jetttstream

iTrader: (7)

Your truck is naturally aspirated right?

If I understand how you are using e85 (e70-e80 from pump)

You are using a lambda of (10.4 afr/ 12.0 afr) = .87 lambda or (1/0.87) = 1.154 eq ratio (your PE table setting), Correct?

I don't think my math is right above, but how exactly are you calculating afr? Are you still using gas as a stoich in calculations?

I can't see how you can have a stoich of 10.4 and afr of 12.0. That would be the equivalent of running 14.68 afr gasoline and going WOT at 16.50:1 afr.


I was told by a few e85'ers that they liked to shoot for .80-.82 (nat. aspirated) and go a little rich at WOT and saw great results vs leaning it out due to the extra oxygen content in the fuel. I have not tested this.

What do you think? How is your mileage in the truck? Any cold start issues?

On my truck naturally aspriated I am running .84 lambda (93 octane) in PE. (1/.84) = 1.19 eq ratio

.84 x 14.56 (my stoich point) = 12.23 afr

I will also add I am running an AEM wideband in the lambda setting so I see 1.00 at idle (my stoich point) so if I switched to e85 I would potentially still see 1.00 on the different fuel. I just don't understand where 12.0 on e85 comes from.

-Mike


edit. If I think about it. Your wideband must be in gasoline setting, so 14.7 on your gauge actually is your 10.3-10.6 e85. So in terms of lambda you are actually 12.0/14.7 = 0.816 lambda with an EQ ratio of 1.225 in your PE table. Thus you would see 12.0-ish on your wideband at WOT.

Now it all makes sense. I hope. Essentially at WOT you are actually at 8.49:1 afr if you had an e85 wideband o2 per say.

KLUG'S SS

iTrader: (6)

That's exactly why I tune with Lambda and not AFR and try to encourage people to tune using Lambda because no matter what kind of fuel you may have in the tank Lambda is Lambda period. When dealing with all of these ethanol blended fuels these days especially, AFR just makes everything that much more confusing.

Area47

i am used to using afr as a reference and 90% of the populous is as well.

jettt. your edit got it. it started the other day in -15 degree's just fine. i get about 16-17 on the highway on e85

different approaches. same results

jetttstream

iTrader: (7)

Yeah I definitely left mine in lambda for that reason too

Area, wow -15, interesting!!

JennaBear

iTrader: (3)

Ran e85 in my last two tanks on my Denali.