Newbie Question about racegas

[boostineklipz]

When putting in race gas, will the higher octane make the car run richer or does the higher octane just make the chance of knocking less?

So when boosting 20+ psi, should I lean out anything on the S-AFC or just leave alone?

 

[taylorspl]

I'm an idiot.

 

[NJR Racing]

once you crank up the boost to 21 psi your leaning it out already because your forcing more air in the motor....i would turn up the boost and leave it alone at first.....if you have a logger then you can see if your rich......

 

[ahains]

Higher octane will make your car run richer?
How ya figure?

"Rich" refers to the air / fuel ratio. The ECU, fuel pump, fuel lines, and injectors do not know you have put in high octane fuel, so I can't see why this ratio would change.

The ECU doesn't know anything about the fuel, it only knows if the intersection of the operating parameters of the engine are producing knock.

Maybe I'm missing something, but I think your A/F ratio should remain unchanged.

I guess one point is that you have a different ratio of gasoline to additives, so the a/f of stoich has changed. So in a way, I guess you could call that richer or leaner. Actually A/F refers to the ratio of the mass of air and fuel, and racing fuel has a different specific gravity so the A/F does change some minor amount.

But the point of your question is probably "should I lean out somewhat when running race gas", and the answer to that is yes

Cheers,
Adrian

 

[boostineklipz]

Thanks for the responses. I am going to leave it alone the first run and see what the pocketlogger tells me and go from there.


On a side note, this is my 1000th post

 

[kpt4321]

That sucks, 1000 posts and you are still a newbie?

Race gas does NOT make the mixture richer. It's still the same amount of fuel.

However, race gas lets you lean the motor out, which will also adv ance your timing if you use a piggyback fuel computer like an AFC.

...Kyle T.

 

[boostineklipz]

I think i will always be a newbie. Well this is my first race gas experience.

I am using a AFC. I finally got the car where its starting at 9 degrees WOT at full boost and ending around 18 degrees.

So the race gas will advance the timing due to the higher octane. I will jsut play with the pocketlogger and take away 1 or 2% until its back to a nice timing curve.

 

[90AWDTalon]

It will also allow you to run more boost before knocking.

 

[Defiant]

Higher octane refers only to knock resistance (the opposite is cetane, which you want in diesels. It's also what un-du adhesive remover is, and maybe Goo-Gone.). If anything, it would make your mixture leaner due to a more complete additive package, but only on a molecular level. Higer knock resistance = earlier possible timing. Also due to these additives, you'll have more deposits, but again not measureable over the short-term.

 

[boostineklipz]

Originally posted by Defiant
Higher octane refers only to knock resistance (the opposite is cetane, which you want in diesels. It's also what un-du adhesive remover is, and maybe Goo-Gone.). If anything, it would make your mixture leaner due to a more complete additive package, but only on a molecular level. Higer knock resistance = earlier possible timing. Also due to these additives, you'll have more deposits, but again not measureable over the short-term.

Thats good stuff. This has been a very informative thread. Thanks guys.

It will also allow you to run more boost before knocking.

Thanks captain obvious