My FB is now on E85!

[Kentetsu]

I ran the first 3 gallons of E85 through the FB. It's 85% ethanol (corn around here) and 15% gas for "104" Octane (the RON is 114 though). After tons of reading about E85 and it's effects (alcohol eats rubber, need 20% more E85 for the same amount of gas, etc) I decided to run a few gallons through to "see what happened".

Observations:

* Cold start up was easier. It is a 230K mile 12A but it "caught" quicker and generally seemed happier. Hot start up was much improved.
* Performance (by the seat-of-my-pants) seemed better. Not loads better, but there was definite improvement. Maybe even just smoother?
* Mileage does drop. Granted 3 gallons around town wailing on it is pretty lousy anyways, but expect to see a 15-20% drop in mileage.
* Tip-in was worse. (The reaction of the engine/carb as you first touch the throttle). It's always had a "slight" hesitation from idle, the E85 made it more pronounced. Re-jetting of the carb all the way around (and honestly probably a rebuild too) needs to happen.
* Cooling was improved. My RX-7 has never run "hot" anyways, but there was a marked improvement in keeping the temp down cruising around. Cooler fuel = cooler engine.

So is it worth it? I don't know yet. With the decreased fuel mileage the cost savings isn't there. The hot-start and cooling benefits are worth it if I can cure the tip-in, I will admit. E85 is well proven on boosted applications, but the N/A 12A doesn't "need" the 104 Octane (though carbon buildup, etc might play into mine). For now I'm going back to regular 87, but if I ever rebuild the carb or swap another one (or go boosted) I think I'll be back.

[P71]

I ran the first 3 gallons of E85 through the FB. It's 85% ethanol (corn around here) and 15% gas for "104" Octane (the RON is 114 though). After tons of reading about E85 and it's effects (alcohol eats rubber, need 20% more E85 for the same amount of gas, etc) I decided to run a few gallons through to "see what happened".

Observations:

* Cold start up was easier. It is a 230K mile 12A but it "caught" quicker and generally seemed happier. Hot start up was much improved.
* Performance (by the seat-of-my-pants) seemed better. Not loads better, but there was definite improvement. Maybe even just smoother?
* Mileage does drop. Granted 3 gallons around town wailing on it is pretty lousy anyways, but expect to see a 15-20% drop in mileage.
* Tip-in was worse. (The reaction of the engine/carb as you first touch the throttle). It's always had a "slight" hesitation from idle, the E85 made it more pronounced. Re-jetting of the carb all the way around (and honestly probably a rebuild too) needs to happen.
* Cooling was improved. My RX-7 has never run "hot" anyways, but there was a marked improvement in keeping the temp down cruising around. Cooler fuel = cooler engine.

So is it worth it? I don't know yet. With the decreased fuel mileage the cost savings isn't there. The hot-start and cooling benefits are worth it if I can cure the tip-in, I will admit. E85 is well proven on boosted applications, but the N/A 12A doesn't "need" the 104 Octane (though carbon buildup, etc might play into mine). For now I'm going back to regular 87, but if I ever rebuild the carb or swap another one (or go boosted) I think I'll be back.