What is the general consensus on E85 AFR's during spool?

Right now I'm using AFR targets of:

AFR		RPM
13.0:1		1,500- 2,500
12.5:1		2,500-3,500
12.0:1		3,500-redline

I'm attempting to get within 2.5% either side of these targets. There is minimal or no knock.

Does this seem reasonable and safe? Am I leaving anything on the table? Any suggestions for different AFR's or breakpoints?

 

^^^^^^^^^^^^
TTT - I could really use some input from you E85 pros. What would be the ideal AFR targets during spool? Lean spool is off.

Thanks,
Jim

 

I could really use some advice on spool-up AFR tuning. I've recently turned off lean spool, so the entire map trace needed retuned. I had it pretty much dialed in at 12:1, but was advised to lean out the spool up area some more. I leaned it out, and now I'm getting knock that was not there previous.

Am I leaning it too much? Not enough?

 

On e85 you can shoot for 12.9 afr during spool up until peak load. Then taper it to 11.8-9ish for the rest of the pull. This will be conservative, but still yield good results.

To get spool to come on a little sooner try richening up the 90 load cells too. This will help with consistency from pull to pull.

I am not seeing an upgraded turbo in your signature, so I would shoot for 24psi.

 

I've never ran as lean as 12.9 for spool up. Leanest I run is 12.5's for spool up right now. So maybe it would spool up a little quicker if I ran 12.9?

 

I was at 12.0:1 during spool with no knock. I leaned it out to 12.5:1 and now I have knock. You are suggesting I lean it out even more, correct?

 

Sounds like your timing may be too aggressive if you can't lean it out without knock.

All I am saying is that e85 will handle much leaner AFR than pump. The basic, very basic, rule of thumb with pump 93 is mid 12s afr during spool and then mid 11s from there on out. Thus, e85 can handle it a bit leaner.

Are you 100% certain there isn't something mechanical that is the problem making the knock sensor go nuts?

 

I think it was simply a fluke. Did some more pulls last night, very minimal knock and AFRs are getting much closer to where I want them. I'm going to keep leaning out the spool-up area and see how it goes. Thanks Paul.

 

Just for the heck of it, get under the car and tighten up the knock sensor. If it is even the slightest bit loose it will read knock.

Also, if you have solid motor mounts, noisy injectors, or anything else loose that could rattle...it may set off the knock sensor.

You might consider raising the knock thresholds a tad.

 

Disclaimer:

This is only my opinion based on 2 years of running E85 on my Daily driver 500whp IX:

The "tip in part throttle" knock we all see (fuel independent) is either A) drive train noise, or B) Valve train noise.


My basis for this conclusion:

First timing: I have tried changing from where my timing is currently to as much as -8 degrees in tip in / spool up cells, no change at all in random knock (random 3- maybe extreme 10 counts), again random.

Second Fuel: In the process of tuning, then just recently retuning ( SD conversion ) I have run (during tip in / spool up) anywhere from 15.5 (don't ask) to 10.5 AFR and had no change in knock, although at target boost (28-31psi) under 11.0 will have some rich knock.


Again YMMV but this is what I have seen.

FP Red
fic 1050
QM Twin
Cams: (first set before the intake cam BROKE) GSC S2.
Current Cams: FP4R

Random tip in knock same at light / part throttle through out all the above mods.

I will post timing map once I transfer ecuflash to work pc, as I am fighting Decel stalling issue.

 

I agree that the majority of the time there is noise that has to be take into account, especially when big cams are installed. You can essentially "tune" the knock sensor to be less sensitive by using the Knock Multiplier tables.

For the sake of tip in knock you could always disable the knock sensor below...say 3000 rpm by raising the Knock Load value to max.

Your best bet is to log the knock voltage to verify if it is true knock or not. You will know by seeing huge spikes in knock voltage if it is real knock. Then simply raise the Knock Multiplier to compensate for the "noise"

 

12.8 for spool on e85. Sean ivey's advice.

 

exactly the process of what i did.

side note: appauldd what settings did you use to get ride of AC on car stalling?

 

What classifies as a huge spike? 1-2 volts for say 3-4 counts or higher? I've gotten 3 or 4 counts with a 1-2 volt knock voltage, but I've also had higher knock voltage with no counts at all.

 

The AC stall issues happens because of big cams in most cases....All I did was log what load my car wants to go into with the AC on, then added or subtracted timing. I also increased the AC on ISCV settings and the AC on idle RPM

The combination of these plus opening the BISS a tad will eliminate the AC stall.

As for the "huge spike" I noticed mine at like 1.8ish volts. Anything less appeared to be just noise. Trust me when I say....you will know when it is "real" as the knock voltage will go nutso.