Beck

Where I live, Sweden, we have something called E85 which consists of 85% ethanol. The rest is made up of gasoline and various lubricating additives.

I know that you must increase fuel pressure by ~40% to compensate for the lower energy content of ethanol. Instead of A/F 14.7 to 1 you will have ~9.6 to 1.

I'm also aware of that ethanol may damage injectors and fuel lines in the long run. Starting problems is a no issue for me since i will only drive the car in the Summer anyway.

On the other hand there are several advantages of using ethanol from an engine efficiency standpoint of view. Saab is now selling version of the 9-5 that can run on booth E85 and gas or on a mixture of them. Using E85 boosts output from 150-180HP. Now this is for a FI car. A lot of the FI performance crowd are adopting E85 for this season.

How big gains can be realized for a highly refined motor such as the Honda F20C? Assuming good tuning such as AEM EMS, bigger injectors and a fuel pressure regulator?

6sigma

We have a few sources of E85 in the US, but I've never heard of it as a performance upgrade. Here it is marketed as a homegrown alternative to middle-eastern oil. Some cars and trucks are sold as flex fuel - gasoline or ethanol up to 85%. I have been using E85 in my flex-fuel V8 truck because it is cheaper than unleaded and is made from corn which is grown and distilled nearby. E85 is currently about $1.60 per US gallon. I have noticed a marginal performance loss with E85 in my truck versus straight unleaded, but not bad. I would imagine converting a non-ethanol capable vehicle would be expensive, and without FI I can't imagine how it would improve performance. E85 does have an octane of about 105 but it has significantly less energy/unit than gasoline. The Indy cars run pure ethanol though, and they make some serious power. I do admit I like the way the exhaust smells on E85 - reminds me of a race car somehow.

Beck

You are experiencing a loss of power because your ECU is not able to add enough ethanol. You are running lean.

You have to add more ethanol to compensate the lower energy content. You also have tune the engine for ethanol. Larger injectors and a fuel pressure regulator are necessary.

Because of the higher octane level you can raise compression and advance timing quite a bit. This gives more horsepower and better throttle response. Ethanol also burns at a lower temperature. This is good for the engine itself because you don't have run rich A/F at high rpm WOT. Ethanol also supposedly contains oxygen in itself which makes combustion more efficient comparing to gasoline. As a bonus you don't get any carbon buildup inside your engine.