E85: A word to the wise
 

Over the last 3 months or so, I've been "playing" with E85 tunes from two different Ecutek tuners. This has been a good thing, regardless of the power gains, since it has taught me quite a bit about corn juice. I've traditionally been a pump gas guy just like many of you.

One of the problems that I have discovered is how incredibly inconsistent e85 stations are with their Ethanol content. Not only have the stations not known what the actual content is, E70 or E85 (70 to 85% ethanol), but in some cases I have been told that it is E70 only to find out I pumped E85 or something close to it. This can be bad for many reasons. I've been told that you can and should measure Ethanol content before loading the appropriate tune, but the cheap way of doing this using a glass cylinder, some distilled water, an E?? sample and a stopper is not practical at all since you will pretty much need to do this every time you fill up. That is if you wish to run E85 full time such as myself. You can't trust the E85 schedules (class 1 (79) , 2 (74) , 3 (70)) that are posted on various Internet websites for each state. I repeat, these are not accurate. Some stations have blender pumps that show a minimum 70% 105 octane rating, but they can't actually tell you the TRUE state of the content. It could even be close to E90!

A recent trip to the dyno on an E70 tune led to a power loss because of a lean condition (~13.5 AFR at WOT). I ended dyno testing after the 3rd run. Apparently I had E85 in the tank. Thank god alky is forgiving. I've found that it has cooling properties and lower EGT's better than pump and resists detonation.

Moral of the story: make your life easier and protect your motor. Get an Ethanol Content Analyzer (ECA) from Zeitronix or whomever. This will hook up to your fuel system and comes with a digital display that you run to your cabin. It will show you the Ethanol content in your tank.

I'm not suggesting that people not use E85. Just be careful and take appropriate steps before going WOT.

aaaaaand that's why actual flex fuel cars have an ethanol sensor or a software model to determine ethanol content

This is why if I go with E85 it will be a true flex fuel setup.

are you filling up at the same station every time?

A good tuner with a standalone can allow for this in the tune, you will err on the safe side with timing but still reap 90% of the gains of E85.

The best case scenario is running a ECA with a feedback loop to the ECU (standalone or otherwise) that accounts for the Ethanol Content and blends the maps accordingly. you should essentially have a 91 map and an E92 map and it will be a predictable slope between the two as far as timing and fueling go so that they can be interpolated between, there are only a couple options for this currently, but most companies are working on or just now releasing firmware that will handily...handle...this task. I believe even ECUTek is developing a "flex fuel" version of software for our vehicles.

Yes and no. I use whatever station is available when I need to refuel. All of the stations here post the same info on the E85 pumps and say the same thing verbally about E85. They don't really know and I will never again trust what comes out of their mouths. An ECA will tell the truth.

Supposedly, Ecutek flex fuel is already available. The flex fuel maps exist. I have yet to see any real penetration of this technology in this market.

Regardless, I'm at the point where I am taking my tuning needs locally using whatever tuning solution the local tuner prefers. It's safer and more convenient that way. Just my opinion! Not a knock on anybody!

@Visconti I'd like to hear John's 2 cents on this

I was only asking because I just purchased an e85 tune, and I only have one station near me that has e85. So I will be filling up at that same station every time.

Did you do any data testing in regards to going to the same station and seeing if the content is consistent?

@CBR600RR .. John is aware of my situation and he has my logs. He kindly let me know that I should be testing my ethanol content. I agree with him. That's why I'm buying an ECA.

John has done nothing wrong. He is a good tuner. The responsibility is on me to verify the quality and the content of my fuel.

if you ran the e85 tune with e70 fuel what would the result be? running rich?

Yup. The higher the ethanol content, the more fuel required to maintain AFR.

Sometimes I'm glad there's no E85 in CT. Takes the choice away from me......

I do not have this data. In addition to what I've learned, I've also been told by different tuner shops/mechanics that blindly pumping "E85" without testing is asking for trouble. E85 pumps don't exist for tuners. They exist for FFVs. They are under no real obligation to guarantee the precise ethanol content because they know FFVs can deal with it. A pump gas car on a fixed tune geared towards performance will not be so forgiving. There are numerous other forums out there that have been discussing this for years.