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E85 how to tune it?


Cordell

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I'm seriously considering changing cylinder heads on my car (was going to do anyway) and I want to increase compression a lot without having to buy race gas. E85 seems like a great way to play with a combo like this. I understand that E85 requires more fuel somewhere in the neighborhood of 25% more, and relavant to that has a much "richer" A/F ratio for stoich. It seems the only thing I can't find much info on is how it is to be measured accuratly. I use an Innovate LC-1 now, it works fine for gas. How would it work for Ethanol? Does anyone have personal experience with this and how's it go? I've seen Thorne's thread about his results and this has sparked more interest for me, any input is appreciated.
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I'm not sure what outputs the LC-1 has, but I figure it has a lambda output as well as AFR. It's sort of personal preference as to how you want your readout to be. When I first switched over, I was used to looking at AFR so I kept it that way and eventually switched over to lambda.

 

If you decide to use the AFR reading, then basically you are shooting for the same AFRs as gasoline except more power can be made with ethanol when you are on the rich side. For example, if you made best power at 13.2:1 on gasoline, with ethanol it may be at 12.8:1. I'm just throwing out numbers for example.

 

That was probably confusing.

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I'm not sure what outputs the LC-1 has, but I figure it has a lambda output as well as AFR. It's sort of personal preference as to how you want your readout to be. When I first switched over, I was used to looking at AFR so I kept it that way and eventually switched over to lambda.

 

If you decide to use the AFR reading, then basically you are shooting for the same AFRs as gasoline except more power can be made with ethanol when you are on the rich side. For example, if you made best power at 13.2:1 on gasoline, with ethanol it may be at 12.8:1. I'm just throwing out numbers for example.

 

That was probably confusing.

 

Well the LC-1 is just that a Lambda cable, so it outputs a 0-5v signal based on Lambda, and is just converted into AFR in the gauge. So are you saying that target lambda is the same for both? Obviously because of the different fuels "optimum" lambda is slightly different, but the wideband would just see the same thing? I guess this would make sence since the wideband is just measuring burnt fuel.

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i can tell you to overshoot and go too rich. then back it up.

i have had no problems i run my turbo at 6.8 wot and its wanting more fuel. with the msd digital 6 and hvc2 coil. i cant feed it enough stoich for e85 is 9.76 wot rich is 6.7 wot lean is 7.3. so i make damn shure im richer than 7.3 but at 6.7 my autometer gauge is burried and it wants more fuel. that could be because its carbed and the fuel is acting like a intercooler too. the innovate will tune for e85 for shure. ibelieve the stoich for it on a gas meter in lamda is 1.1 think i read that somewhere but i dont use lamda

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Yes, that's why learning lambda values makes life easier because it's the same across the fuels. 1 lambda is stoichiometric for gasoling, E10, E20, E85, E100, or whatever. It's always the same.

 

lambda = AFR / AFR stoich

 

So when your gauge is reading 14.7 with E85, then you are at stoichiometric conditions because that's a lambda of 1. Though, technically the actual AFR with E85 would be ~9.87, but the wideband controllers gives you gasoline AFRs.

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my wideband lets you change stoich to whatever fuel type. so my 14.7 is set at 9.7 and it shows digital values up and down from there also records 20 sec for wot pulls and tell me the leanest it gets. wich dont work on the two step so i have to roll out on the foot and then go wot to get a good reading.
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its the autometer wideband gauge. dosent have a freeair calibration like the innovate but it works well. i couldnt get the innovate to work something with the grounds proably was very jumpy and couldent get a constant reading on any one number.
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Step 1

BIG ASS INJECTORS

 

 

I don't know on other cars but on a subaru you can scale your injectors by 33% and dial it in closer with a wideband. I have a LC-1 I targeting 11.5-12ish. I went leaner and lost power.

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ill bet the car will pick up. at least for track use then you can lean it out some on the steet. i still havent got enough fuel to mine and it picks up mph each time i add more. its got to slow down sooner or later.
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Is there much to be gained from e85 on NA setups? The nice thing about e85 is that it burns cooler and eats up timing which is ideal for turbos.

 

I know that on my setup and on 93 oct, 42# injectors and stock fuel pump is enough. But for e85 I have to run a 255pump and 60# injectors.

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Running it NA would be beneficial, but I wouldn't imagine it to be worth it until you need to run around 100 octane like with higher compression. It would also make sence to me that running nitrous would benefit the same way, but would require much bigger jetting.
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