patsmx5

iTrader: (16)

Makes sense. Thank you sir! I'll probably ask more dumb questions on tuning once I get it back together.

patsmx5

iTrader: (16)

Ok so after doing some reading on this, here's what I found.

Nobody tunes for max power rich AFRs on E85, or well, most people don't.

I've found a few cases of people saying it KNOCKS when running very rich on E85 at say 9-10 AFRs (gasoline scale) and leaning it out to say 11-11.5 did not knock and they were able to add more timing and make more power.

My question is, why? Seems crazy that it would knock with more fuel.... Have you ever had a car knock from too much fuel with E85?

18psi

iTrader: (76)

I've heard that too. Nope, never experienced it, and I've had it dip all the way down to 10:1

IMO they probably experienced misfires from running too rich, but it registered on the sensor as knock.

patsmx5

iTrader: (16)

Nope, I've read a few people that confirmed it was knock, actual metal on the plugs under a microscope/magnification lense. Some Supra guy blew a motor doing it on a dyno, melted the piston. Another with 2 forms of knock detection confirmed it too.

A fine gentlemen on this forum kindly pointed out to me it's likely caused by pre-ignition. And I believe it is, but now I'm trying to figure out exactly why adding fuel would induce it and removing fuel would stop it.

My best guess right now is you add fuel, it burns more fuel, which makes more heat/more power (good). More heat causes the electrode of the spark plug to get hotter, leading to pre ignition. (bad).

if this is the case, pulling fuel does "fix" it, but that's leaving power on the table and masking the underlying issue.

I have much more E85 reading to do, but this is where I'm at right now.

aidandj

iTrader: (5)

See paragraph about research octane vs moyor octane.
<br />
<br />What You Need to Know About E85 Ethanol Alternative Fuel - Hot Rod Magazine

18psi

iTrader: (76)

I'm trying to figure out why you always try so hard to overthink everything so much.

lol

patsmx5

iTrader: (16)

That. I want to learn/understand, not just know the "rules" but understand it.

And, because engineer.