[jcaligood]

Just ordered a flex fuel sensor, and will be getting tuned for E85 soon.

Recently I watched a video of a horror story (itsjusta6 on youtube)
He was tuned for E85 and got a bad batch of E85 that he didn't test before using in his mustang. I'm under the belief they do not have flex fuel sensor availability for the mustangs.
Anyway, the ethanol content of that E85 was actually around E70 or something like that. It caused predetonation and catastrophic failure of his engine.

My question is, with the flex fuel sensor, it tells our ECU the true ethanol content of the fuel being used, correct? And the ECU uses different maps based on the ethanol content.

Along with a dyno tune for E85, will the flex fuel sensor still correct the ECU and timing for the actual ethanol content being used?
If so, what is an ethanol % that is something to worry about using in our cars?
Say E65.. would it still be okay to run while being tuned for E85 with a flex fuel sensor?
Also, are there any Android apps for bluetooth OBD2 dongles we can use to monitor ethanol content?

Also storing E85, won't the ethanol content decrease over time? And water moisture can be attracted to it if stored for a few weeks?

Any info to help me better understand E85 before being tuned for it will be greatly appreciated.
Thank you Camaro6 brothers.

[kropscamaro16]

yes you dont need to test it unless you want to but i have heard you are not suppose to store e85 for along time and leave it in your tank along time either

[s346k]

e85 is simple for those of us with mild na cars

-we won't see much power gain over e60, meaning the tune for e60 is gonna be almost identical to the tune for e85
-the content sensor gathers the info
-the ecu applies the correct timing/fuel maps for the content
-the tuner is responsible for defining those maps
-it has sat in my car up to 2 months with no ill effects

do yourself a favor and research the seasonal and geographical volatility classes for ethanol

for some reason there is still a lot of misinformation about ethanol. it's not rocket science nor is it new technology. it's alcohol. alcohol has been used as a fuel for engines since the 1800s.

edit: the best thing you can do is find a competent tuner that actually uses/has used ethanol in their own car. they will have the answers to every question you can come up with.

[KingLT1]

If you don't have a flex sensor then yes you need to test the E85 you pump because it often varies and almost is never true E85 at the pump. However if you have a Flex sensor with proper tune then you don't have to worry about it. The sensor reads the ethanol % in the fuel and sends the reading to the ECU. Then the ECU adjusts the AFR and timing as needed.

Far as what is a good Ethanol percent...well actually E60 is the sweet spot between being able to run optimal timing, less taxing on the fuel system, and nets a little better fuel mileage compared to full E. Either way with a proper tune you should be able to run up to E85 with no issues and if for some reason you were around E40 due to mixing some 93 in, the ECU might pull a degree or 2 of timing to compensate for the lower octane.

I have stored my car with anywhere from E50 to E70 in my tank over the winter in a climate controlled shop and never had any issues with moisture. That mainly applies if the car is going to sit in a area with large temperature fluctuations.




Full E85 is 109-110 octane

E60 mixed with 93 is around 105-106 octane

E40 mixed with 93 is around 100-101 octane


So as you can see anything from E40 on up provides a nice octane bump and will show some decent gains.

Not sure why Itsjusta6 wasn't testing his E. Since he didn't have a sensor and was tuned specific amount of Ethanol % then he should of been buying C85 by the drum for that car since he didn't have a flex tune.

[jcaligood]

I appreciate the detailed responses, everyone.
Thanks for the relief.

I'll let ya know how the tune goes afterwards!