Boost and Timing - E85/94 mix vs. 100 Unleaded

[Speed_Dreamin']

I'd like to run around with a bit more boost and timing this summer in my '87. I don't think I want to splurge on an alky kit just yet, and I don't want to be constantly changing plugs and O2 sensors from running leaded fuel. I'm trying to understand what I may be able to get out of a mix of E85 and 94 octane (probably 30/70 mix or so, yields approximately 97 octane) or straight 100 unleaded. I currently run 17 psi and base timing settings on my TT chip (I believe 18/20 degrees) with straight 94 octane. I've never seen more than 1.0 degree of knock. Car has a TA49, 009 injectors, hotwired Walboro, stock location stretch intercooler, 2.5 in charge pipe, 3 in DP and 2.5 in dual cat back w/ out a cat.

From your experiences, what boost and timing might I be able to run on the fuels listed above?

 

[vacuum 6]

I use to run 100 and a 93 mix = ~96 octane on 24 psi/timing with min issues. Run your mixture and turn the boost up slowly...watch the 02s and knock.

 

[Speed_Dreamin']

I use to run 100 and a 93 mix = ~96 octane on 24 psi/timing with min issues. Run your mixture and turn the boost up slowly...watch the 02s and knock.

24 psi and 24 degrees of timing on 96 octane!? Wow. The times in your sig for 100 unleaded on stock motor, is that stock turbo, injectors, etc?

I hope to have my car back up and running soon. Once I run a couple tanks through to wash out the winter storage fuel (it's gonna kill me to stay out of the boost for a while), I'll start trying different blends.

 

[GNVYUS 1]

Someone posted some good tech info on the minor downfall of mixing E85 and gas, it lowered the octane more than the calculations came out too.

I would stay on top of your injector Duty Cycle, knock and Air Fuel Ratio. I am not sure if I trust the Scanmaster in this regard with the mixing of E85, a wideband would be best to find the right mix to give you the proper AF/R.

 

[bsdlinux]

Someone posted some good tech info on the minor downfall of mixing E85 and gas, it lowered the octane more than the calculations came out too.

I would stay on top of your injector Duty Cycle, knock and Air Fuel Ratio. I am not sure if I trust the Scanmaster in this regard with the mixing of E85, a wideband would be best to find the right mix to give you the proper AF/R.

E-85 acts like 105 but trust me is better than 105 for the simple fact that the cooling effect is greater than the race gas equivilent.

I've been using the narrow band sensor just fine for E-85 for over 10,000 miles. There is no reason to make running E-85 harder than it is.. there is no black majic too it. Yes a WB is better in any case gas or alcohol

I've been running an effective E-70 mixture buy mixing some 87 with the E-85 and run 22-23 lbs of boost with 26 degrees of timing


HTH

 

[cjmatt]

well the first time I ran e85 in my car, the check engine light came on before I was even done filling it up (it was running and almost on empty)

The code it flashed was for a lean 02 reading, so do the o2s not account for it then?

 

[bsdlinux]

well the first time I ran e85 in my car, the check engine light came on before I was even done filling it up (it was running and almost on empty)

The code it flashed was for a lean 02 reading, so do the o2s not account for it then?

What was your BLMs? What chip, injectors, etc were you using?? Please tell me you didn't just fill up with E-85 and not have at least an E-85 in the ECM

 

[cjmatt]

What was your BLMs? What chip, injectors, etc were you using?? Please tell me you didn't just fill up with E-85 and not have at least an E-85 in the ECM

you really oughta shrink ur sig pic...way too big

and no, i dont have an e85 specific chip, Ive got a maf translator pro with wideband a/f tracking, it took a little bit of fuel to get it back in the zone, about 17% at idle. I still thought it would at least be close at idle

 

[50Bucket]

O2's wont account for the whole difference, it'll be more then 15-20% leaner, I'm not sure of the window for rich/lean is for fuel trims. I ran it mixed in my Focus a couple times as an experiement to try & help troubleshoot a problem. I was always running between 17-23% rich, so I put E85 in, 3-4 gallons and the remaining 6-7 gallons 93, it was up to 0% now, so it did lean out, possibly even sometimes higher then 0%....