Another MPG thread E85 vs. pump fuel (my tests this weekend)

[JayRolla]

Originally Posted by wishihadatalon

Remember that the magical number of 14.7 or stoich is when a flame burns hottest. Running it leaner will probably just cause misfire issues and a loss in power. Given the slow piston speed and low cylinder pressure at cruise, I would say that your ignition timing would have to be pretty messed up to burn a valve while cruising or do any other internal damage.

So your saying I can pretty much run as lean as I want at cruise and the motor will be 100% fine, other than mis firing?

[wishihadatalon]

Originally Posted by JayRolla

So your saying I can pretty much run as lean as I want at cruise and the motor will be 100% fine, other than mis firing?

[Diy_efi] Lean Cruise some good stuff there.

[selmerguy]

Originally Posted by JayRolla

So your saying I can pretty much run as lean as I want at cruise and the motor will be 100% fine, other than mis firing?

Not "as lean as you want" But more lean. I like 16:1. it works great. The way I have my car tuned it will cruis like that all the time. But when I put the pedel down the tune changes automatically and I "normal" AFR's under high load.

[polarmoment]

i get about 18-20 city and mid to upper 20's highway on E85 in my MR2.

i run 16.5-17 AFR (gas equivalent) at cruise, and i keep it as lean as 13.5 all the way up to about 5psi, which helps spool the turbo, but also keeps the ECU from dumping fuel whenever you have to give it enough throttle to get near atmospheric manifold pressure (accel pump). i haven't had any misfires with it yet, and the plugs look great.