fbirch

FWIW, there are several stations locally (NOLA area) that offer no-ethanol gasoline. In my JCWS Cooper (1.6L turbocharged engine), I average about 31 MPG with the ethanol blended stuff and about 2 MPG better with the no-ethanol stuff, with approx 70/30 City/Highway driving mix.

Mike in CA

Great point. I'm not saying I approve of gas with ethanol. Just that realistically, unless we were able to do an instantaneous back to back or timed comparison, we probably wouldn't notice just climbing into the car. Even so, I'd pay extra for non-ethanol fuel for the psychic satisfaction if nothing else. The OP is lucky he has a source for it.

I just wish I had a car in my garage right now where any of this would make a real difference.

GrantG

January is right around the corner

GrantG

With my Evo, I get 200 miles to a tank on E85 (mixed street/hwy driving) and 300 miles on non-ethanol 91 (50% improvement is not subtle). Of course the E85 costs way less and gives me 425hp and 435 ft-lbs from my little turbo 2.0L.

Bluehinder

I'm convinced. Just bought four VP fuel jugs and hoses.

JohnnyBahamas

There is a Exxon in my Tahoe neighborhood that sells it for street use. The owner stated that stations located above a certain altitude, 6500' IIRC, are allowed to sell ethanol free gas if they choose. Again, that's what the guy behind the counter stated ...and he's been selling it for years now.

It is .75 cents a gallon more expensive then premium SHELL gas though, and since I'm running a boosted V8 with power to spare at altitude I pass on it.

Summary, apparently it's legal to sell ethanol free above a certain altitude.

BC

I hadn't heard this one before. Did it also steal your dog's food? Your statement is incorrect. It makes no difference to your converter.

You are either confusing it with leaded fuel, or methanol, or hair spray.

BC

In Modern cars, if the injectors are sized appropriately, (read, not too small and at 90% already in duty cycle), then the increased ethanol in gas past the 10% would only improve the knock resistance of the fuel. Since most cars are coming out with 11:1 compression, the knock sensors are on alert at all times, and you would gain some horses that would come from no ecu retard because of the crap 91.

BC

In what car? Where is the ECU assuming? The oxygen sensor is doing its job - usually - so it will know that the stoich is slightly different.

donuts

I don't have a dog. My statement was the result of my own experiences as well as a Google search of: ethanol, catalytic and converter. It seems like popular opinion is that it damages your converter.

I wasn't confusing it with leaded fuel, or methanol, or hair spray.. Thanks

bernardbarbour

Well this is a great thread about Ethanol and I just want to throw in my .02 cents. In addition to our 2004 Carrera C4S, we have a 04 Land Rover Discovery and a late model Infiniti G35. The G35 seems to not care if I run the non ethanol stuff through it or not, but with the Porsche and the Land Rover these two do not like vegetables in their gas. The Rover has the most problem with the stuff, especially at idle you can tell. When I run the non ethanol fuel in the Porsche it idles fine, seems to have more power and I get better fuel milage. Just my .02, Cheers

ScorpionT

BC is definitely on the right track. I will add some more information.

I did a quick search to see why people are under the conclusion that ethanol damages catalysts. The single thing I see is "ethanol burns hotter than gasoline". Absolutely incorrect. Ethanol burns cooler than gasoline, hence the lower energy rating.

Its likely the 991 is designed to run on 93 octane, and its quite likely the ECU will slightly retard timing when switching 91 octane. This means there is zero performance or mileage benefit from switching to 91.

98 octane would absolutely not be best for the 991 GT3. The car was designed from the factory to run optimally on 93 octane. To take advantage of 98 octane the engine would need forced induction, higher static compression, or very advanced timing. Adding 98 octane does absolutely nothing, and in most cases would have negative effects because most (not all) higher octane fuels have slower burn rates than lower octane fuel. High octane adding power to a normal street car is a myth.

Mike in CA

+1 Because 91 octane is the only thing routinely available in California, I occasionally blend the 98 octane available at nearby Sonoma Raceway to bring the average of a tank up to 93 when I'm tracking the car. Anything above that with a stock motor is, as you point out, a waste of money and offers no benefit.

frayed

High octane adds a bit of insurance against your the car's ECU/DME from pulling timing during hard track sessions at high ambient temps. Today's anti knock systems are incredible and timing is generally pulled before any actual pre-ignition events. That said, I'm sure that at some octane level it's a point of diminishing returns.

GrantG

In my car, 2006 Mits Evo IX, the ecu assumes gasoline for stoich. I have to load a new map when changing fuel composition. The O2 sensor is only in closed loop mode when idling.