Friends, Thought I would share my good news/bad news finding with all. I was surprised to see that no one had posted on this yet. After reading about the difference in energy produced between the same quantities of ethanol and gasoline, I have wondered what kind of a difference would it make to put 100% gasoline in my 98 xk8. I live in the NY, NJ, Conn tri-state area, all of the gasoline at pumps contains "10%" ethanol. Well I found the Sunoco website that provides locations of "racing" gas. One is nearby, the gasoline has no ethanol and is rather high octane. I visited and it turns out they only dispense it into containers. Well I couldn't resist so I bought it on line. I was surprised that UPS ships it for them. I let my gasoline level drop to 3 gallons and added 10 gallons of their fuel. Well as I mentioned earlier this is good news/bad news. The good news is yes, it makes a noticable difference, unfortunately that's the bad news too The stuff costs $10 per gallon! The difference was in continuity, driveability, and overall smoothness. I realize the % change in horsepower moving from 10% ethanol, these findings made me wonder 2 things, are they putting more than 10% ethanol in? Is my car adjusting, without my knowledge, for some kind of detonation that is obliterated by this higher than needed octane gasoline (100 octane). I know if I were reading this, I'd be wondering about the good old placeboo efect. I was aware of this, believe me even my passenger saw a difference. I think it was most pronounced during wide open throttle. The sound of the engine at higher rpm was different, there is a feeling of (how do I say?) just smooth power.

Well I hope you get to enjoy this sometime too. I'm no where near rich enough to use $10 per gallon gasoline much, but wow it was a blast.

John

For more normal pricing, look around your local Shell stations for V-POWER premium.

Look carefully at the sign posted on the pump. In most markets it is ethanol free, but you need to confirm at the pump.

I woud worry race fuel didn't have additives/detergents. In any case on an unmodified engine in closed loop operation 100% gasoline *shouldn't* change power (assuming equal octane and an identical tune) but *should* result in better fuel economy.

It is true that 100% gasoline has more energy content per unit volume but it is the amount of air the engine breathes which determines the HP. The appropriate amount of fuel is added to combust that volume air. In closed loop operation with E10 your fuel injecors will operate at a higher duty cycle compared to 100% gasoline. This means you will burn more fuel but you will still convert the same mass of O2 into CO2 and H2O and will still have the same power.

If you increase octane you can tune to run leaner and/or advance ignition timing and that will make more power, but that is true whether using E10, E85 or 100% gas as long as you are talking equivalent octane levels.

That said alcohol has a higher octane than gasoline in general. In the U.S. most premium gasoline is 91-93 octane depending on location, while E85 is between 95-105 octane. Some drag racers prefer alcohol (including methanol) or E85 because of the higher octane compared to most gasoline.

A 300% increase in price for a 3% energy boost doesn't sound like good economics to me.

I've been meaning to try this as well. Sunoco has a gas station offering 100 octane race fuel about 10 minutes from where mom lives. I usually fill up with 91 octane "premium" although, within the last month, one of the gas companies has started supplying all of their stations with 93 octane gas instead of the 91 octane gas for premium. The reason I haven't tried sunoco's is money, and I still haven't had a refill with 93 to tell if 2 octane is even noticeable.

I wouldn't be surprised if Puma gas is just calculating their octane rating differently as a marketing ploy.

In 1984 I bought a Mazda RX7 and at the time Sunoco sold a 94.5 octane gas. I noticed that when I used this high octane I noticed an improvement is gas mileage but really did not see an actual performance improvement. With my XKR, I always use 93 octane and so have seen no performance improvement but I do get better gas mileage when I use Valero gas, which contains no alcohol. Just my 2 cents.


Mark

We get 89 pure gas here on Maui, would this be acceptable to run instead of the 91 E–15 premium they sell?

You sure it's E15 and not E10?

E10/15 refers to the ethanol (10% or 15%). The difference between 89 octane and 91 octane are the additives to suppress pre-detonation. You can use the 89 octane but the engine sensors will sense the pre-detonations (knocking) and compensate by adjusting the timing accordingly, causing you to loose power. However, you may get better gas mileage because gas has more energy per unit volume that alcohol. I've never compared gas mileage between different octane fuel.


Mark

To me this is all greek but I'm suprised about the numbers.
The worst fuel we can buy in Sweden is 95. Then we have 98 as premium and Shell also sell 100 as V-Power.
But the 95 is 14:- (~$2.2) for one liter (0.26USG) of the stuff.

eu98 = us93

The octane number is calculated differently in Europe and the US. European 95 equals US 91, and European 98 equals US 93.

..and it is pretty pricey stuff here in Norway too; 7-8 dollars per gallon for regular.

That's correct. Canada and US rate gasoline on the Anti Knock Index (AKI) scale. The rest of the world uses the Research Octane Number (RON) scale. We switched over in the mid 1970s for some long forgotten reasons.

Usually Jaguar specifies RON octane requirements in the owners manual with most cars needing 95. More than one owner here has panicked trying to find 95 .


The ethanol content is another story entirely.

There is a Sunoco station in town with this on tap at the pump: Sunoco Race Fuels | 260 GT

I will have to see what the price is later today and report back... $9.99 per gallon!