Ignition Timing for e85

[wishihadatalon]

This question has nothing to do with wide open throttle tuning. I am more interested in seeing what you guys have done in vacuum and cruising with your ignition timing. Are you increasing the amount to help it burn more and use it to its full potential? Are you leaving it the same as pump gas? This question is an attempt to get better fuel economy with e-85 any way that I can. Any help would be appreciated.

 

[turboglenn]

I've added about 5-7* everywhere through out cruising... At 0 vacuum/0 boost i'm running about 30* of timing from 3500 and up and anywhere lower i have about 27, 24 20 slowly lowering as it goes towards idle RPM's. But basically all i'm saying is yes i have used the timing to take full advantage of teh E85 fuel

 

[wishihadatalon]

I've added about 5-7* everywhere through out cruising... At 0 vacuum/0 boost i'm running about 30* of timing from 3500 and up and anywhere lower i have about 27, 24 20 slowly lowering as it goes towards idle RPM's. But basically all i'm saying is yes i have used the timing to take full advantage of teh E85 fuel

I am pretty much running a 1g timing map in my megasquirt right now. Cruising on the highway I am seeing 34 degrees of timing and I am running 14.7 afrs pretty steady. I am thinking about leaning it out at low load but I am wondering if I am going to have to raise the timing to really take advantage of this.

 

[Black_Bullet]

So have any of you noted an increase in mpg from increasing timing ( for example like what TurboGlenn did in above post ) I take it that increasing the timing gets you better mpg due to useing the energy more efficiently?

 

[turbotalon1g]

Same question here, good question. does this work.

 

[wishihadatalon]

So have any of you noted an increase in mpg from increasing timing ( for example like what TurboGlenn did in above post ) I take it that increasing the timing gets you better mph due to useing the energy more efficiently?

Exactly what I was wondering. There was another guy on here with a DSM who was getting 50mpg and he mentioned it a little bit. It makes sense, but I want to know exactly what I should be looking for. I don't have an egt gauge which might actually be the biggest help here.

 

[turboglenn]

I gained more mileage by leaning out the cruise adn light accel areas of the map then i did by adding timing. In town the best i can get on lean AFR's and high timing is about 14MPG... If i take away the leaness and make it rich enough to acclerate decently i go down to about 13mpg. I would say timing gave me about 1mpg total by advancing it beyond what pump gas would like because i was only getting about 11 with the richer AFR's and timing was my next step to try and gain some back. I went from about 24* timing at 0 boost/0 vac to roughly 30 in most of the same areas and that's what brought me from 11 to 12 mpg on the rich tune.

The reason i did away with the lean tune that yielded 14mpg was that when i floored it in first, the turbo would not spool and it wouldn't make any power until after 5k rpm because the leaness perpetuated a massive lean bog anytime you stepped into first gear trying to get out in traffic fast is when it really hurt me.

Anyway, i've been drinking a little so my typing is harder than usuall, so hopefully that helps, if you need more info let me know and i'll reply tomorrow

 

[snooopy365]

does anybody have an idea how lean it is most effectiv? with gasoline its 16.2:1 but whats about E85?? I want to tune for lambda 1.2 while cruising, but maybe even leaner will be better?

 

[Black_Bullet]

So more timing and leaner AFRs and you likely get better mpg..
With timing I imagen the key is getting as close to MBT as possible were the engine is using the available airflow as efficiently as possible ....

 

[wishihadatalon]

So more timing and leaner AFRs and you likely get better mpg..
With timing I imagen the key is getting as close to MBT as possible were the engine is using the available airflow as efficiently as possible ....

Correct, it is too bad that neither of us can afford a dyno I will be leaning out the afrs on the way to the shootout tomorrow and I am going to play with timing as well. I will do what I can to get better MPG.

 

[JayRolla]

Just to add, ive played with different afr's while cruising and I really never see a noticeable difference in gas mileage. My .5 of a mile better average at most.

 

[wishihadatalon]

Update***
We took the car to the dsm shootout this weekend and I let her drive while I ran the laptop. I went from a steady 14.7afr at cruise to a 16.2afr. I upped the timing 2 degrees in all vacuum cells and tried to see what kind of mileage I could get out of it. Best results before these changes was 22mpg. This was down from the 33mpg that I got on gas. After the changes I am back up to 28mpg on the highway WTF . This meets and exceeds my goal to get it back to 26mpg so for now I am very very happy with the results I have gained.