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Old 12-12-2006, 12:57 PM   #1
akira02rex
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Default Anyone doing E85 tuning yet?

I havn't found anyone post dyno numbers with 100% E85 yet.
I made up a quick fuel map in Enginuity for running 100% E85.
I basically took all my target A/F values and multiplied by 0.66 (66%). The result is about 9.7:1 during cruising (14.7 gasoline) and mid 7:1 for WOT.

I have plenty big enough injectors as well.

For my first few runs I will probably back off the boost to about 15psi or so.
I can't wait as I am anticipating some pretty good results with this stuff!
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Old 12-12-2006, 02:07 PM   #2
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Nice, I'd be tuning with it if I could get it easily. 105 octane FTW And thats not counting how much cooling the fuel adds. But currently it is a 200 mile drive to get to E85, which I've only done once and brought back 12 gallons for my RS. I didn't drive out there for the fuel only though, just happened to be going to that town anyway.
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Old 12-12-2006, 03:50 PM   #3
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Quote:
Originally Posted by akira02rex View Post
The result is about 9.7:1 during cruising (14.7 gasoline) and mid 7:1 for WOT.

which would be great if the a/f sensor read below 11.0 to 1
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Old 12-12-2006, 05:27 PM   #4
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Quote:
Originally Posted by akira02rex View Post
I havn't found anyone post dyno numbers with 100% E85 yet.
I made up a quick fuel map in Enginuity for running 100% E85.
I basically took all my target A/F values and multiplied by 0.66 (66%). The result is about 9.7:1 during cruising (14.7 gasoline) and mid 7:1 for WOT.

I have plenty big enough injectors as well.

For my first few runs I will probably back off the boost to about 15psi or so.
I can't wait as I am anticipating some pretty good results with this stuff!
I don't think that your approach is going to work very well as your long term fuel trims are going to get pegged and basically flood the car in open loop.

The fuel maps in Enginuity are based on gasoline AFRs, but the ecu likes to think in terms of Lambda.

So here's what I'm thinking would work:

- fill up on e85 while on an empty tank
- richen up your high load targets a bit (maybe something like 10:1) since max torque rich of e85 has a bit lower Lambda than gasoline does
- divide your injector scaling by 1.25 (this is assuming that the injector will need to flow approx. 25% extra volume of fuel, I don't know what the exact amout is)
- flash your map and start up the car (pray it starts )
- let the car idle and come up to operating temp
- once operating temp is reached, reset the ecu and then shut down and restart the car
- now let the car idle for a good 10 minutes or so and watch your short- and long-term fuel trims and wait for them to stabilize

- now here's the important part:

- if the combined total of your LTFT and STFT is a positive % (say 7%), then divide your current fuel injector flow scalar by 1.07 in this example
- if the combined total is a negative % (say -7%), then divide your current fuel injector flow scalar by 0.93 in this example.

This should 0 out your fuel trims and thus your low-det fuel table (which is simply a Lambda table, but expressed in gasoline afrs) should be as accurate as when you were running gasoline.

I have yet to try this since I don't have a wideband (yet), so take my advice with caution. Also, I would only try this while using a wideband and BE SURE TO SET THE WIDEBAND TO READ IN LAMBDA.

Have fun, and let us know of your results!

Last edited by wall of tvs; 12-12-2006 at 05:33 PM.
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Old 12-12-2006, 05:43 PM   #5
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Quote:
Originally Posted by Jaxx
which would be great if the a/f sensor read below 11.0 to 1
You are deeply confused because he is talking about actual Ethanol AFRs. A 9:1 AFR on E85 would show up near 14.7 on the stock A/F sensor.
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Old 12-12-2006, 05:52 PM   #6
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^^^ Correct. The sensor operates by reading Lambda, but the programs we use convert this lambda reading to a gasoline-equivalent AFR.

I REALLY wish fueling was discussed in terms of Lambda as AFRs confuse everyone, lol.

Also, people need to realize that AFRs are based on MASS not volume.
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Old 12-12-2006, 06:08 PM   #7
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Quote:
Originally Posted by wall of tvs
^^^ Correct. The sensor operates by reading Lambda, but the programs we use convert this lambda reading to a gasoline-equivalent AFR.

I REALLY wish fueling was discussed in terms of Lambda as AFRs confuse everyone, lol.

Also, people need to realize that AFRs are based on MASS not volume.
I agree. I've never heard of AFR being based on Volume though. It is a ratio of air weight to fuel weight. in the case of Gasoline, stoic would mix 14.7 pounds of air with 1 pound of fuel.
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Old 12-12-2006, 06:46 PM   #8
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so the same sensor configured the same way will read a lambda of 1 with ~14.7 of gas or ~9.1 of e85 .. ... by measuring the amount of residual gasses

my head hurts
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Old 12-12-2006, 11:30 PM   #9
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My Zeitronix logs both AFR and Lambda.
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Old 12-16-2006, 05:01 PM   #10
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Won't the ethanol degrade parts unless they are designed to handle it?
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Old 12-16-2006, 08:36 PM   #11
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Quote:
Originally Posted by Jaxx View Post
so the same sensor configured the same way will read a lambda of 1 with ~14.7 of gas or ~9.1 of e85 .. ... by measuring the amount of residual gasses

my head hurts
Yes, that's the way wideband/O2 sensors work.

