My RX-7 has been successfully converted to burn Ethanol. It is using a 70/30 gasoline/E85 mix. Not only does this run cooler, allow for more boost (the but-dyno prooves 50 more horsepower) but it’s lower emissions. The only downside is that there only 650 E85 stations in the US. The nearest one is in denver (boulder soon tho!).

So my rice rocket is now on a steady diet of corn.

All that was necessary for me to do was to tweak the PFC settings to richen the mixture. I simply indicated a smaller injector than my 1300cc which widens the pulse and increases the duty cycle of the injector. This allowed me to move my boost from .74 peak to .86 (about 12.5psi to 15psi). The knock level actually went down at the higher boost levels with ethanol. Note: I am running J-spec twins.

As for the corrosion issue. I have a number of subie people who have dissassembled entire fuel systems and found no excess wear. At lower level blends it is not problematic unless you get water mixture in the fuel, then it's a problem:
"
E85 can cause damage, since prolonged exposure to high concentrations of ethanol may corrode metal and rubber parts in older engines (pre-1988) designed primarily for gasoline. The hydroxyl group on the ethanol molecule is an extremely weak acid, but it can enhance corrosion for some natural materials. For post-1988 fuel-injected engines, all the components are already designed to accommodate E10 (10% ethanol) blends through the elimination of exposed magnesium and aluminum metals and natural rubber and cork gasketed parts. Hence, there is a greater degree of flexibility in just how much more ethanol may be added without causing ethanol-induced damage, varying by automobile manufacturer. Anhydrous ethanol in the absence of direct exposure to alkali metals and bases is non-corrosive; it is only when water is mixed with the ethanol that the mixture becomes corrosive to some metals. Hence, there is no appreciable difference in the corrosive properties between E10 and a 50:50 blend of E10 gasoline and E85 (47.5% ethanol), provided there is no water present, and the engine was designed to accommodate E10. Nonetheless, operation with more than 10% ethanol has never been recommended by car manufacturers in non-FFVs.
Operation on up to 20% ethanol is generally considered safe for all post 1988 cars and trucks.
"

So my next step is to increase the blend to 50/50 and see about getting the turbos to hold boost across to redline.

I'll continue to update status for those who are interested in converting. As it sits it's the cheapest speed mod I've found for the car.

 

Have you been running it long enough to know how it affects your MPG? Also, what are the prices of ethanol these days?

 

wow, i like this. not sure where to get e85 yet though.

 

ive been waiting for E85 for my rotary project only there isnt a station closer than a 2 hour drive. sigh.

but can you elaborate on the 50/50 mix to "keep boost to redline?" Is the 70/30 causing high end boost issues?

 

This is good news. If we can run the FD on alternative fuels, we wont have to abandon our cars when the dino juice finally expires

 

anyone know how carbs might respond to high ethonal content fuels? in terms of corrosion.

 

Are you checking all this against a wideband?

Dave

 

http://www.e85fuel.com/database/search.php for all interested in locations. the illinois people are lucky. they have by far the most stations.

 

So you didn't change any fuel system components?

That's been my major concern in running ethanol in my truck. Corrosion.

 

one station that is getting it near me is charging 20 cent more than premium. but if it takes more fuel to reach stocih, its more expensive then in terms of mileage. meaning it better up my preformance when properly tuned and until i make my still and make my own.

 

E85 is 85% ethanol and 15 gasoline, that is why it is called E85.

 

Exactly.. You're basically running E25.

 

Prices for E85 tend to be about 15-20 cents cheaper per gallon in the suburbs of Chicago.

 

the est price here was 20 more per gallon when we get it. i think the tenant lady was just a moron.

 

just wanted to point out that the pfc uses kg/cm^2 to measure boost, and .74 equates to just under 11 psi, while .86 is just above 12 psi.

 

that could have been creep then.

 

good stuff keep us updated!

 

dyno chart for this "50hp increase"

 

Everything I've read about it say that E85 should yield less HP and worse fuel consumption.

 

Car and Driver did an article recently on E85. They're not very optimistic about it's use. It's a fairly long read but has some interesting info. Read it, draw your own conclusions.

http://www.caranddriver.com/features...-promises.html

 

From the article that ArcWelder posted:
"Differences in acceleration times were insignificant (although GM says E85 improves horsepower by as much as three percent)."

I read that article in the print copy where they had various acceleration times, and while they wrote they were insignificant, the E85 was consistently faster.

It does get less MPG however.

 

Far less MPG.

 

Ethanol has less energy potential per weight than gasoline. Bedard (the author) covered that in one portion of the text:
"Both alcohols suffer from low energy density: It takes 1.48 gallons of ethanol to equal the energy in a gallon of gasoline, and 1.87 gallons of methanol." This is why tests showed that ethanol offered markedly less efficiency (MPG) than gasoline. All things being equal, it just doesn't produce as much power as gasoline.
I don't recall where in the print version of the article they showed that E85 produced acceleration times that were "consistently faster", but I know if they labeled them "insignificant", that means that they were so small that there can be plenty of other reasons for the quicker times. Meanwhile, the significantly less MPG is a graphic demonstration of that ethanol results in less power unless steps are taken to counter that aspect.

 

Sorry took me a while to get back here, I'm running a conference and have been away for a bit.

I am by no means an expert at all in this field. I have a friend who is advising me and had converted his GVR-4 over.

E85 is less efficient in that it has less power per unit than gasoline. However, it runs cooler, and reduces knock which allows you to run more boost. so for an NA car ethanol would not necessarily allow for more power or quicker times. However, with sensitive-to-knock turbo cars like ours, it means more boost can be safely acheived.

I'm going to experiment with the blend and fuel mixtures and then I'll put it on the dyno an do the wideband thing and see what the bump in boost has proven. My last dyno session yeilded 325RWHP.

To address questions: The fuel mixture has nothing to do with holding boost to redline, I simply need to check for boost leaks as it's not holding perfectly.

Thanks for the correction goodfellas - I was referencing my PFC and an analog boost gauge. I think the difference comes in the fact that one measures absolute pressure while the other measures manifold (?). BTW - we met 2 years ago at the rotary revolution where I bought this car. We talked at the RX7trix tent while I bought a short shifter and my friend mike bought V-doors.

I'll keep you all posted as I learn more and hopefully don't blow anything up.

So far, the car seems to be happier and more powerful in the very hot summer conditions, and it seems to start and run a bit better when it's cold. But this could just be me too...

 

I work at a marina and carburated boats have a huge problem with the 10% ethanol mix. The mix causes the small pasages in the carbs to get clogged and makes mid range throttle very poor and unresponsive. The results would probably be similar with a carburated car.