Self tuning with e85

[blackrosenova40]

I have an automatic 1992 Eagle Talon and currently self tuning it with an evo 8 ecu. I have my fuel stable at 12.0:1 wot all the way through 7200 rpm. Previously was running 16deg advance at peak torque (5200 rpm) and 21deg at 7200 rpm. Thinking this may be too much, I reduced timing to 14deg at peak torque 5200 rpm and 18 at 7200 rpm. When i did this I found my boost raised 2 psi over normal (controlled by wastegate exhaust backpressure). It went from 31-32 psi to 34 psi. Fuel remained the same and logs show more airflow. Would this be a good sign that I may have past mbt or what do you guys think? Obviously with more retarded timing egts will rise and cause higher backpressure so I dont know if it would be a good sign I was past mbt.

 

[jed344]

Im no expert but 16deg at peak torque seems to high. 21 by end of pull seems normal enough on e85.

 

[blackrosenova40]

Well I raised the timing to ramp up to 20-21 degrees at 7000-7500 rpm and found my quarter mile times drop to around 11.4. Set the timing back down to ramp up to 18 and found my times improved back to 11.1. Im either going to keep going down with all wot timng and check improvement or get it professionally tuned.

 

[1qkfwd]

Your ET changes, what is you mph doing with those changes??

 

[blackrosenova40]

They dropped to 115-116 from 118-120

 

[1qkfwd]

All in the same day??

 

[jakeachy]

your et is not what you need to be concerned about when measuring power increase/decrease. your trap speed is the tell tale factor for that.

be more concerned with the car's doing, the trap, rather than your doing, the et.

 

[Mark4g63t]

Timing at peak torque on e85 should be between 5°-10° then ramp up to peak timing at the end of the pull, in your case the 7200 rpm mark.

 

[1qkfwd]

Timing at peak torque on e85 should be between 5°-10° then ramp up to peak timing at the end of the pull, in your case the 7200 rpm mark.

There is no set peak timing numbers when it comes to tuning.

 

[Mark4g63t]

peak timing meaning whatever he sets it to/ is able to get to, hence why I didn't list a number. For example right now my "peak timing" is 17°.

 

[1qkfwd]

peak timing meaning whatever he sets it to/ is able to get to, hence why I didn't list a number. For example right now my "peak timing" is 17°.

I put what you said all together in my head. But I really ment with what you said about the 5-10* at peak torque for E85.

 

[blackrosenova40]

Timing at peak torque on e85 should be between 5°-10° then ramp up to peak timing at the end of the pull, in your case the 7200 rpm mark.

Ive tried tiing that low, really made it weak.

 

[WES_393]

If you gained airflow and trap speed, then I'd say less timing was the right move. That's what street tuning is all about: Making adjustments to find that sweet spot. That's all professional tuners do, except they usually have the luxury of a dyno.

So nobody can tell you the exact numbers that should work best for your setup. But I can say from experience is that 21° peak timing is usually too much, and 10° is usually too low.

 

[jed344]

All set ups will be different aswell I am running 6deg timming at peak torque witch is 4400rpm on my car ramping up to 17 by redline.

 

[blackrosenova40]

What size engine, cams, turbo, and boost is this with?

All set ups will be different aswell I am running 6deg timming at peak torque witch is 4400rpm on my car ramping up to 17 by redline.

 

[1qkfwd]

What turbine housing are you running and what exhaust setup? Almost sounds to me like you were creating to much backpressure with the more timing. Are you monitoring turbine backpressure??

 

[blackrosenova40]

Raising timing should actually reduce exhaust backpressure as egt's would drop.

Extened tip 20g compressor wheel with evo 3 16 compressor cover, td06sl2 turbine wheel (9blade version), with an fp 8cm housing.

2.3 Liter 33psi of boost. Tuning with an evo 8 ecu.

I was bascially looking for a general way of tuning with ethanol which really seems to be go out and run it. I was especially curious because I can definatly feel the differance in the way the engine felt when dropping the timing down to 14-18 from 16-21. 16-21 degrees of advance made the engine feel "stretched" which is the only way I can describe it.

 

[My1GLaser]

Have you compared 70-90 mph acceleration times? Since that's easier to do on the street(interstate) and very repeatable, I use it quite a bit while tuning my car. I actually have an on-ramp where I do 3rd gear pulls every time I tune my car. It is a very consistent source of comparison for me, and right down the street

 

[blackrosenova40]

Ill have to try that although this is with an automatic, gearing is differant.

Have you compared 70-90 mph acceleration times? Since that's easier to do on the street(interstate) and very repeatable, I use it quite a bit while tuning my car. I actually have an on-ramp where I do 3rd gear pulls every time I tune my car. It is a very consistent source of comparison for me, and right down the street

 

[My1GLaser]

People also use 60-80 or 80-100 depending on the size turbo, but I can see how you would need a different range for the fact that you are auto.

What speed does 1st & 2nd gear top out at? (I'm curious also cause I am currently building an auto)

 

[jed344]

It's a 20g Frankenstein with 54mm inducer wheel clipped exhaust wheel 24psi stock cams 2.0 liter.