gasoline to e85 DIY tuning, and a few other tuning Q's.

[harvboi05]

first off, i just want to say i think its great to have a the new tuning section here on svtp. im considering converting to E85 in my vehicle and wanted to get a thread going for the DIY tuners here. im using PRP, and tuned my car to what i would consider acceptable standards on pump fuel.

my question is this, for swapping to ethanol, would i only change the stoich air/fuel ratio, and then continue with fine tuning the MAF transfer function? also, as far as ignition advance, its typically 4-8* of advance added from what i found. anyone have any experience with this? obviously id fine tune that on a dyno as well. just trying to get an idea of what to expect incase i actually follow thru with the swap, and just want to get some good info/dialog out there for people to search.

on a somewhat related note of closed-loop targets, im running E10 now, stoich is 14.1 for this fuel. so thats what im running for a target air/fuel ratio. i was considering leaning the target out to 15 for improved mpgs and etc. does anyone have any furious objections to doing so? ha.

I also need to rescale my load axis for my ignition values, for when i swap pulleys. what are people running for load values in their max allowed tables? i was going to scale mine the same as an 03/04 table upto 1.9 and then interpolate my current, dyno tuned ign values, but just wanted to throw it out there and see what people are up to. my top two load rows are 1.25 and then 1.6, which is certainly less than ideal; i need more resolution. especially because im already logging load values upto ~1.2.

thanks in advance guys.

 

[harvboi05]

anyone?

 

[x NOODLES x]

Good questions. Ill need this at some point too. Im sure Sleeper will pop in when he gets the time. :beer:

 

[04sleeper]

my question is this, for swapping to ethanol, would i only change the stoich air/fuel ratio, and then continue with fine tuning the MAF transfer function?

This is a good start that should get you close. You will need to redo all your STFT's first and just trend from there. Then fine tune.

You will also want to pull timing out while you are tuning and turn Adaptive Learning off like you normally would while dialing in the MAF curve.

also, as far as ignition advance, its typically 4-8* of advance added from what i found. anyone have any experience with this? obviously id fine tune that on a dyno as well.

With E85 you can tune at different loads/cells and keep adding timing until you reach MBT for each of those cells. Then maybe back off a degree or two.

Start out with the lower loads first and spend some time there. This is where most of the driving is done with the car and where a lot of driveability and fuel economy comes from. Anyone can tune for WOT in the top two rows.

on a somewhat related note of closed-loop targets, im running E10 now, stoich is 14.1 for this fuel. so thats what im running for a target air/fuel ratio. i was considering leaning the target out to 15 for improved mpgs and etc. does anyone have any furious objections to doing so? ha.

I have talked to a few people who tune like this and have actually acheived much better fuel economy with no side affects. I see nothing wrong with it personally.

I also need to rescale my load axis for my ignition values, for when i swap pulleys. what are people running for load values in their max allowed tables? i was going to scale mine the same as an 03/04 table upto 1.9 and then interpolate my current, dyno tuned ign values, but just wanted to throw it out there and see what people are up to. my top two load rows are 1.25 and then 1.6, which is certainly less than ideal; i need more resolution. especially because im already logging load values upto ~1.2.

That really depends on the car and the combo. You should scale your tune so it uses the whole table. 03-04 Cobras will run more load than an N/A car obviously.

Hope this helps.

Kevin