Wow, alo of Newb answer here.

You can buy an aftermarket knock sensor that functions as a guage to tell you when and how bad you detonating.

Running to much fuel can cause problems, from melting pistons, if you have ALOT, to washing you Cylinder wall if you have ALOT, or just plain running like crap, killing our enviroment and doing nothing to good for your performance.

On a basic boosted car running 5-10psi, your ear and general feeling should be enough.

 

I like the JS safeguard.

This thing is awesome.

just like a BTM, you can program some retard per boost like 0.8/psi and make it start only at such psi but that's nothing compared to the main feature of that marvel:

hooked up to a knock sensor (stock or aftermarket), the J&S is able to calculate in WHICH cylinder(S) the knock is ocurring and automatically retards the timing of EACH cylinder individually, just enough to make the knock disapear and then, it tells you in real time how much retard is necessary, on a per cylinder basis, to save your *** from deto. Interresting, since deto is a chain process, it takes less retard to avoid it than to stop it once it has begun.

So if the lights come on the J&S gauge, you simply add some more retard per psi to avoid the J&S saving your life.
as a result you are running your engine on the edge of detonation, no HP or fuel economy sacrified for a blindly established safety margin of timing retard.

 

yes i know im running on the rich side and adding more gas is more of a percoshin to prevent blowing your head gasket then knocking but it still helps