Bluehinder

They just started selling here for "off road use". $4.20 a gallon. Premium, unleaded.

Any advantage or disadvantage to running it in current 911's? I'm thinking of using it in my GT3 to arrive in January, or my 991 911.

Thanks.

991 3Turbo

I would skip it. Something is awry with your explanation. Is this at a service station or what? If it is a service station they are not gonna let you pull up and fill it up if its off road. Are you sure its unleaded?

I am not from Colorado, but some states(like Minnesota I believe but not Iowa) have ethanol mandates for ALL road gas, this may be the case. Make sure its unleaded. In Iowa here I always run non-ethanol gas in everything I own. Ethanol is very hard on lines and seals, etc.

Mike in CA

This from Wikipedia:

In theory, all fuel-driven vehicles have a fuel economy (measured as miles per US gallon, or liters per 100 km) that is directly proportional to the fuel's energy content.[55] In reality, there are many other variables that come into play that affect the performance of a particular fuel in a particular engine. Ethanol contains approx. 34% less energy per unit volume than gasoline, and therefore in theory, burning pure ethanol in a vehicle will result in a 34% reduction in miles per US gallon, given the same fuel economy, compared to burning pure gasoline. Since ethanol has a higher octane rating, the engine can be made more efficient by raising its compression ratio. In fact using a variable turbocharger, the compression ratio can be optimized for the fuel being used, making fuel economy almost constant for any blend.[26][27] For E10 (10% ethanol and 90% gasoline), the effect is small (~3%) when compared to conventional gasoline,[56] and even smaller (1–2%) when compared to oxygenated and reformulated blends.[57] For E85 (85% ethanol), the effect becomes significant. E85 will produce lower mileage than gasoline, and will require more frequent refueling. Actual performance may vary depending on the vehicle. Based on EPA tests for all 2006 E85 models, the average fuel economy for E85 vehicles resulted 25.56% lower than unleaded gasoline.[58] The EPA-rated mileage of current USA flex-fuel vehicles[59] should be considered when making price comparisons, but E85 is a high performance fuel, with an octane rating of about 94–96, and should be compared to premium.

Bluehinder

Didn't think I needed to give a full explanation for an answer. It's an industrial oriented station with contracts with all the heavy industry in town, garbage trucks, plows, etc. Team Petroleum, very reputable. Of course I'm certain it's unleaded. I currently run it in my tractor, snow blower, mower. They just started carrying the premium unleaded. It's very industrial, you show up with a gas can, fill your own can, go to building inside to pay. No body gives a ****. No questions asked. They carry all kinds of gas, including 110 octane racing fuel. It's not a service station.

The guys working there are very cool, beards like ZZ Top, anti govt, they don't pry.

GrantG

Hi There - I'm a local and have tons of experience with buying the regular 91 Octane swill (usually 10% Ethanol), pure gasoline (the stuff I buy is from Brad's Conoco in Lakewood), and E85.

A new 911 will definitely run better on Non-Ethanol - you'll be able to feel the difference seat of the pants...

The non-Ethanol stuff will make your car faster than the stuff with up to 10% Ethanol in it. Ethanol has less energy density than gasoline (quite a big difference). You'll also have better fuel mileage with non-Ethanol to offset some of the higher cost.

With my EVO, I can change the fuel map to run on E85 and then I can run the turbo boost to 24psi and get an extra 100hp and ft-lbs than with either gasoline mix. And it only costs $2.75 per gallon for 107 octane.

But unless you have a turbo with adjustable boost and fuel mapping, non-Ethanol stuff is best. The 91 octane stuff with Ethanol is unequivocally the worst.

Which station did you find with non-Ethanol?

frayed

As a rule ethanol is the work of the devil. I do my best to avoid it in my boats b/c ethanol has issues with stability, phase separation, fuel line damage, and can be hydrophillic.

In a car used regularly, most of those are not issues.

However, ethanol blends produce less power; in theory your ecu can adjust to take advantage of the higher quality fuel.

LexVan

I say, buy octane. 93 octane with ethanol is better than 91 octane without ethanol.

If all you can only get 91 octane, than 91 octane without ethanol would be best.

There is no more 93 ethanol free. Only 91. As far as I can tell. If they say it's 93 I'd be very suspect.

GrantG

I disagree. The amount of power lost due to the lower energy in the ethanol fuel is greater than any gain due to the 2 points of additional octane at high altitude.

The air here has so little density (>15% less than sea level) that it lowers the effective compression enough, so that there is almost no benefit to more than 91 octane in a stock GT3.

And any added ethanol reduces horsepower noticably.

Results are different with turbocharged cars with custom tuning.

But it's a moot point, since I don't think they sell 93 octane in Colorado (even with Ethanol). It's either 91, E85 (which is 107 octane), or race fuel.

Race fuel (unleaded, non-oxygenated like the 98 octane stuff below) would be best for a new GT3 (just marginally better than the non-ethanol 91, but more than double the price)...

This is what they sell at the track:

Sunoco 260 GT 100 octane unleaded street legal 3.3% oxygen, $9.46/gallon
Sunoco 260 GTX 98 octane unleaded not street legal 0.0% oxygen, $9.51/gallon
Sunoco Standard 110 octane leaded not street legal 0.0% oxygen, $9.21/gallon

Mike in CA

I'm not a fan of ethanol for a number of reasons, and I'd agree that, given a choice, non-ethanol gas is definitely preferable. The OP should buy non-ethanol if it's available and is competitively priced.

But the math suggests that the difference between non-ethanol and an approximately 10% ethanol blend isn't very significant. Ethanol contains 34% less energy per unit than gasoline. But since it makes up only around 10% at most of each blended gallon of normal gas, the overall reduction in energy content is only around 1/10th of that, or about 3%.

Maybe if the seat of one's pants is really educated it would notice, but I doubt most people could tell the difference. I realize the effect might not be exactly linear, but a 3% reduction in power would make a difference in the 0-60 time of a GT3 of about .1 of a second. Probably not noticeable in any situation on the street.

jumper5836

I have non ethnol gas available and from watching fuel consumption. I see better mileage with non ethnol fuels. I have a theory that they mandate (here in Ontario) gas to contain ethnol not to be green but so that you burn more fuel so they can collect the taxes on it.

CAlexio

You might also enjoy the brake caliper conspiracy thread found elsewhere on this forum :-)

GrantG

So, you would lose 3.4% of your hp, but that assumes perfect air/fuel mixture. However, ethanol needs to burn much richer than gas, and the ECU is not going to burn the mix perfectly since it assumes gasoline, so the loss is more than 3.4%...

Mike in CA

From what I've read, oxygenates in fuel are approaching 10%, but not in all areas, so that's why I rounded to 3%. The EPA mandates 5.6% for RFG in SoCal, for example, but refiners typically are blending more ethanol than that in some places. Given the wide use of oxygenated fuel, however, I suspect ECU's are programmed for more than one assumption re: fuel quality and are able to adapt to optimize combustion.

Bottom line, we can quibble over a few tenths of a percent one way or the other, but I still doubt that the vast majority of drivers could tell the difference on the street. That said, I blend racing fuel in my tank to get the last increment of performance when track times are important.

GrantG

Fair enough. So we're talking about 15 to 20 hp on the GT3. Porsche would charge $20k for that sort of bump

donuts

Don't forget about the fact that ethanol damages catalytic converters.