Thread: Testing E85. Do you?

Changing cylinder gain / offset does the same thing.

It is much easier to do it that way^^ than changing stoich.

There is a ton of stuff that needs changed in addition to the stoich table if you are choosing that route.

Originally Posted by GTPpower

It is much easier to do it that way^^ than changing stoich.

There is a ton of stuff that needs changed in addition to the stoich table if you are choosing that route.

If going this route, will the wideband still read the same as it would for 93 octane?

Originally Posted by GTPpower

It is much easier to do it that way^^ than changing stoich.

There is a ton of stuff that needs changed in addition to the stoich table if you are choosing that route.

Not really and it's already been proven

This may be taking the thread off track a bit, but I think it might be worth it, so her goes;

Stoich vs. Cylinder gain....

Iv'e seen a couple times here and there that this method is better than that method, or that way is easier than this way.... As someone who is just beginning tuning, and not really married to one method or another, what I would like to see is factual arguments on why one way is better than the other. Also, where one method falls short compared to the other.

Why do you believe you method is the "better" way?

Here are my thoughts. http://www.grandprixforums.net/threa...ur-car-for-e85

To put it simply the cylinder gain method only requires changing one table in the entire tune. If you need to adjust for summer and winter blends it still only requires tweaking the one table. Calling it a table is a stretch even. Its 6 slots that you change from 1 (100%) to 1.25 (125%). Simple and effective.

And I have laid out my explanation as well. And you have the link for 97autovettes writeup. As indicated both methods work. As for my reasoning, well your changing stoich of the fuel so why fudge another table fnot something that never needed adjusting?

Originally Posted by 91parkave

Not really and it's already been proven

I ran e85 for a bit using the stoich option to change it. You need tiny tuner to make all the changes required. Changing cylinder gain, or IFR, you only need to change that one table. Way easier to leave stoich alone.

Originally Posted by timboku

If going this route, will the wideband still read the same as it would for 93 octane?

You can either run the wideband like on 93 and tune for 11.5 or whatever at WOT, or switch it to e85 and run it at 7.8 or whatever it should be.

Originally Posted by GTPpower

I ran e85 for a bit using the stoich option to change it. You need tiny tuner to make all the changes required. Changing cylinder gain, or IFR, you only need to change that one table.

cause it was really hard to make some more changes

Originally Posted by 91parkave

cause it was really hard to make some more changes

It's way easier to just change one, instead of accidentally missing one. If you only have HPT, you don't have an option.

So what happen when you swapped stoich values in the master stoich table what happened? Did your afr go back to 14.7 anyway?

Originally Posted by 91parkave

So what happen when you swapped stoich values in the master stoich table what happened? Did your afr go back to 14.7 anyway?

On a wideband calibrated for gas, yes that's what it would have read in closed loop.

Originally Posted by 91parkave

So what happen when you swapped stoich values in the master stoich table what happened? Did your afr go back to 14.7 anyway?

I wish there was a master one like the LS guys have

I think my tune is pretty happy. Running 100% original GM maf table for the 4" truck maf sensor from zzp and 100% correct injector offsets and flow rate. WOT fueling is commanding a static 10.8 commanded afr. Fuel trims are within 5%. Only hacked table is the cylinder gain set to 1.2. Here are the results. Keep in mind this is running winter blend E85 (So actually e70) and a gas calibrated wideband.

IIRC, you said you were running 60lb injectors?

So your IFR table is "60" across the board? No change per manifold vacuum?

Set to 63 across the board. The flow-bench balanced them all out at 63 so thats what I run. Only other fuel system stuff is a AEM 320lph E85 pump. (Im a big fan of using math and logic to tune. Although I have a great talent for educated guessing when I need to. I once modded an entire maf table with only 5 minutes of driving and two wot pulls sent to me in a data log to tune off of. The entire table was within 6% fuel trims when the guy flashed it :P)

Okay. I'm running the same pump. No rewire (yet). With 42.5lb injectors.

If you're running a return style system than regardless fu El should be flat across the ifr table. Return less style are gls generally a upward slope.as stated above