100 Octane

[haasman]

I filled-up at a Shell station a couple of nights ago and they were selling 100 octane fuel for ..... $4.29 a gallon!

Reminds me of the old Sunoco days back east.

Haasman

WoW....That's odd!

Why are they selling extreme high octain gas? Is this a new trend starting to happen. What consumer group are they appealing to?

Till now, the highest octain available had been 93 with 89 and 87 following, here on the east coast.

I'm old enough to remeber the days when you could buy 100 plus octain, Amaco white-gas, that was necessary for the big Cadillacs, Lincolns, muscle cars, Corvettes etc.

They must be trying to appeal to the big SUV audiance and ultra high horse power performance vehicles now available... BB

[yal]

Here in New York the highest octane is Sunoco 94.
Are there any cars out there requiring 100? Maybe a Lambo or Ferrari?

[hihosilver]

I live in az. and we have 100 on the pump mostly for the high powered boats running the colorado river @ $2.69 a gal. been wanting to try it in my 300e but it is a low lead and didnt know if it would hurt the converter, my harley loves it

[deanyel]

It's a niche market - been available like that on a limited basis for many years. It's for hot-rodders, street racers, and people who want their car to run well while for sale. At those prices it's going to remain a niche market as far as I'm concerned.

[Jeff Hartmann]

I was trying to remember, was 109 the highest you could select at Sunoco when they had those dial your octane pumps?

I remember a customer in the mid 60's at Caldwell Airport( now Essex County) NJ that bought either 100/130 or 115/145 octane aviation fuel for a big block ford that he raced.

[Duke2.6]

Some Unocal stations in CA sell 100 octane unleaded race gas from pumps, but, I didn't know that a similar fuel was available from Shell.

The current 100 PON is equivalent to a 104 to 105 RON fuel from the sixties, so it would be okay for an L-88 Corvette, which had a CR of 12.5:1 and required a minimum of 103 RON.

Duke

[nglitz]

Catalytic converters & O2 sensors need NO-lead fuel. "Low" lead will kill 'em.

[Brad E430]

It might be enriched ethanol blend.
Here in Iowa and Minnesota, some stations sell 100+ octane that is 80-90% ethanol.
And it’s usually as cheap as regular gas - $1.80/gal.
Just remember that octane is not a rating of power, rather it’s a rating of the ability to burn. I.e. high number = easier to burn.
Also, ethanol has a lower power by volume factor than plain gas. Your engine will not miss but you will get less miles per gal.
FYI, diesel has the highest of common fuels: approx 160k btu/cc vs 140k btu/cc for gas.

[DaveL]

FWIW - I sell hi performance gas (110 Octane Sunoco, $5/gal), and build race motors (for motorcycles).

High octane fuel is only appropriate with very hi compression motors - if you put it into an engine which runs well on 91 Oct pump gas, it won't help anything (maybe slightly lower cyl head temps), and will most probably result in a decrease in power.

Most engines make the most power with the LOWEST octane which will burn clean (no pinging, knocking).

I have won lots of races (literally 100s) running 89oct pump gas in "factory stock" motors.

-David

ps - Yes, any "leaded" gas (low-lead included) will ruin cat converts.

[DaveL]

Also, I imagine that if you tried to buy gas out of that pump (100oct Race Fuel) then they would tell you it has to go into a container (or a boat), and that you cannot pump it direct into your car.

There was a run of "exotic fuels" a few years ago in the motorcycle race circuits and the popular stuff was ELF. It was rated at about 105oct, cost about $40/gal, but it was something other than "gasoline", (there is a test for specific gravity,and if the "fuel" passes, you can run), and if you got near an open container it made you feel really sick, BUT it resulted in a few horsepower (in built motors - stock motors just ran "crisper", possibly better throttle response but no real increase in power).

-David

[Duke2.6]

Jeez - the current EPA limit on ethanol concentration (by volume) for pump gasoline is 10 percent, so any oxygenated gasoline dispensed from a gas station as motor fuel for on-road vehicles is no less than 90 percent gasoline. An automtive engine designed for gasoline or "gasohol" with a small quantity of ethanol will not operate on a high concentration of ethanol due to the substantially different A/F ratio, which would require considerably higher mass/volume flow of fuel.

Octane rating is a measure of resistance to detonation. That's it! It doesn't burn "slower" in the absence of detonation. If an engine operates without detonation on a given octane, then additional octane DOES NOTHING!!!

Ethanol is an octane enhancer, but has less energy density, so base stock gasoline oxygenated with ethanol has lower octane than a base stock not intended for oxygenate addition. Ethanol brings a base stock intended for oxygenation up to the pump posted octane. Also, ten percent ethanol reduces the energy content by about 3 percent so fuel consumption is increased by about a like amount.

Duke

[MTI]

In AZ I can understand slightly higher octane . . . it's actually the heat and humidity levels that can affect engine performance.