EVO9, E74 and why you need a fuel tester
The lowest I've seen is E70.
That must be what I was remembering Tim, I knew we changed fuel three times, I thought we tried E85 in there. Thanks for the correction.
I can't wait to up run my first batch of ethanol! I'll have to do a thread on it with pictures when I do.
That must be what I was remembering Tim, I knew we changed fuel three times, I thought we tried E85 in there. Thanks for the correction.
I can't wait to up run my first batch of ethanol! I'll have to do a thread on it with pictures when I do.
The RFA (All of America) guidelines state E85 must be 70-79% Ethanol to hydrocarbon %. Which fits neatly into the Retail Class system that some people know of:
Class 1 : 79%
Class 2: 74%
Class 3: 70%
Which means what the minimum Ethanol % is *required*. So Class 1 can be 85% Ethanol but not less then 79% Ethanol.
dave just said that most standalones like aem have the Capability does anybody tune using the 02 feedback and a flex fuel sensor. I think that for those of us who dont have E85 everwhere yet or use there evos as a dd and may go on long trips that it would be worth it.
on a few standalones you can run closed loop at wot, but its a bad idea for a few reasons. one being that there is only so much it can adjust the trims (ex: +/- 5%). another is if the o2 sensor starts going bad its blown motor time.
Can't release that info, just yet 
. But do understand I am not lying. All last year even thru the winter it was E90. Early this year it went up to E93 and this November it went down to E87. I keep two testers. One always in the talon and the other in my daily. When I know i'll be driving frequently around a certain area I test the E85 as I fuel the daily. All it takes is 8cents of E85. Why not? That's how I found a few spots. Isn't a couple a minutes of your time worth knowing you're going from E70/E85 to E93? Or vice versa?
This is what i use.
http://www.quickfueltechnology.com/s...test-tube.html
. But do understand I am not lying. All last year even thru the winter it was E90. Early this year it went up to E93 and this November it went down to E87. I keep two testers. One always in the talon and the other in my daily. When I know i'll be driving frequently around a certain area I test the E85 as I fuel the daily. All it takes is 8cents of E85. Why not? That's how I found a few spots. Isn't a couple a minutes of your time worth knowing you're going from E70/E85 to E93? Or vice versa? This is what i use.
http://www.quickfueltechnology.com/s...test-tube.html
Only reason I asked is that I think you're local to me, but it really doesn't matter as I only go to the 2 stations by my house.
Good information Bryan. The lowest tested I've seen here is E70.
You guys have to understand that fuel trims are only part of the equation, you also will need a timing adjustment if there is a large change in ethanol content. The largest change should be 15%. I think if I had to do one tune and make the car live I'd make some E77 and tune the car. This would put the car In between the worst and best fuel you could get. At that point I feel you'd have nothing to worry about. The 02 feedback would take care of your idle/part throttle etc. At WOT your AFR's if you tuned the car in, say the 11.7:1 range would be safe in either direction. I'd say that is the best advise I can give and would work really well.
BTW, a stand alone can correct fuel mixtures by a LOT, +/- 25% for example. I'd certainly never want to rely on it correcting that much but it's possible. I prefer to tune so the corrections being made are always pulling fuel out and then less than a 5% correction.
You guys have to understand that fuel trims are only part of the equation, you also will need a timing adjustment if there is a large change in ethanol content. The largest change should be 15%. I think if I had to do one tune and make the car live I'd make some E77 and tune the car. This would put the car In between the worst and best fuel you could get. At that point I feel you'd have nothing to worry about. The 02 feedback would take care of your idle/part throttle etc. At WOT your AFR's if you tuned the car in, say the 11.7:1 range would be safe in either direction. I'd say that is the best advise I can give and would work really well.
BTW, a stand alone can correct fuel mixtures by a LOT, +/- 25% for example. I'd certainly never want to rely on it correcting that much but it's possible. I prefer to tune so the corrections being made are always pulling fuel out and then less than a 5% correction.
this thread is great...there are 2 places here in Mansfield who have e85(that i know of) I try to just stick to the one close to my house, but that might change. Thanks for all the information, you can bet your *** ill have a tester and pay much closer attention to whats going in my tank when I get my car back on the road.
wow! im really only familiar with hydra ems and its been a couple years. i didnt know they could correct that much. at least with the hydra, it didnt care for large corrections at all.
The GM flex fuel sensor does not have a linear voltage output. It is a PWM output that gives data about ethanol content AND fuel temperature. I Think the frequency is proportional to the ethanol content and the duty cycle proportional to temperature, but it could be the other way around.
Interestingly though, GM may have eliminated the sensor all together and just relies on O2 feedback to adjust for ethanol content. The ECU senses when the car is refueled and goes into a specific calibration mode to determine Ethanol content.
Interestingly though, GM may have eliminated the sensor all together and just relies on O2 feedback to adjust for ethanol content. The ECU senses when the car is refueled and goes into a specific calibration mode to determine Ethanol content.
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