sabre81

im wondering because i think i have bad/low octane gas in my tank. Im wondering if i should run the tank to almost empty then fill it with good ol 93, or if my normal fills from half a tank will eventually filter out the bad/low octane gas.


thanks

Injuneer

Just add some higher octane fuel. The pump pulls off the bottom, and with the "recirculation" system, the contents become thoroughly mixed very quickly.

BUBBA

Why do you think you have bad/low octane fuel?

Did you fill it with low octane?

Does your car knock?

If your car doesn't knock because of low octane, just keep topping it off with high octane.

Hell, why not throw in 5 gal. of racing fuel?

If it doesn't knock, don't worry about it.

I use high octane with methanol. Some of the cheaper fuels are not worth buying because they don't have the good additives, like mentanol and although you might save on gas, you will probably get lousy mileage and shorter engine longevity in addition to lower power. JMHO

sabre81

well i logged a drive with freescan and got knock retard up to almost 13 deg. so i think between the new better gas and the lt4 km i put i, it has been running better.

rpm4lalo

I remember looking through LT1 Edit and seeing a "low octane retard"
The pcm would retard the timing when a low octane gas caused knock.
I have mine set to something like 8 degrees as the max the pcm will retard the timing if i accidently put in something lower than 93 octane.