I’ll just say it again as it’s mentioned a bunch of times already. Your AFR is lean as hell for E85. 12.0 is even lean for boosted gas motors. Why aren’t you in the 7’s? That’s where a .78 lambda would be for E85. Last I checked stoic is 9.7 for that fuel.

I’d wager you could get more timing if your fueling was on point for the fuel.

 

No. Gas scale . 11.8 afr at 15 psi boost and 11.5 afr at 25 psi boost is where I shoot on these builds . I’ve just noticed if I’m under 20 psi boost and lean it out toward 12.0 I almost always see an improvement in mph at the stripe provided the rings are gapped for this .

 

No offense, but you're confused/mistaken and shouldn't be giving advice.

Max power rich on E85 is .86
Max power lean on E85 is .71

The sensor reads lambda and converts to a gas scale on your gauge. It doest care what fuel you run.

If you have a gas scale gauge:
.71 lambda is 10.44 AFR
.86 lambda is 12.64 AFR

So you can literally be anywhere from 10.4 to 12.6 on that gauge and be "ok". What AFR the motor likes will depend on the setup/location.

 

 

That makes sense with a gas gauge. Sorry if I misunderstood, was just saying the straight stoich numbers for that fuel are indeed much lower. I didn’t read into this enough to catch the type of gauge. Makes sense with conversion.

 

I'd only be reading the plugs for timing, I'd be using data logs for the AFR correct?
I'm not a hard core race guy, just an occasional weekend warrior.

 

Yes and I fixed it for ya.

 

I'm just learning how to tune so AFR has been far easier for me to acclimate to, Lambda is just weird, I know its better though lol.

 

Its easy when you realize it doesn't matter what you use, just have a chart handy and you can use any scale you want.

 

if you are just learning AFR...stop.

I started learning on AFR years ago then learned about Lambda shortly thereafter. At first it was confusing because I wanted to refer back to AFR to what the ratio was.

Stick with Lambda, unless you are tuning 100% pump gas, it's much easier.

 

Those are very handy charts Slow Sedan, thank you!

I'm tuning with pump gas and race fuel which I think the difference is pretty negligible from what I've read.
Wish I E85 around but I gotta work with what I have available.
Now if I was to convert to Lambda, I'd have to adjust my wide band and redo my tables in HP over to Lambda correct?
I don't think this would be too much work, just modifying the equations in HP Tuners, I'd have to find out about the wide band.
Didn't mean to hijack this thread so if I need to start another to discuss I can do that.

 

When people talk about the wideband AFR readings of ethanol vs gasoline they make it so much harder then they have to and then go on about Lambda and how it's the only way and that just confuses more people.

If you only remember one thing you will have no problems at all... Most widebands are setup to show a gasoline AFR scale and when using that shoot for basically the same numbers that you would on ethanol as you would on gasoline and that goes for whatever mix of ethanol you are running (ie target 14.7 at idle/cruise and 11.5 for WOT or what have you). All O2 sensors read in Lambda and then convert to an AFR using whatever fuel you select but seeing as how the desired Lambda for gasoline and ethanol mixes is basically the same it doesn't matter. Just leave the wideband on the Gasoline AFR selection or put it in Lambda if that makes you feel better but it's the same results and you don't need a chart.

 

Ended up getting a couple runs in on Saturday. Air was good . Track was good I added fuel to get it in the low 11s afr like 11.1. 11.2 ish . Lost a tenth and 1 mph from previous runs in worse conditions so back to upper 11s I will go .

 

Did you add timing to use the fuel?

 

Have it ramping from 16 at 6000 to 17 at 7000. Usually a good power but safe area I run on e85 . I’m not just going to throw much timing until I get an idea what part of the combo it doesn’t like . Going to check my timing with a dead stop and make a timing pointer befor anything.

 

Problem found ! Made a dead stop and checked timing found I was 5.5 degrees retarded from the table so my 16.5 was 11 degrees hahaha that explained it . Changed my trigger wheel from 84 before tdc to 78.5 before tdc and she is right on the money. Ready for some more test and tune.

 

Cool that you checked and then shared the info.

 

Are you running the Holley EFI? Or did you physically re-clock the trigger wheel?

At any rate it ought to wake up big time! Prob run better everywhere. 😊

 

I run the megasquirt gold box . Made a timing tab and used a dead stop to mark tdc. Then had to go into my trigger settings and move the # 1 cylinder timing value down started at 84 btdc ended up at 78.5 btdc to get it right on . Should run a lot better now my previous runs were 11 degrees timing . Lol

 

Ah! Nice feature. Beats adjusting every timing table then having to remember you did that!

Now the question is, is the reluctor wheel really mis clocked that badly? 😊

Look forward to the new drag strip results. In the spring?