Running race gas
 

Just wanted to see who runs race gas at the track?

Yes, you must be tuned for it to be useful.

FML...yes you have to be tuned for race gas. octane is solely resistance to detonation. you will be slower with race gas if you are not tuned for it

I agree that it won't help you at all but I can't see how you would be slower with a higher octane gas.

the higher the octane, the slower the flame front so the burn is less efficient without proper tuning. that = less power. :lock:

It burns slower, you are not getting the optimum combustion of the fuel if you're not tuned for it. Slower burn means it takes longer for the potential energy to be released, reducing the amount of peak kinetic energy produced instead you're just prolonging the burn time. Same amount of kinetic energy produced, just over longer period of time.
Edit:this is not exactly correct but something along these lines. It's an easy way of thinking of it

That is what I found also but I blend in 100 or 104 with our crappy 91 oct out here and bump it up to about 93-95 but using straight 100 or higher doesn't gain anything w/o being tuned for it a lot of the evos/sti's have two tunes and load a 100 oct or e85 tune up for track days. As does the gm stage 3 tune has the high octane mode for 100.

Gas blend calculator

http://ranney.com/mjr/fuel_blend.html

Call me stupid. On second thought call me uninformed/misinformed on the octane discussion. There are some people here that seem to actually know something about octane. Our ECM corrects ign. timing to compensate/protect for lower than recommended octane levels, by way of the knock sensors. Correct? Is there a programmed ign advance limit in the ECM that prevents the timing from going beyond a certain point in ANY event? If so what is that point? And could that point be removed, or adjusted, to continue advancing the ign timing depending on available octane/knock?

Like I said. I'm not the sharpest tool in the shed. Just sharp enough to get the ax stuck 1/2 way through the log.

i am tuned for 100 octane cause of meth, when i go into boost with my meth kit off running cam 2 110 octane it's slower and runs like shit. if you tune a few degrees less than the octane calls for just to be safe, it'll get you tons of free hp. just keep in mind most race gas contains lead and will beat up your o2 sensors and almost immediately wreck your cat.

how your ECM is set-up is that it has a "High Octane spark table" and a "Low Octane spark table" it normally runs on your high octane table which has a set amount of ignition timing. if your car knocks for a significant amount of time, it will revert back to the low octane table which has less ignition timing. the only way to advance your ignition timing would be through a tune

So you're saying there are TWO seperate tables with TWO preset advance limits and the knock sensors toggle between the two? I would have thought the advance would be a variable dictated by knock but with a fixed limit. Very interesting. Thanks for helping me sort this out.

That makes sense, thanks guys. :cssNET:

i've used 100octane
not tuned for it
i thought i felt a very noticeable difference

maybe it was just me haha

Dont use leaded what ever you do. And no its not an opinion, I have a few times and toasted an O2 sensor.

IIRC, trifecta offers a tune that can be switched to allow use of higher octane fuels when desired.

This is true, but say bye bye to your cat and o2 sensors

Unless you use unleaded race gas which I know is available just hard to find.

I wonder if Trifecta is capable of running their dual mode tune in a way where you can switch between 93 pump gas and E85. E85's effective octane rating is pretty good.

So, with all this being said... Say you were to put more than you wanted of 100 Oct mixed with your 91 Oct, ran your car with no cooling mods in 90-100 deg track weather, and increased your elevation by 1500+/- feet, would you loose about 3-4 MPH in your trap speed un-tuned?
Cause that's what probably happened to me...

I run it all the time lol.

That's basically how GM set the new Camaro V6 engine to operate.

It knocks a lot. They basically cranked up the timing advance and are depending on the ECU to detect and retard the timing back down as needed.

It says something about GM's tuning demeanor, but also says something about how far ECUs have come since GM's willing to back that strategy with a warranty.