E85 tuning notes

[fixem2]

is the first timing map your 92oct timing map?

[denver]

Originally Posted by mrfred

That's for the feedback on ignition timing at low loads. That's what I'm fiddling with again. I'm back to E85 for another three weeks, ... maybe longer if I can improve gas mileage enough to travel 240 miles on one tank during a road trip. So I'm fiddling again with E85 economy tuning... trying to get a feel for optimum ignition advance during offboost cruise conditions. I tried my current 92 Oct ign advance which has quite a bit more advance over stock and found that the car felt softer with E85 than with 92 Oct. There was virtually no knock with this map except at 70-80 load and 2500-3000 rpm. No matter what I do, the car seems spit out a knock sum of 2 in this range, so I don't worry about it. I pushed up ign advance by another ~2 deg in most all cells up to about 100 load. 15 minutes of driving wasn't enough to be able to tell whether its working. No additional knock though over the previous ign map. This is a situation where live tuning would really be helpful. Here are the before and after maps.

I had a complete stand a lone system and all custom built everything so thing were a bit differant, and again i havent had the experiance with the evo yet (Still gathering parts for the e85 converstion) but based on what I saw with my project, I bet you could advance the low load (no boost) area 4 to 5*over your 92oct tune with out an issue. Like I said in my previous post I went 8* to 10* on that motor, no problem at all....and Im still thinking about going farther with it to try and gain some off boost power. Its just a little 250cc so when you fall out of the boost its got nothing to keep it going..... :-) Granted its a little motorcycle engine and can take more timing than the 4G so you might be right on with the 2* you already add....

[dsmfan95]

Originally Posted by mdsevo06

Bring it back. Has anyone had Idle issues with E85 and the bigger Injectors? Any stalling when coming to a stop?

I'm on 1200's and decent sized cams with no stalling issues.

[mrfred]

Originally Posted by fixem2

is the first timing map your 92oct timing map?

Yep.

Originally Posted by denver

I had a complete stand a lone system and all custom built everything so thing were a bit differant, and again i havent had the experiance with the evo yet (Still gathering parts for the e85 converstion) but based on what I saw with my project, I bet you could advance the low load (no boost) area 4 to 5*over your 92oct tune with out an issue. Like I said in my previous post I went 8* to 10* on that motor, no problem at all....and Im still thinking about going farther with it to try and gain some off boost power. Its just a little 250cc so when you fall out of the boost its got nothing to keep it going..... :-) Granted its a little motorcycle engine and can take more timing than the 4G so you might be right on with the 2* you already add....

I'll try a few more deg.

[denver]

Originally Posted by mrfred

I'll try a few more deg.

Keep us posted!

[mrfred]

Originally Posted by denver

Keep us posted!

I've now added another 2 deg of timing in the 10-100 load cells across the driveable portion of the RPM range. I'm seeing timing values during low load cruise of 44-47 deg ign advance, and still no knock, so I've decided that E85 just will not detonate at loads of 100 or less. This leaves me with determining the best timing based on perceived power, and as with last time, I'm not sure if power is improved with 2 degrees more timing. This stuff must be burning really slowly.

Interesting thing is that my mileage is better than I thought it would be considering that E85 feels softer than pump gas and therefore takes a bit more throttle to get acceptable acceleration. I had been getting a consistent 20 mpg on pump gas, and since the stoich AFR for E85 66% of the stoich pump gas AFR, I was expecting somewhat less than 66% of the pump gas mileage because of the extra throttle needed for acceptable acceleration. That translates to no better than 13.5 mpg, but instead I'm getting 15+ mpg. Strange. Something is happening here that I don't understand yet.

Anyhow, I'm working on some possible ways to better nail down the effect of timing, but it may be a few weeks before I can get something going, so for now, I'm going to start pushing up the boost. I'm really feeling the need for power after staying off boost for over a month now! :-)

Here is my current timing map:

[razorlab]

mrfred,

Just as a point of data, I'm running approx 11* more than you at 7k at 240 load on E85.

However it is a 8 which tolerates a bit more timing at WOT than 9's.

I'll try to get that other data we spoke about next week.

[mrfred]

Originally Posted by razorlab

mrfred,

Just as a point of data, I'm running approx 11* more than you at 7k at 240 load on E85.

However it is a 8 which tolerates a bit more timing at WOT than 9's.

I'll try to get that other data we spoke about next week.

Yeah, I haven't messed much with timing in boost. All I've found so far is that I got about 10 more whp just by running E85 with the exact same timing and gasoline AFR and that leaning it out a bit gets me another 10 whp.

Thanks on the other item. :-)

[mrfred]

Originally Posted by mrfred

...

Interesting thing is that my mileage is better than I thought it would be considering that E85 feels softer than pump gas and therefore takes a bit more throttle to get acceptable acceleration. I had been getting a consistent 20 mpg on pump gas, and since the stoich AFR for E85 66% of the stoich pump gas AFR, I was expecting somewhat less than 66% of the pump gas mileage because of the extra throttle needed for acceptable acceleration. That translates to no better than 13.5 mpg, but instead I'm getting 15+ mpg. Strange. Something is happening here that I don't understand yet.

I figured out what's happening. Since this is my first tank of E85 after pump gas it probably has about 1 gal of gas mixed in which will raise the stoich after about 5-10% and increase gas mileage accordingly. Bummer. I thought E85 might actually produce better gas mileage despite the stoich values.

[denver]

Thats the same conclusion I had on my project. I was at 50* timing advance when the map was transitioning into boost range. I was still in the 25* to 35* range at full boost (10-15psi).

We got to the point on no load that we advance timing untill we lost accelleration. I had a complete dataAQ, and we graph accelleration during a 3rd gear pull, and kept advancing timing over areas till accelleration droped. We did have a dyno, but it worked well.

I would be supprised if the EVO took this much timming either.

I need to get my stuff together and get the evo converted!! Maybe this week........

[andrewzaragoza]

this is a pretty good thread for people who wants to self tune using e85. I have a question.. what afr are you guys running during closed loop operations? still 14.7?

[mrfred]

Originally Posted by andrewzaragoza

this is a pretty good thread for people who wants to self tune using e85. I have a question.. what afr are you guys running during closed loop operations? still 14.7?

I'm still running E85 at 14.7 gasoline afr, but will try to go leaner soon.

[andrewzaragoza]

Originally Posted by mrfred

I'm still running E85 at 14.7 gasoline afr, but will try to go leaner soon.

i see.. that would be good with the fuel economy if it is safe to run a closed loop afr of around 15.5. i wonder how lean could you run it without having any ill effects.

[mrfred]

Originally Posted by andrewzaragoza

i see.. that would be good with the fuel economy if it is safe to run a closed loop afr of around 15.5. i wonder how lean could you run it without having any ill effects.

I'm sure that 15.5:1 is not a problem. Could probably run leaner than that with E85.

[JohnBradley]

you can run between 16 and 17:1 cruise on E85 without misfire and run 40* of timing at cruise.

Timing maps will generally look the same at peak boost as a pumpgas map (with more boost to makeup for it), run lower timing numbers to about 5500, ramp harder to 6k and then about 10 more degrees to 8k on a stock turbo...samples would look something like this:



This was for an ETS 57 trim on E85 with stock MAF, Stock cams, 3.5" FMIC, pipes, and 28psi. It made 440whp and like 351 torque on a dynojet that always seems to read low torque (maybe rpm sync?)