AFR for E85 - recommended Spark plug gap?

[Gizmovr4]

I'm looking to run the car on E85 this Friday at Island Raceway- What AFR should I be targeting with the AEM wideband set to regular gas? 12:1 ? 12.5:1 ? for E85 whats the recommended spark plug gap if I run 30PSI? Any recommendations from those runing E85?

 

[Muskrat]

I'm assuming you have enough injector to run E85?

I'm not an expert, but here's some info:
Stochiometric afr for E85 is 9.7:1 vs. 14.7:1 for regular gas.
I don't know if the wideband needs to be recalibrated for E85 or not.

 

[thecman02]

If you have the wideband set for gas 12:1 or even 12.5:1 should be okay. I'd run the largest gap you can get away with, but I wouldn't think .028 would be a bad place to start. If you get misfires close em up some. If you still have misfires with gaps much smaller then .024-.02 then I'd say you need to get your ignition system up to par.

 

[Nartanian]

11.8:1 wouldn't be bad either.

 

[Street Surgeon]

30psi? Use some BR8ES or BR9ES plugs and gap for .25 to .22 (the larger you can get away with the better)

 

[Nartanian]

Missed that part. /ubbthreads/images/graemlins/uhh.gif

 

[Brianawd]

No need to use a cooler plug. E85 burns cooler so you can get away with a hotter plug. I find that 6s-7s work best. I run 7s in the hot summer and 6s in the spring and fall when the temps start to drop. I find if I run 7s I in the cold I have to drop my gap down to 18-22. When running the 6s I can keep my gap around 27-28.

As for aft 11.5:1 to 12.0:1 with a max timming of 21degs.

 

[NateCrisman]

Quoting Brianawd:
No need to use a cooler plug. E85 burns cooler so you can get away with a hotter plug. I find that 6s-7s work best. I run 7s in the hot summer and 6s in the spring and fall when the temps start to drop. I find if I run 7s I in the cold I have to drop my gap down to 18-22. When running the 6s I can keep my gap around 27-28.

As for aft 11.5:1 to 12.0:1 with a max timming of 21degs.



Ditto. From all I have read, and I said this on the phone today, I think E85 will make good power at a wider AFR than gasoline, so it's a bit more tolerant to messy tuning.

So long as you've got a datalogger with you, Ill help ya out with the AFC tuning. /ubbthreads/images/graemlins/applause.gif

 

We run 8's and AFR of 11.8-12.0

 

[Gizmovr4]

Nate,

You know i'll be taking you up on that /ubbthreads/images/graemlins/grin.gif

Are the plugs BPR7's or just BR7's?

 

[3rdstrikedsm]

As stated above 12.0 is good but usally makes no more power over 12.2-12.3 so keep it at a safe 12.0.

 

[NateCrisman]

Quoting gizmovr4:
Nate,

You know i'll be taking you up on that /ubbthreads/images/graemlins/grin.gif

Are the plugs BPR7's or just BR7's?



BPR7ES for projected tip plug is what you want. You don't want to run BR7ES or BR8ES unless your spraying ALOT of nitrous. (I still use BPR7ES plugs gapped to .028 when spraying under 100shot)

honestly, stock ignition is so damn good with these cars!

 

[DougPorcaro]

I was under the impression for high boost applications it is better to not run the projected insulator types (BPR) because it places the spark more in the flow path of incoming air. I have read many people solving their spark blow out issues by switching to BRs, over equally gaped BPRs.

 

[OMFGeofffff]

This is a little off topic sorry but its a quick question. Is it normal for the wideband to fluctuate when at idle and cruising?

 

I just made 678hp on E85.

Plugs: BR8ES @ .020
AFR: 11.8-12.0

I tried afrs from 12.0 all the way to 13.0, and my seems to really like 12.0 and less. Also with E85, it is very pickey about everything. So you are going to need to play with it to make it happy. You will need to try differen AFRs and different timing until you find what your car likes. The info you are going to get from most people will more than likley not help you at all. I went back an fourth trying sh*t that people posted up.

So get the afr's about the high 11's and work from there.