While using higher octane fuel gives an extra margin of safety during tuning, I have heard conflicting statements that it won't give u an accurate reading at the second O2 sensor for the dataloggit (in the case of the PFC) when adjusting for A/F ratios for pump gas use.

Any thoughts?

 

Race gas will change your AFR's marginally. Their specific gravity and oxygen content all vary and are normally different than pump fuel. Your best bet is to run some decent unleaded race fuel to get your tune close (and stay safe). After getting close fine tune it with your normal pump fuel in the tank.

 

You should tune with whatever you plan on using. i.e. don't run/use anything you don't plan on using when driving (if you are going to run pump gas, tune on pump gas... if you are going to tune with race spark plugs, keep using race spark plugs)...

 

i agree, Alain remember mine is tunned for 100 octane and get bad knock at 7 psi running 91, I need to have my maps changed to run 91 octane@ 11psi so i dont blow again

 

If my only choice for pump gas was 91 octane, i would always run at least some race fuel in the tank for safety purposes. Maybe run some toluene or something.

Adam

 

I can get 100 octane which i think my jdm pfc is ment for out of the box but it cost around $5 a gallon or more now. I would rather have my base maps tunned to run good old crapy CA 91