Real Knock or Phantom Knock?

[caffeinetripp]

It's set at 20. But honestly, I RARELY hit 20. Work's a mile away and it's 35 MPH the whole way. I am going to dial it down quite a bit though since I just noticed it hitting 20. The guy that owned it previously had it 'set' at 14, but since the boost leak got fixed, the actual boost is going to the motor instead of the 14 that should be.
It'll take some more fine tuning of course, but since I haven't the slightest on fine tuning I'll be skipping it until MAP can take care of it.
Looks like I will be hitting up the BP from now on then. lol Or Holiday. One of the two...but SA is so damn close.
Any reason SA gas is bad? Figures? Numbers? Pie charts?