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Old 03-30-2012, 02:24 PM   #1
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986 & Ethanol

Can our cars run on E85 ie 85% Ethanol based fuel?

2000 2.7 Boxster
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Old 03-30-2012, 02:50 PM   #2
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Absolutely not.
Anything really new is invented only in one’s youth. Later, one becomes more experienced, more famous – and more stupid.” - Albert Einstein
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Old 03-31-2012, 12:05 AM   #3
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It will kill your fuel system slowly.
Ethanol is really aggressive and it will chew up most rubber parts in the system.Some metal to I guess.
It is probably possible after a thorough investigation of what parts that needs to be exchanged
As the energy content is 40% below regular gasoline fuel injectors needs to be exchanged to match with the higher flow needed, (or increase fuel pressure?)
I know that here in Europe there are some companies that does rebuilds to ethanol.
In all our gasoline we have a 5% mixture of ethanol but that seems to be max possible without modification.
Price for gasoline today is 65% higher than the ethanol price so theoretically it might be a good affair.
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Old 03-31-2012, 02:16 AM   #4
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Don't do it. It will ruin the fuel system and you will get little if any performance advantage in a normally aspirated engine. If you were running a turbo, then yes you could get a significant advantage. There is a euro version Saab turbo (can't remember the model) that runs on any fuel that will make much more horsepower with alcohol compared to gas.
Current car

2000 Boxster 2.7l red/black

Previous cars

1973 Opel Manta
1969(?) Fiat 850 Convertible
1979 Lancia Beta Coupe
1981 Alfa Romeo GTV 6
1985 Alfa Romeo Graduate
1985 Porsche 944
1989 Porsche 944
1981 Triumph TR7
1989 (?) Alfa Romeo Milano
1993 Saab 9000
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Old 03-31-2012, 04:43 AM   #5
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you will get about 20% less fuel mileage and no difference in performance and the fuel is only what, maybe 20 cents cheaper per gallon so the payoff is not worth it
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Old 03-31-2012, 12:31 PM   #6
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If the fuel injectors have 30% margin in them you can (I don't know)
then add a pulse width stretcher to the FI wiring harness,

We have converted a 924S NA race car to run E85. We did not notice and appreciable
increase in fuel consumption. In our case the 944 Turbo injectors flow 28% greater and we just swapped them in and fired her up.
Checked with a wego and all was good.

Butt dyno says we're doing fine on power. Smells weird -- not bad just weird.

Only issue we had was we needed to replace the fuel filter when we ran out of gas.
Gummed up from sucking up the bottom of the tank.

FWIW, we ran out of fuel because our gauges lost a ground connection
and it was coincidence the fuel gauge stopped recording properly (read 1/2 tank).

Note this was only our first race -- but 22 hours on the clock -- so far so good.

There are concerns about fuel lines, pumps and filters -- but the jury is out on this.

Last ethanol we bought was $2.99/gallon and with the Boxster's needing premium
thats > $1.00/gallon cheaper.

I've considered converting my Boxster S, but haven't done so yet.
Mostly because the Ethanol isn't conveniently available.

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Drivers: '08 Cayenne Turbo, 96 993 Çab/Tip (wife's) & '92 964 Cab
Race Cars: '75 911 RSR Clone & '99 Spec Boxster

Last edited by seningen; 03-31-2012 at 12:35 PM.
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Old 03-31-2012, 05:44 PM   #7
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Slightly different topic, but here goes
Most of the gas stations here in VA have the 10% ethanol, but a few indy stations have 100% gas. On the 10% ethanol, I get 25-26 mpg per tank highway; on the 100% gas, I'm up around 28. 10% ethanol makes the idle 100-200 rpm higher. For autocrossing, with the 10% ethanol my times are down on comparable courses and the car seems to lag a bit.
I carry a 5gal fuel can for racing and only use the 100% 93 octane. Losing by .03 sec is not fun, and I don't want to blame the fuel.
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