bchappy

Well I was thinking in the 11.5 range...
however I have been running 12 throughout and anytime I try to add fuel I get sporadic counts of knock.
Timing is pretty conservative I think 4@ peak and tapering to 18?
What do ya guys think?

Jim in Tucson

iTrader: (3)

I think 12:1 AFR should be good for street and/or track.

I don't track my car, so take my advice very lightly.

I suggest staying with the same AFR on street and track. And 12:1 sounds good.
For the track, I'd run less boost. Not because of E85 or anything related, but simply because you are staying in boost for much longer periods of time and at an increased frequency. I'm assuming stock, or stock frame turbo.

If your street tune is right at MBT, and if you wanted to be even more cautious, you could have a special track timing map with some additional margin.

Will most tracks let you have your laptop along? If so, simple data log just like you would on the street. Let your car tell you what it wants, or what it needs to give up.

lan_evo_mr9

iTrader: (10)

I have mine set to 11.7-11.9 for track use and that has worked pretty well. I wouldn't go any leaner than that for a track day or autocross. I personally haven't seen significant power gains above those figures anyway....

My timing values are pretty similar, although I'm running a bit more up top and a little lower at peak load...not much though, a degree or two lower and 2-3 degrees higher up top.

Hope that helps.

bchappy

Ya with the 8 you can run a bit more timing. I just go a little richer and the car gets little 1-2 counts, which I dont like, I would rather have no knock like I have at 12.0. Ill have to play around a little on tomorrow and see whats going on.

lan_evo_mr9

iTrader: (10)

didn't notice you're running an 8...timing is cool. Maybe lean it out a tad. Other than that, it's perfect. Good job man.

casper980

iTrader: (6)

Personally, I don't trust E85 for track use. Maybe its because I have already blown an engine on the track, maybe its because I was told not to use E85 on the track. E85 is not a consistent fuel from pump to pump or season to season. I would like to see AMS chime in on this and give us their opinion.

casper980

iTrader: (6)

I also thought that E85 was supposed to have a much richer AFR then petrol. Here is a table I took from wikipedia.

Table

The following table shows the range of air fuel ratios typically used for burning gasoline, E85, and pure ethanol (E100) under an assortment of assumed operating conditions:
Fuel AFRst FARst Equivalence Lambda
Ratio
Gasoline stoichiometric 14.7 0.068 1 1
Gasoline max power rich 12.5 0.08 1.176 0.8503
Gasoline max power lean 13.23 0.0755 1.111 0.900
E10 stoichiometric 14.0 - 14.1 ? ?
E85 stoichiometric 9.765 0.10235 1 1
E85 max power rich 6.975 0.1434 1.40 0.7143
E85 max power lean 8.4687 0.118 1.153 0.8673
E100 stoichiometric 9.0078 0.111 1 1
E100 max power rich 6.429 0.155 1.4 0.714
E100 max power lean 7.8 0.128 1.15 0.870

Looking at this table it shows E85 Max lean mixture to be 8.4687, if your running it at 12:1 then you are WAAYYY lean.

Maybe I am missing something. Chris at AMS does my tuning for track use on pump 93 and my AFR goes to around 11.1 in boost

tscompusa2

iTrader: (22)

on a gasoline wideband it likes 11.8 usually. my personal vehicle i can do 11.2 to 12.2 it wont knock. More timing is not always better with e85, especially at peak torque/load area. if your cars not knocking lean and knocking rich, id suspect its slightly over mbt. it wont show knock if you run it to lean even if its past mbt.


also every car likes different a/f so test with your vehicle. if you do a pull at 11.5 and then 11.8 and you see gain, then keep it at 11.8. now if you go from 11.8 to 12.0 and see enough gain to make it worth running then keep it there. if you go from 12 to 12.2 and you still see a significant gain, then maybe stick with 12.2, but a road course vehicle id do 11.8 for max, since egt's will be important.

1outlaw

Could it be that in reality by running leaner than most boosted applications (.76-.78 lamda) you are in effect slowing down the burn thus having a somewhat effect as to pulling back timing? E85 at peak load and stoich burns pretty fast whereas rich and lean less so. Could it also be the plug types you guys are having to run triggering the beginnings of pre-ignition?

Not meaning to threadjack here but I posed this question over where Hotrod and Shortbox could see it- note their comments on page 2 of this thread near the bottom;

http://e85forum.com/about1146-0-asc-...be36c25aa6d6fd

Just throwing this in for thought- I think you guys are dead on with what you are doing but wanted another viewpoint from guys who have also been doing boosted E85 for several years in other engine types.

1outlaw

Casper- for track use you can be very consistent if you buy E98 in a drum (there is a decent source in Mich) and mix your own with your choice of pump or unleaded race gas (depending on your octane needs).

casper980

iTrader: (6)

Now that's good info...might be something I look into in the future for a cheaper substitute to race gas. Thank you. So you agree with me that E85 from the pump is not consistent enough for track use? I just want OP to have all the info possible. I know how it feels to call a tow truck at the track and need to replace an engine.

1outlaw

Casper- there are some tunes, boosts, and CR's that will be more safe on hand mixed E85. However- what a lot of track race guys do is drum up from a retail pump what they need for the season and then tune for that. If the engine is really "on the edge" then hand mixed E85 or wait until summer blend is at the pump, then drum enough to carry out a year will work (keep barrels well sealed and in proper place). A few who are NA 15 or 16:1 or very high boost will even go to Rockettbrand's E85 (109 motor/116 research/112 rm/2) but this is pretty costly if you do not need it.

Let me know if you do decide to try the E98/gas mix route Casper- I would dig around to find the thread on another forum where guys were doing this in Michigan and had a local source of E98 direct from an ethanol plant.

goofygrin

iTrader: (5)

I have an ECA and I log what the pumps do around here.

They are fairly consistent. We shifted from our winter blend (E78/9) to our summer blend (E83) a few weeks ago. One station was slow to switch though.

We have one station that is true E85 all the time.

ETA: I say 11.8-12.0 (which is what I run). I'd rather run 12.0 with no knock than 11.8 with 1-2c of consistent knock.

casper980

iTrader: (6)

Outlaw thanks for the info, I will, E85 always looked promising to me, but I never trusted it. What your saying makes sense to me, so I might actually consider it. Does the Rockettbrand cost more than 110 ($6.00+)?

OP, take note of what these guys say/do, we don't want to blow up anymore 4G63's

TheBoz

iTrader: (9)

For the past few weeks I have been playing with AFR's, Timing, and Plug gap to fully understand E85. The thing that I have found is that everyone has there own idea of how to tune it.

I have tuned from 12.0-13.0. Now in my experence it seems that the car like a slightly leaner mix. When my car dips into the 11's I will start to get knock, it does not matter what the timing is.

Me personally I am tuning my car in the 12.0-12.3afr range.

So best bet for you is you are going to have to play with it. Also find out what E% you have. That way you have your baseline for a specific E% fuel.