Here is a general question...

When do you know you have run out of room with pump gas and need to move to race gas?

Does your A/F ratio just not decrease (richer) as you keep adding fuel???

I have a wideband O2 meter, is this something you can see on it while tuning?

Thanks in advance.

Mike

 

if your running lean...you should see it with your lambda probe with a gauge.most people run race gas if they are running high boost,high compression so the motor doesnt detonate,and cause its a slower burning fuel,it should be tune seperatly for race gas.
if your setup is properly done,you shouldnt need race gas unless your running high boost or gonna race it ,it should handle 15psi with normal fuel easy.If your detonating,and thats why you wanna use race gas,it will help,but youve got a problem somewhere else that should be looked at..like,intercooler size,aftermarket ECU(tuned properly),injector sizing...ect.

 

You need race gas when you want to run higher boost than what pump gas can stand without knocking.

As you increase boost, you'll need to go to lower and lower A/F ratios to prevent knocking. At some point lowering A/F ratios doesn't help and you need higher octane to prevent knocking.

If you have stock turbos a conservative number is 13-14 psi for pump gas- 13psi is what M2 uses in their upgraded ECU. With upgraded twins or a single turbo 15psi should be ok. It also depends on if you are looking for a road-racing level of safety, or street or drag racing, in which case you might be able to go higher. I don't know what kind of boost levels are safe there.