Black Bear Tune

[blueflamed03]

but are those Flex Fuel vehicles?

 

[Eagle]

The deal with e85 is this.

it is
a: corrosive to seals and some metals
b: has les energy per gallon,
c: and stoich is a differnt ratio, so you need either longer pulses or larger injectors to achieve the same combustion ratio


D: the higher cotane means it burns more slowly and coolly, so you can run leaner OVERALL mix or more timing with e85 or higher compression (or all the above) than you cna with gas.
e: IIRc ethanol actually ignites about as easily as petrol and atomizes about as easily so you don't need some monster spark system


What would be a piston melting tune on 93 octane gasoline, and a ragged edge tune on 100 octane unleaded, is very safe on e85. Thus unless you have a flex fuel vehicle, if you tune for e85 and then have to fill up with gas, you are going to run like poo... Way way fat, and probably knock from excessive timing too.


IIRC e85 was about the 42% less energy, stioch was around 9.7:1

You would think you needed to throw 42% more fuel to make up for it, but you don't. What folks did was run ~25% more injector so you get a leaner final mix under open loop, and let the ecu find stoich with it's adaptation. Then bump the timing up 3-5 degrees.


At least that is how you do it on OBDI vehicles that my friends have converted in other places to run on it.


Problem is again that when you are NOT using e85 *** it isn't flex fuel, the timing and fueling are way off, and you get poor power and economy. you need to reflash it back.

 

[Grocery Getter]

The deal with e85 is this.

it is
a: corrosive to seals and some metals
b: has les energy per gallon,
c: and stoich is a differnt ratio, so you need either longer pulses or larger injectors to achieve the same combustion ratio


D: the higher cotane means it burns more slowly and coolly, so you can run leaner OVERALL mix or more timing with e85 or higher compression (or all the above) than you cna with gas.
e: IIRc ethanol actually ignites about as easily as petrol and atomizes about as easily so you don't need some monster spark system


What would be a piston melting tune on 93 octane gasoline, and a ragged edge tune on 100 octane unleaded, is very safe on e85. Thus unless you have a flex fuel vehicle, if you tune for e85 and then have to fill up with gas, you are going to run like poo... Way way fat, and probably knock from excessive timing too.


IIRC e85 was about the 42% less energy, stioch was around 9.7:1

You would think you needed to throw 42% more fuel to make up for it, but you don't. What folks did was run ~25% more injector so you get a leaner final mix under open loop, and let the ecu find stoich with it's adaptation. Then bump the timing up 3-5 degrees.


At least that is how you do it on OBDI vehicles that my friends have converted in other places to run on it.


Problem is again that when you are NOT using e85 *** it isn't flex fuel, the timing and fueling are way off, and you get poor power and economy. you need to reflash it back.

Good info! This is in reference to non flex fuel vehicles? If it is flex fuel all the corrosion issues are not applicable and it is set up to hand both, am I right?

---------- Post added at 11:54 AM ---------- Previous post was at 11:53 AM ----------

but are those Flex Fuel vehicles?

Yes, Flex fuel for sure. I'd never try it if mine wasn't.

 

[Eagle]

Good info! This is in reference to non flex fuel vehicles? If it is flex fuel all the corrosion issues are not applicable and it is set up to hand both, am I right?

Yes on flex fuels, from my limited reading about them, are set up with some mean of reading the alky content of the fuel, and thus adjust themselves back and forth.


I really should go see look at the vin to see if the tahoe is a flex fuel truck. It was from Cali, but I seriously doubt it is.

 

[gtbigup01]

Does anyone have dyno graphs to back up these claims of power gains or is it just butt dyno? Do you guys ever take ur trucks to the track? Excuse my questions but I'm coming from the car world (****) no not Honda civics, but Infiniti G35 and Nissan maxima, my point is when I see talk of power gains I like to see more than words, dyno graphs or track slips. If you guys are just doing all these performance mods just for kicks, well that's kool too. I just would like to see what I'm getting before i buy

 

[JennaBear]

I have tons of dyno graphs, but we only use load bearing dynos for tuning, as we aren't interested in DynoJet numbers. If you check out performancetrucks.net, quite a few of our customers have posted their before/after time slips as well as what their current set ups are running.

 

[gtbigup01]

I have tons of dyno graphs, but we only use load bearing dynos for tuning, as we aren't interested in DynoJet numbers. If you check out performancetrucks.net, quite a few of our customers have posted their before/after time slips as well as what their current set ups are running.

Thank you, will chek them out and probably hit you up later for my special tune also