does anyone know if it is ok to run E 85 fuel rather than premium in the 2000 ssei?

Thanks,

NO, it is NOT ok

http://www.bonnevilleclub.com/forum/...&highlight=e85

It would be an instant death to the fuel system for sure....And I'll bet the egine would be a whole nother story.

The sadistic part of me what love to hear what happens when you put that garbage in your car but the nice guy in me would hate to see a perfectly good car destroyed to save a few pennies on fuel.

And actually, running cheaper grade fuel is actually more expensive, not only when you ruin your engine, but because of the gas mileage.

Even in cars that CAN take the cheap stuff... in general, you will get better mileage with the better fuel. It really will cost less money per mile to run.

You're partially right in reference to low octane gasoline, especially if we're talking about an SSEi. A car that requires a certain octane will often run less efficiently on a low octane fuel because of uncontrolled burn in the cylinders and the resulting knock. Even in our cars, where timing is pulled to combat knock, you'll often have lower fuel mileage when you're not running at full timing.

Cars that can take 85 or 87 octane, however, will generally not run better on mid grade or premium. Higher octane means the fuel is harder to burn, so a car running on 93 octane that was designed for 87 octane will have a tough time extracting all the energy potential out of premium gas. For example, stock L36s will often see better mileage on 87 octane than on 93, because their design and compression ratio is optimized for regular gas.

HOWEVER..... this is all irrelevant, because the original post was inquiring about E85 Ethanol blend (85% Ethanol, 15% gasoline), not 85 octane gasoline. They are two very different beasts, and should not be confused. E85 is not safe to run in a Bonneville unless it has been converted to run E85 with aftermarket parts. The fuel system, PCM programming, injectors, etc. would not be able to handle E85, and you run the risk of damaging the motor if you try to put the stuff in your tank.

E85 isn't exactly garbage. With the correct parts and engineering, it is a high performance fuel. The octane rating is something like 110. It is a legitimate fuel... it just doesn't have widespread applicability at this time

I actually get better mileage with 91 octane as opposed to 87 with my L36 powered GM car. Also an increase in performance, due to less KR I'm assuming. :o

You may get better mileage with 91, but I'm speaking in generalities. For the most part, an average car that'* designed to run on 87 will not get better mileage with a more extreme jump, like 93 octane. Some stock L36s are known to have some KR, so if you're using the lowest octane possible while avoiding knock, you're probably running in your motor'* sweet spot.

Basic rule of thumb with octane is to run the number that keeps you from detonating/knocking, but not very many points above that level. You want your engine to be able to extract all the possible energy from the fuel, and if you're putting in super high octane numbers, the fuel burn won't be as complete.