Air fuel ratio E85 TVS

[mackdog2008]

So I had my car on the dyno yesterday, 1st time since I have been running E85 (which is actually E70) for over a year.

Made 728 RWHP and 624 RWTQ !

Last time on 91 I made 633rwhp and 558rwtq

That's on 10.8 pounds of boost

The shop that did my dyno told me he thought it was running a little lean, he is seeing .83 to .84 lambda up top, is that lean for E85?

I have been running this for over a year and I looked at the data logs from a year ago and it shows the same thing, .83 to .84 up top but it's also running .80 to .83 all the way through the pull so is this a problem?

I am sending the logs to Justin at vmp for review but if it's always been like this and he has seen the old logs then maybe he intends for it to be that way.

I am not saying there is anything wrong with Justin's tune, I am concerned that I may be out of fuel or my pump is failing me.

Again this is NOT A thread saying Justin's tune isn't any good so let's NOT turn this into a tuner bashing thread!

Thanks guys.

 

[Bdubbs]

.82 is about 12.0 afr. And .85 is 12.5 afr I believe. So if that's the case, then yes your probably running a hair lean. Lucky your on ethanol or regular gasoline you may have had a problem already.

Edit: Also keep in mind, have you been running e70 on a e85 tune? Normally not a big deal, but if indeed you are running lean already and get some e85 in the tank, you'll be running even more lean.

 

[mackdog2008]

.82 is about 12.0 afr. And .85 is 12.5 afr I believe. So if that's the case, then yes your probably running a hair lean. Lucky your on ethanol or regular gasoline you may have had a problem already.

Edit: Also keep in mind, have you been running e70 on a e85 tune? Normally not a big deal, but if indeed you are running lean already and get some e85 in the tank, you'll be running even more lean.

It's a tune for E70 because we never have E85 here

 

[corepwn]

I tune for 0.77-0.78.

 

[Scott8583]

FYI E70 is crap for a boosted car... I'd check more stations if I were you, they don't all test the same.
Is it .83 just at the upper rpms? What's it at in the mid range?

 

[mackdog2008]

FYI E70 is crap for a boosted car... I'd check more stations if I were you, they don't all test the same.
Is it .83 just at the upper rpms? What's it at in the mid range?

Why do you say it's crap, seems to have been doing ok?

I have tested other places and also asked around and everyone says the best they have seen here is E73

I am almost sure it's .81 but I will get the logs tomorrow and let you know.

 

[mastwolf]

Iv made ALOT of power on E70...

E70 > ANY PUMP 93

On that note, You should be in the .77-.79 Range on the power adder. Dont even worry about Air Fuel Ratio because its gonna change with what fuel is in the car, just look at Lambda.

 

[bmoney50]

What is the commanded Lambda? If it is lean up top and the short term fuel trims are trying to add fuel I would say you are out of fuel pump.

 

[corepwn]

Really nothing wrong with E70 and making big power, the benefit is that it will require a small amount less fuel volume than E85 which will help people with shit fuel systems run it. Some people have it mixed up that the higher E number the better it is, it's just untrue. After E70 I'd say that there's diminishing returns, but you'll need a bigger fuel system to run it.

It really depends on the setup. Say a race car with no intercooler that needs the alcohol to keep things cool, E98 may be a benefit to there.

 

[Scott8583]

I was told by my tuner to stay away from E70. Recommended E84 or higher. Our local pumps test at 90% from May thru Oct.

 

[RAZRS EDGE]

Iv made ALOT of power on E70.......E70 > ANY PUMP 93

Agreed x1000

 

[4VFTW]

you are out of pump

 

[mystickb1996]

On e85 or in this case e70 why would 12.0 be lean? I tune my t trim alumiator which is 10.1cr at 11.8 on e85. Now I don't tune my coyote and I understand is a little higher cr but e85 burns cooler and resists detonation a lot better then 93.. Hence the reason you can get away safely with a little leaner tune. Corrections appreciated, just what Iv done for awhile.

 

[AKDMB]

Stoich of e85 is roughly 9.8:1 (pure gas has a stoich of 14.7:1) so at idle and part throttle you want to be at 9.8 and even richer at WOT. An NA Coyote will target .83 lambda at WOT which with e85, that would put your air fuel ratio at 8.077 this is with an NA car, you can imagine how much richer a boosted car would run, corpwn was saying .77 for a boosted car which is 7.546 with e85.

 

[Scott8583]

OP did you talk to Justin? What did he say?

 

[mackdog2008]

OP did you talk to Justin? What did he say?

Justin made a revision to the tune, he said it might help a tiny bit, I am going to data log it tonight but I am seeing on my gauge 0.79 all the way up until about 6500 then it moves to .80 and a one split second I saw .81

He said my pump is maxed out though, I will know more accurately when I datalog it tonight how it's doing now, I will be saving for a fuel system though since my system is at it's max.

 

[mackdog2008]

Update, I talked to Justin today after he reviewed the data logs and he said it looks good now with the tweak he made to the tune, also I am going to the strip tomorrow, it won't hook up because I am on street tires but at least I will get a run in.