For those of you out there that have differen't ethanol tunes, About how much different are they compared to say e75, e80, and e85? I just tested the fuel I put in mine and it's roughly e80. I'm going to start with this as it's my first fill on the stuff. Just wondering about how much richer I should make it for when I find some e85, as a starting point only.
tune differences between ethanol contents(e80, e85, etc)
- Thread starter ctgreddy
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Most I've seen post say they don't even worry about that "small" of a difference.
I agree, much like tuning on pump gas in which actual octane varies, just don't tune it on the edge. I wouldnt worry about it if the ethanol content varies 70-90 etc.
Thanks for the tips! the big question is I dont know and cant find anything by searching about what to shoot for. I just went and did a good 3-4 wot pull and lambda was .70-.73 which seems a little rich but dont want to get too aggressive with it.
you are in an entirely different arena with ethanol. There is no comparison to pump gasoline crap. .70-.73 is too rich. Lean it out to about .78-.79 should be around the sweet spot. You are NOT going to detonate, not even close. You could probably go 1.00 lambda and never detonate in a bazillion years. Not that that is advised..but just demostrating how vast the safety zone is.
i was told that you need to be tuned on true E85 so when you go to the pump and get a content that is off the computer wil adjust and your car will just run rich , its my understanding you would not want the opposite being tuned on ethanol content that was lower and you lean out when you get a higher content. Also from my understanding the octane rating of e85 is not affected unless the ethanol content was below 51%.
I know the whole deal with tuning on E85 then running on a lower % should cause you to run rich. But with these cars shouldn't the computer trim out the fuel to keep the correct lambda regardless? Or is it that it can only adjust to an extend?
I've always wondered this.
I've always wondered this.
The ECU will adjust when you are not WOT. This can be seen with the short term fuel trims. However, when you go WOT its going off a fixed map and the O2 sensors are not used.
Are you sure that's the case with our cars? I know that cars with narrow band o2's operate like that but I though with the wide bands they stay in closed loop during WOT because the computer and o2's can adjust fast enough.
I know during WOT I see my trims are constantly adjusting in the log.
I know during WOT I see my trims are constantly adjusting in the log.
Oh. I assumed you had a 99-04, oops. Not sure about the new ECU in the '12.
I forgot too that this is the distillery and not a year specific category.
Anyone know how this applies to the coyote motors?
Coyotes are always in closed loop. They receive constant fuel adjustments unlike the 4.6s.
You're correct. the pcm in the coyote's will try and maintain a certain lambda at wot. Thus why on a nitrous coyote you have to have an actual nitrous tune instead of just pulling timing out of an n/a tune. As the car see's the nitrous on(the fuel jet will be spraying) it'll take that extra fuel back out. I'm not sure how quickly it'll correct to a certain reading, but that's how it works in theory.
They correct pretty quickly.
The older cars however just run in open loop at WOT so a change in ethonal content can throw the AFR around .1-.2
As long as you don't have it on kill it's not the end of the world.
However I wouldnt say that it's OK to go crazy lean on ethonal. As you start getting crazy with power you can still melt things on E85
The older cars however just run in open loop at WOT so a change in ethonal content can throw the AFR around .1-.2
As long as you don't have it on kill it's not the end of the world.
However I wouldnt say that it's OK to go crazy lean on ethonal. As you start getting crazy with power you can still melt things on E85
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