allblowdup

I just realized that my engine was set up to run 31 deg timing at 23lbs of boost on e85. really seems like a lot to me. any thoughts?

JoeNova

Your username is fitting

rpturbo

iTrader: (47)

I can't speak about E85 timing. A good rule of thumb on gas is the 28 rule. Max timing 28, then subtract 1* for every pound of boost, so 14#'s of boost @ 14* is GENERALLY safe.

_Adrenaline_

iTrader: (4)

The amount your engine tells you is too much. But seriously all combinations are different you cant just take a timing number that worked for someone else.

turbolx

This is what a load bearing chassis (or engine) dyno is for. Since E85 is such a high octane fuel, knock is unlikely in most cases. This means it's entirely possible to over-spark the engine (losing power due to increased pumping loss) even if you don't get knock. The only way to tell where the "right" amount of timing is would be to take a torque/power measurement. This is best done on a dyno where you can collect this data under controlled conditions across the whole RPM range.

JoeNova

31 degrees might be okay at 10k RPM.
Very very very few situations where you'll get away with that much peak timing at less.

allblowdup

All the answers seem to agree with my thought that it is too much. I will keep checking as it was tuned on a dyno.

Old Geezer

iTrader: (3)

Any thot of looking at plug readings?

ddnspider

iTrader: (26)

With access to a Dyno, make a pass at the track or "at the track" and look at mph or time from 1 speed to another. When you stop picking up big chunks of gain, you're close to peak timing.