what needs to be changed tuning wise for e85?

[ctgreddy]

I've got almost everything I need for my fuel system, so looks like e85 will be a go for me come spring. The things I need to figure out are what all needs to be changed tuning wise? I know the obvious, changing the stoich of the fuel, changing wot timing, etc. But what other things are there? Like does an e85 car like more timing throughout the entire table, what lambda value should I be targeting for wot? And anything else a beginner like me needs to know.

The car in question is the one in my sig, 03 cobra with sct pro racer package, 2.8 kb mammoth and will be upping the boost to ~22 lbs as I dont want to push the stock head studs too far. Fuel system will consist of dual aem 320e's, stock hat modified for better pump wiring, dual fpdm's, 8an feed, stock rails and frpp 80's. Just aiming for anything over 700whp.

 

[lowranger96]

for e85 tuning:

first make sure fueling is all in terms of lambda,
there should be a fuel afr stoich scalar that is currently set to 14.08-14.7 something like that, you'll want to change this to the stoich ratio for e85 which is 9.7.
then you'll want to increase your cranking fuel pw by 25% (multiply cells for pw by 1.25)
i would do some datalogging to make sure that everything is working well (your wideband will still read out gasoline numbers so if it was at 11.5 wot afr then it will still read 11.5 now.. this is because the wideband reads the lambda and converts it into gasoline numbers.. so unless you have a wideband that you can change to e85 numbers then it'll read the same as what gasoline read. keeping in it terms of gasoline afr often makes it easier imo)
after that you can add a few degrees of timing to enjoy all the perks of that added octane

ps: watch your injector duty cycle with those 80s at 700whp on e85, you might run out of injector

 

[ctgreddy]

for e85 tuning:

first make sure fueling is all in terms of lambda,
there should be a fuel afr stoich scalar that is currently set to 14.08-14.7 something like that, you'll want to change this to the stoich ratio for e85 which is 9.7.
then you'll want to increase your cranking fuel pw by 25% (multiply cells for pw by 1.25)
i would do some datalogging to make sure that everything is working well (your wideband will still read out gasoline numbers so if it was at 11.5 wot afr then it will still read 11.5 now.. this is because the wideband reads the lambda and converts it into gasoline numbers.. so unless you have a wideband that you can change to e85 numbers then it'll read the same as what gasoline read. keeping in it terms of gasoline afr often makes it easier imo)
after that you can add a few degrees of timing to enjoy all the perks of that added octane

ps: watch your injector duty cycle with those 80s at 700whp on e85, you might run out of injector

I have an aem failsafe which I'll be setting to lambda so I dont get concerned with tuning e85 per gasoline afr readings.

I've heard mixed reviews on the 80's. some say they made 750+ with 80's on e85 and others say it wont be enough. Injectors are the thing I don't have yet so I can switch that up if need be. I'd love to get some ID's but dont want to pay those ridiculous pricing. Was thinking more about going with some Deatschwerks 88's.

Whatever injector I go with will have to be decent enough that I can make a gasoline tune as well for the times I take the car on vacations when e85 wont be available. I dont care if it's a perfect tune with perfect driveability just as long as it'll run/drive decent on gasoline.

 

[Bdubbs]

for e85 tuning:

first make sure fueling is all in terms of lambda,
there should be a fuel afr stoich scalar that is currently set to 14.08-14.7 something like that, you'll want to change this to the stoich ratio for e85 which is 9.7.
then you'll want to increase your cranking fuel pw by 25% (multiply cells for pw by 1.25)
i would do some datalogging to make sure that everything is working well (your wideband will still read out gasoline numbers so if it was at 11.5 wot afr then it will still read 11.5 now.. this is because the wideband reads the lambda and converts it into gasoline numbers.. so unless you have a wideband that you can change to e85 numbers then it'll read the same as what gasoline read. keeping in it terms of gasoline afr often makes it easier imo)
after that you can add a few degrees of timing to enjoy all the perks of that added octane

ps: watch your injector duty cycle with those 80s at 700whp on e85, you might run out of injector

So do people that run e85 stick with gasoline a/f on there wideband? That part always seems confusing.

 

[cj428mach]

I'm targeting .781 lambda but I guess its however lean you want to push it.

You might want to bump up the fuel pressure, I'm running my ID1000's at 50 psi to give them plenty of room. I know 04sleeper said he did the same with his 80's.

 

[ctgreddy]

So do people that run e85 stick with gasoline a/f on there wideband? That part always seems confusing.

There's a lot of people that do that. Nothing wrong with it but I just like the idea of using lambda.

cj, as far as psi for injectors that'll all come down to when I get it going and what needs to be done. But if need be I'll turn up the pressure a little.

 

[lowranger96]

Yeah it doesn't matter how your wideband is spitting out the numbers as long as you know what setting its on.

You can get the same Bosch injectors that injector dynamic sells for cheaper but they won't be flow matched like the Id's are. That's the benefit of getting their set. The Bosch ones are nice because they can stay in their linear range at idle unlike some of the Dekas and cheaper injectors. When they become nonlinear at lower pulse widths that is where your driveability issues come into play. I'm idling a 2.3 turbo motor with id750s without any driveability or idle issues.