NOT like running lean. Run more advance, but keep it a little fat. Otherwise you will melt things. E85 relies, in part, on the extra fuel to keep temps down and raise the MON and prevent detonation. I would never suggest running leaner on E85. I've seen too many ppl have issues.

With tuning my setup ive found that any excess fuel drematically affects the engine!!! its very very sensative to fuel.

This could be because iv'e got a well ported and extreme port setup with well sorted runner width etc. Air velocities are probably up so any excess fuel just kills the burn!

I noticed int he vicinity of 10kw power difference of 11.1 to 12.2. right across the range. This wasnt even playing with timing!!

You running E85? Every tune I have seen running E85 has shown that there really isn't much power loss running rich like there is with Gasoline. You can run a 10:1 AFR and run really strong, where gas would create fouling issues unless boosted. Half the merit of running E85 is the fact it cools the a/f charge because of the extra fuel.

But just like Gasoline, I've seen engines melt down when run too close to the edge.

by lean i meant you may see better performance with 12 to 1 ratio on na with pump verses seeing better performance with more timing and say a 13 to 1 ratio on e85 ive seen many ppl go one way or the other to make power however it really depends on the cr ratio cams ect as to what is going to work best

True. Just figured I would give a heads-up. Guys around here are finding that lean is not the way to go with the stuff. Couple guys ran mid 12s AFRs and melted things turbo. Of course NA you can run leaner, but I would rather make more power with timing rather than running too lean. Too far either way is not good, but running lean on the ethanol basically offsets what makes it such a potent fuel for performance.

I have jwt s4 cams, bored maf, intake, and header. My stock fpr was causing me to run in the 16.0 afrs, after i installed my nismo afpr i bumped the psi up to 42 and have been in the low mid 13's since......i still need a tune.

this is with a 9.5:1 cr de with bkr6eIX spark plugs.

very true, alot of the times the differences between being lean or rich is minimal power loss. maybe you loose 30whp but keep your engine running alot long

There are two stations in phoenix that has e85. i believe 57th and olive (right across from GCC) there is a station called Z's that has E85. Im not positive where the other one is. right now its 2.37 a gallon i think.

Anyone with experience of tuning on E85 will kow there is a really wide fta band that an engine makes top power on. Not Like pump gas.

true! and specially while on boost, it just takes a second of being lean to blow or melt something...
Personally I prefer to lose a bit of whp but gain reliability... My boosted setup has always been between high 11s and low 12s, and the whp numbers werent bad...