AFR and E85....What are you aiming for?

[blackmonte]

14.7 here at idle , and 15.8 lean cruise

 

[Rafs-T-Type]

14.7 here at idle , and 15.8 lean cruise

high 13's-low 14's at idle - high 17's lean cruise-----sometimes even 18's and low 19's!

 

[forcefed86]

I managed to blow a head gasket tuning around 11.5 and 18* timing. I think every engine will be different as far as fueling goes. My eagle talon is also e85 and I made the most power at 12.5 AFR's.

If you can get a dashboard dyno or go to a drag strip this is what works for me.

First get your AFR's in the low 10's and your timing conservative (14-16*). Then set your desired boost. Next, watch your MPH as you lean out the AFR's. Once you stop going faster lock in the AFR's and bump timing up slowly. Again, your MPH will tell you when to stop. All this is assuming no knock of course.

Just a word to the wise I got no indication of knock before blowing my HG. With alcohol I'm told it is easy to skip detonation and go straight to pre-ignition. So be careful. Reading the plugs as you dial in timing is recommended.

FWIW (using gas scale WB02) I'm around 13.5 idle and 14.5-16.0 cruise. 10.2 WOT haven't blown another gasket, but I'm still tuning WOT.

7.1 here with a energy constant of .68 at max load(30psi)

Is that actual e85 scale? Your not talking STD gas scale are you?

 

[huckleberry]

scaling

I;m sorry, but you guys are using gas scaling,because if you use these numbers in E85 scaling, you won;t last too long !! Actual numbers< air verses fuel-e85>would be in the range of WOT would be more like 7 parts air, 1 part fuel <e85>.. Be careful !!

 

[forcefed86]

I;m sorry, but you guys are using gas scaling,because if you use these numbers in E85 scaling, you won;t last too long !! Actual numbers< air verses fuel-e85>would be in the range of WOT would be more like 7 parts air, 1 part fuel <e85>.. Be careful !!

7.2 e85 afr converted to gasoline afr is 10.8 afr.

The safe start point is 10.5-11.0 gas scale on most setups with 85% eth. content. Because ethanol content varies I would always suggest tuning to max rich power.

 

[Rafs-T-Type]

TTT

 

[northerngn]

mid to upper 7's using E-85 scale with xfi

 

[Rafs-T-Type]

mid to upper 7's using E-85 scale with xfi

What IDC are you at on those 83's?

 

[northerngn]

What IDC are you at on those 83's?

Sadly,they hit 100% around 21lbs of boost gotta step up the injector program now,but this is with a built motor and pretty big turbo...see sig
-Dan

 

[CGASTON]

scaling

I;m sorry, but you guys are using gas scaling,because if you use these numbers in E85 scaling, you won;t last too long !! Actual numbers< air verses fuel-e85>would be in the range of WOT would be more like 7 parts air, 1 part fuel <e85>.. Be careful !!

The scaling for E85 at 9 A/F, which is the 14.7 A/F for gas. You run at a gas scale and just convert it.

 

[northerngn]

The scaling for E85 at 9 A/F, which is the 14.7 A/F for gas. You run at a gas scale and just convert it.

Actually its 10/1
this is copied and pasted right off of my XFI help glossary

 

[turboxan]

thinking on converting to E85. stock internals, TE44, front mount IC, 20psi, A l000 pump 72#inj, fast xfi, it is in my gmc p/u. so A/F should be 7.1-8.1 to be safe?

and will the xfi O2 read that low?

 

[Rafs-T-Type]

thinking on converting to E85. stock internals, TE44, front mount IC, 20psi, A l000 pump 72#inj, fast xfi, it is in my gmc p/u. so A/F should be 7.1-8.1 to be safe?View attachment 170516 and will the xfi O2 read that low?

I only know it on the gas scale. From my reading 11.4 is safe max rich hp. In the 10's like normal is really rich on E-85 and performance takes a toll. People run down to 13 with no problems, but most observe max rich get them the best numbers. This is all from many hours of reading and not first hand experience. And of course every car is different.

 

[Boost231]

xfi will read that low. 7.1-8.1? how much boost are we talking about for the a/f ratio?

309kpa 7.1 would be sfe

175kpa 8.1 would be safe

 

[BEATAV8]

Was running 10.8, now running 10.5. Moving to 10.3 or 10.2 next......

6776 turbo, GN1 heads and 120lb injectors. Injectors in the mid 80's just below 6000RPM.

 

[TurboBuRick]

Was running 10.8, now running 10.5. Moving to 10.3 or 10.2 next......

6776 turbo, GN1 heads and 120lb injectors. Injectors in the mid 80's just below 6000RPM.

How much boost?

 

[BEATAV8]

How much boost?

25-26 and looking to move up to 28.
Right now it's tickling the knock sensor 0.7 deg to 1.1deg but the plugs show no indications of any speckles on the porcelains.

 

[Rafs-T-Type]

Was running 10.8, now running 10.5. Moving to 10.3 or 10.2 next......

6776 turbo, GN1 heads and 120lb injectors. Injectors in the mid 80's just below 6000RPM.

The more I read the more it seems like 10.x is too rich and people are loosing power there. I wonder if that knock you are getting is false.

 

[BEATAV8]

The more I read the more it seems like 10.x is too rich and people are loosing power there. I wonder if that knock you are getting is false.

I'm pretty sure it is false, it never goes away. With much lower boost and much much lower timing it still shows the same KR. I am still looking for the source and have a few items of suspect nature....

In the mean time I am keeping it at 25 psi, 18 timing and watching the plugs.

 

[jasjamz]

I'm pretty sure it is false, it never goes away. With much lower boost and much much lower timing it still shows the same KR. I am still looking for the source and have a few items of suspect nature....

In the mean time I am keeping it at 25 psi, 18 timing and watching the plugs.

Take it to the track and see how it runs there as a baseline. Knock sensor...was I suppose to plug that back in?