Race Fuel Octane/Performance Question

[njk53]

Our engine has a 9:28:1 compression ratio. We have been running Sunoco 110 race fuel in our car which from an octane standpoint is overkill for our motor. We are going to try a pail or two of Sunoco 260 GTX which is a 98 octane unleaded race fuel.
Do you think there will be a noticable performance difference in our car with the different fuel?

[partsbob67]

my 5.0 mustang combo loses 5 rwhp and 5 rwt on the dyno when I put 110 in the tank. I use the 260 gtx.

[Don Anderson]

Have you tried Sunoco 112 ??

[RPM5595]

Sunoco 112 is a much better fuel than 110 in my experience. On the Dyno and on the track. It is more stable (consistent) and usually is worth a little power over 110, even on low compression engines. On another subject, Don, do you have a Facebook account? Look me up on there sometime.

[njk53]

No, we have never tried the Sunoco 112. We figured the higher the octane the worse the combustion efficiency would get with the higher octane. We bought 2 pails of Sunoco 260 GTX and if weather permits we are going to Milan for the Great Lakes Stock/Superstock event on Sunday. I will let you know how it goes. Also, we can try Sunoco 112 and compare it to the 260 GTX. Thanks for the input.

[Mike Croley]

Originally Posted by njk53

Our engine has a 9:28:1 compression ratio. We have been running Sunoco 110 race fuel in our car which from an octane standpoint is overkill for our motor. We are going to try a pail or two of Sunoco 260 GTX which is a 98 octane unleaded race fuel.
Do you think there will be a noticable performance difference in our car with the different fuel?

The Renegade HR 102 unleaded has made a difference in some low compression applications, so it's possible you might see an increase. But a very different tune up will be required to get the most out of the fuel.
A number of Stock Eliminator championships have been won using 118 octane race gas in low or relatively low compression engines. It has to do with the burn characteristics of the high octane fuel rather than the octane itself.

[ron mattson]

Burn speed and specific gravity are way
more important than the octane number!!

[Mike Croley]

Racing gasoline allows you to increase compression, timing, and RPM without detonation or pre ignition. That's accomplished with Motor Octane. So to keep your engine alive, you have to first meet it's motor octane requirements. Too much octane isn't really a problem, but too little octane will be expensive.
Burn characteristics would be the next important determining factor, and then down the list a little way would be specific gravity.

[njk53]

Well we went to Milan for the Great Lakes Stock/Super Stock event and we did run the Sunoco 260 GTX. However, we only got one good pass in due to fighting oil leak gremblins. The car ran the fastest it ever had right out of the box. We also did some chassis upgrades in the off season and our 60ft times were less than desireable. So, the jury is still out on the 260 GTX but, the engine ran pretty good so, I think we are going in the right direction.