The OEM ECU's fuel enrichment tables are, internally, target fuel/air equivalence ratios. An internal value might be 25, which means make the fuel/air ratio 25% richer than stoichiometric. That means the target fuel air equivalence ratio is 1.25 and it means that target lambda (the inverse of fuel/air equivalence ratio) is 1/1.25=0.80.
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Old 12-17-2006, 09:56 AM   #12
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So does anyone think my approach will work?
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Old 12-17-2006, 10:57 AM   #13
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I've already stated my opinion. See post #4 above.
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Old 12-19-2006, 12:31 PM   #14
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I know
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Old 12-19-2006, 02:42 PM   #15
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Quote:
Originally Posted by Dentspeed
Won't the ethanol degrade parts unless they are designed to handle it?
Read this
http://forums.nasioc.com/forums/showthread.php?t=803341

technically the parts were already designed to handle atleast 10% ethanol.
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Old 12-20-2006, 05:39 PM   #16
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Quote:
Originally Posted by akira02rex View Post
I know
hehehe....sorry. I guess nobody ever responded to what I wrote so I wasn't sure if it was taken into consideration.

I'm 99% certain that the correct way to tune for e85 is to adjust your injector scalar. I just ran across this recent post that pretty much sums up my train of thought on how the fueling of the car works: http://forums.nasioc.com/forums/show...4&postcount=28
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Old 12-21-2006, 04:52 PM   #17
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stolen from klaus at innovative

Quote:
AFR is Lambda * stoich value of fuel.

Lambda is independent of fuel value.

If the engine develops max power at 0.82 Lambda, it would also develop max power at that Lambda with E85 (or close to it).
0.82 Lambda with race-gas is 12 real AFR (14.7 * 0.82). With E85 the "real" AFR is (9.7 * 0.82) = 7.92 AFR. When leaving the LM-1 set to gasoline, it will show instead 12.

For tuning purposes most people don't bother with changing to the correct stoich value, as they are used to the gasoline AFR numbers.

The fuel flow to reach that "gas" AFR is if course very different.

Also, don't forget: the ign. timing curve should be optimized for E85, as the burn characteristics of alcohol are different than gasoline.

Regards,
Klaus
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Old 12-21-2006, 05:15 PM   #18
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using the chart from the e85 faq
E85 stoich 9.765 0.10235 1 1
E85 Max power rich 6.975 0.1434 1.40 0.7143
E85 Max power lean 8.4687 0.118 1.153 0.8673

so that means that if you had 100% e85 and a wideband configured for gasoline

stoich 14.7
max power lean 12.74 <---this number seems high too me
max power rich 10.5

Last edited by Jaxx; 12-29-2006 at 12:13 PM.
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Old 12-23-2006, 04:55 PM   #19
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I don't think you need to adjust your fuel map that drastically- I would set your intake calibration back to stock, then adjust your fuel injector scalar so that the car idles and both the long and short term trims are 0% (or as close as you can get).

From there, calibrate the intake as best you can and see what kind of trend you are seeing in the values. After doing this, I think your fuel map will need little to no modification since as Jon explained, the maps are based on a percentage addition or removal from stoich. If that's the case, adjusting your fuel injector scaling should give you the correct results I think.

Good luck!
Mike


Quote:
Originally Posted by akira02rex View Post
I havn't found anyone post dyno numbers with 100% E85 yet.
I made up a quick fuel map in Enginuity for running 100% E85.
I basically took all my target A/F values and multiplied by 0.66 (66%). The result is about 9.7:1 during cruising (14.7 gasoline) and mid 7:1 for WOT.

I have plenty big enough injectors as well.

For my first few runs I will probably back off the boost to about 15psi or so.
I can't wait as I am anticipating some pretty good results with this stuff!
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Old 12-27-2006, 11:38 AM   #20
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send me a 55gal drum and i'll test the crap out of it.
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Old 12-27-2006, 02:47 PM   #21
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Just thinking about this, I myself honostly think the way I am doing this is perfectly fine. The Target A/F map is just an X/Y coordinate full of numbers that represent how much fuel to give the engine.
E85 obviously takes ABOUT 66% more fuel to run properly compared to gasoline. Am I thinking too simply here?
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Old 12-27-2006, 02:56 PM   #22
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When I look at the table, I think of it as lamba, not afrs. When I see 12.5, I think .85 lambda. If I see 9:1, I think holy crap, a lot of fuel.

I'd personally calibrate the fuel injector scalar and intake rather than make the fuel table changes, but that's me.

I honestly thing either way should work.


Mike
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Old 12-27-2006, 03:43 PM   #23
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Quote:
Originally Posted by akira02rex View Post
Just thinking about this, I myself honostly think the way I am doing this is perfectly fine. The Target A/F map is just an X/Y coordinate full of numbers that represent how much fuel to give the engine.
E85 obviously takes ABOUT 66% more fuel to run properly compared to gasoline. Am I thinking too simply here?
You are WAY off base.

You need to get injector scaling correct and then everything else will take care of itself.

Internally, the injector scaling value represents the amount of time the injector must flow fuel in order to get a stoichiometric A/F ratio when presented with one gram of air. This value is affected by three things: injector size, fuel density and fuel stoichiometric A/F ratio. When you scale the injectors correctly, such that absolute long term fuel trims are minimized, then you shouldn't need to modify any other tables to achieve good results.
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Old 12-27-2006, 04:26 PM   #24
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Ok, that makes sense.
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Old 12-27-2006, 04:29 PM   #25
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Quote:
Originally Posted by crazymikie View Post
When I look at the table, I think of it as lamba, not afrs. When I see 12.5, I think .85 lambda. If I see 9:1, I think holy crap, a lot of fuel.

I'd personally calibrate the fuel injector scalar and intake rather than make the fuel table changes, but that's me.

I honestly thing either way should work.


Mike
either way will work until your long term fuel trims are learned and then the car floods itself in open loop if the tuner only modifies the fuel table.
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