Thread: E15 tuning

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2014-02-18 15:37:44

#11

Mr.sentra_specv Online/offline status of Mr.sentra_specv is unknown

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Do your self a favor and just look at the lambda not the adjusted afr. Tune the n/a setup at .85-.87 for wot and around 1.0 for cruise. E85 has a stoich value of something like 9.7 and 100% gas is 14.7. If we use lambda values it doesn't matter what fuel you use because stoich is always 1.0 and best power n/a will be around .85-.87 for 95% of fuels and setups

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2014-02-19 17:11:19

#12

ebinkerd

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Originally Posted by Mr.sentra_specv

E85 and gasoline have the same Lambda values. The target lambda (afr) is different.
http://ethanolpro.tripod.com/id213.html

Last edited by ebinkerd on 2014-02-19 at 17-13-46.

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2014-02-19 20:46:29

#13

BenFenner

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I think you could benefit from reading this post in another thread:

Originally Posted by BenFenner

Just so no one is confused by VeryQuikSSS's posts, technically the car doesn't run any richer on E85. Or it shouldn't if properly tuned. Actually, because of the higher octane, you can run leaner than you normally would with gasoline if you felt like it.

"Lean" and "rich" typically refer to having more or less fuel than stoichiometric. This means that with gasoline, if you have an AFR of 14.7:1 your mixture is technically stoichiometric. With E85, as mentioned, the stoichiometric mixture is 9.765:1 which means that you need much more fuel per air molecule to reach a "perfect" combustion.

While the car will need more fuel with E85, technically it's not running "rich" as VeryQuikSSS has described. It just has more fuel.

Now, about the air/fuel ratio, and tuning. Tuning with a wideband sensor and E85 is effectively the same for both gasoline and E85 because the oxygen sensor reads unburnt oxygen, and doesn't care at all what fuel you use. If your Wideband displays lambda, good for you. You can use 1.0 lambda as stoichiometric as you always have and call it a day. You can also feel warm and fuzzy inside knowing your display is technically accurate too.

Those with displays that show air/fuel ratios instead of lambda like "14.7:1", "12.0:1" and "15.5:1" can tune the same exact way they always have as well. While technically the air/fuel ratio while running E85 might be 9.765:1, the display will show "14.7:1". This is technically incorrect, but completely useful and easily interpreted if you just assume you're using gasoline, and use the values you've always tuned to. This means that you can tune to "12.0:1" ratio on the gauge and it will result in the proper amount of fuel being delivered for boost whether you're running gasoline, E85, propane, hydrogen, etc.

Also check out these threads in general:
http://www.sr20-forum.com/vvl/41316-thinking-about-basic-e85-build.html
http://www.sr20-forum.com/turbo/13613-e-85-a.html

Last edited by BenFenner on 2014-02-19 at 20-49-58.

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2014-02-20 00:13:35

#14

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2014-03-04 20:33:19

#15

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Originally Posted by Doctor
Nothing at the pumps but we can get pure 96 ethanol from a few suppliers. And yes it's cheaper than gas. Just a hassle. I should probably try out an 85 mix. But I'd have to get larger injectors I suspect. What AFR do you tune for with e85 on aspirated?

will 96% mix with the gasoline properly? I thought to mix with gasoline it had to be nearly 100% ethanol

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