100 Octane Fuel

[Jonathan]

A few question from a person that is automotively challenged:

1) Cost aside, does 100 octane fuel offer up any performance benefit over 91 octane in spirited everyday driving?

2) Would it cause any harm, or reduce the overall benefit (if any, see #1) if it was mixed with 91 in limited quantities?

Anyway, just curious, I noticed a local pump has 100 octane ($4.29/gal), I am not really thinking about getting any, just made me curious and figured someone here could answer it pretty easily.

JS

 

[BLACKL@BEL]

I run full tanks of 100 octane from 76 and it doesn't harm anything (at least to my knowledge). I haven't noticed any benefits with street driving (no performance gain) as opposed to regular 91 octane fuel. But I did notice that the regular smell from the exhaust dissappears when I use 100 octane.

 

[Tobal]

I tried 110 octane on the drag strips...didn't really notice any performance gains or benefits using higher rating gas.

 

[Carguy!]

A few question from a person that is automotively challenged:

1) Cost aside, does 100 octane fuel offer up any performance benefit over 91 octane in spirited everyday driving?

2) Would it cause any harm, or reduce the overall benefit (if any, see #1) if it was mixed with 91 in limited quantities?

Anyway, just curious, I noticed a local pump has 100 octane ($4.29/gal), I am not really thinking about getting any, just made me curious and figured someone here could answer it pretty easily.

JS

100 Octane fuel allows the timing to be advanced without getting detonation. If your car is stock you will not notice any benifit from using the 100 Octane fuel. There is a knock sensor that will retard the timing if lower octane is used less than 91, but if a good quality 91 octane or higher fuel is used in a stock car you will not have any retarding of the timing and the car will produce as much horsepower as with a higher octane.

As long as the higher octane racing fuel doesn't contain lead you shouldn't have any problems mixing it with other fuel but as stated above you won't get any benefit so why do it?

Now if you are running higher compression pistons, have your timing advanced or are running forced induction at higher boost levels you can see huge improvements in performance using racing fuel.

I have a car that allows you to set a value between 1 & 6 and you can only use 4,5 & 6 with racing fuel or you can get detonation and burn down your engine. I get about 150hp difference between setting 1 and setting 6.

Good Luck!

 

[nsxtasy]

As another data point, I have tried 100 to 105 octane unleaded race fuel in my stock NSX and did not notice any difference at the track or on the street.

Carguy!'s response is more comprehensive and informative, of course, but this supports what he says about the stock drivetrain.