E85 tuning an L61

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10-07-2018
AnthonySoprano

E85 tuning an L61

OK, here's what I have. I'm also BRAND new to tuning, so please bear with me.

04 L61 in a Chev cavalier. LE5 bottom end, L61 head. Stage 3 cams, factory manifolds, factory injectors. I have a mail order tune in it right now for this set up.

I would like to run E85, shave the head, and upgrade the injectors.

BUT, I can't change the target AFR in an 04 Cavalier.

The car is a circle track car, so mileage and cold starts are not an issue. I'm spinning 5000-5200 RPMs on corner exit, and topping out at 7000-7200 RPM on corner entry.

My question is, could I tune the AFR through power enrichment mode? Here's my thought - and slap me if I'm wrong. Could I turn my PE on above 2000RPM, leave my RPM multipliers all at 1, set my base AFR vs ECT all at (whatever value is correct for E85)? I contemplated turning the enable TPS vs RPM down to 10% across the board. In theory, I'm trying to manipulate the correct AFR for E85 via PE mode by enabling PE pretty much all the time (except on closed throttle ect).

Hope this makes sense....
10-08-2018
steelmesh

Quote:

Originally Posted by AnthonySoprano

OK, here's what I have. I'm also BRAND new to tuning, so please bear with me.

04 L61 in a Chev cavalier. LE5 bottom end, L61 head. Stage 3 cams, factory manifolds, factory injectors. I have a mail order tune in it right now for this set up.

I would like to run E85, shave the head, and upgrade the injectors.

BUT, I can't change the target AFR in an 04 Cavalier.

The car is a circle track car, so mileage and cold starts are not an issue. I'm spinning 5000-5200 RPMs on corner exit, and topping out at 7000-7200 RPM on corner entry.

My question is, could I tune the AFR through power enrichment mode? Here's my thought - and slap me if I'm wrong. Could I turn my PE on above 2000RPM, leave my RPM multipliers all at 1, set my base AFR vs ECT all at (whatever value is correct for E85)? I contemplated turning the enable TPS vs RPM down to 10% across the board. In theory, I'm trying to manipulate the correct AFR for E85 via PE mode by enabling PE pretty much all the time (except on closed throttle ect).

Hope this makes sense....

This might be the hack way I am also new to this; from my experience installing 80lb injectors driven by a E67 LE5 ECU, you can trick the computer to do a global change to fueling. If you're going run E85 exclusively in a car setup for gas, then maybe you can use the injector flow rate vs. battery voltage to enrich your fueling everywhere. I would question what happens to the min pulse and injector offset though. You need the computer to flow more fuel because E85 stoich, so then you enter a multiplier that is less than 1 in the flow vs. voltage table, so the computer compensates by throwing in more injector PW. Shot in the dark here, the multiplier at 13-14 volts might be [9.8 / 14.7] = 0.666.
10-08-2018
AnthonySoprano

OK, bear with me. I think I'm following ya.

Wouldn't the LE5 computer be confused because there's no VVT? Or would it just go to a default setting and run anyway?

One issue I can forsee (and I failed to mention) with the battery voltage multiplier. I have a mirco switch on the throttle that controls the alternator. Under (roughly) 50% throttle or more, the alternator is turned off. Under half throttle, the alternator is turned back on. So, when coming out of the corner, the alt is turned off, minimizing parasitic load. When entering the turn, and rounding the turn, the alternator charges when parasitic load isn't a concern. I'd be worried that the voltage drop would interfere with tuning it correctly.