So my truck is not flex fuel ready. Is there any good reason not to run E85? I have a Hypertech programmer and already have it set to premium fuel. That's all I run. I think it should compensate for the higher octane rating in the E85.

 

I think the seals and O-rings and such has to be compatible with E85 for you to be able to run it, and if you ignore that you'll soon have leaks through just about every single seal that touches fuel. There might also be some issues with the fuel pump being incompatible with E85, but not sure. I looked into it briefly once and quickly saw that it was way too much headache to convert it into a E85 compatible configuration that it would make more sense to just sell it and buy a newer one that is already made for it.

 

Yes, there is a good reason. Your truck wasn't made for it. Period.

That's besides the issue of the foolishness of the government-mandated diversion of a foodstock into the energy supply stream, despite our swimming in both oil and natural gas as a result of the fracking boom and increased energy production here in the US and Canada.

 

Destroying your motor should top your list of reasons.

 

I hear ya, but I am looking for the actual why and what would happen. There is a lot of mixed data out there.

 

The data isn't mixed, it is extremely clear.

E85 vehicles have fueling systems that are designed from scratch to withstand the corrosive effects of the extra alcohol, an E10/E15 vehicle does not.

E85 vehicles have a sensor that measures the alcohol concentration and automatically adjusts the operating parameters to accommodate it, non-FFV vehicles do not.

Can you run it? Sure, but be prepared for any consequences. It might run poorly, it will likely set "lean" codes and a MIL, and you'll run out of gas a whole lot sooner. A one-off incident won't carry much of a risk of permanent harm.

 

The decrease in MPG should be enough of a reason. We have a 2010 E85 fusion we tried E85 fuel on a 400 mile road trip and it dropped our mileage from 31 to 24.5. We ran the tank as close to empty as we could put regular 87 octane fuel in it and after 75 miles it was back in the 30-32 mpg range. To me with the lower gas price e85 isn't worth it. As far as your non e85 vehicle goes I tried it in my f150 a couple years ago ended up messing up a couple injectors and the O2 sensors. And it just ran like crap.