Why will Procharger P1SC not take timing?

[Perry2]

Okay this is on an LS1 but the fundamentals should be the same except boost right? I have the older twin i/c setup which I know is less efficient but it was only managing 13 degrees timing at 6000rpm and 5 psi. With the boost up over 7 psi I need to run 11.5 degrees to avoid knock. I have a good 94 Octane fuel, new plugs and wires of the standard type for P1SC, and have run Seafoam through it in case of carbon but it is only a 25k engine. AFRs are good all the way up. What might be going on?
I haven't check IATs yet. Has anyone ever had issues with piping leaks? The knock is logged on HPTuners so is not false. Any ideas?

[RocketSled]

The clue is your comment about the problem occuring at high RPM. At a guess, I'd say you don't have enough fuel pressure. If you're using the LS1 stock fuel pump, it barely has the b*lls for 5 PSI, never mind 7, when you got WOT at red line. As boost increases, pressure drops and the system leans out because the pump can't push enough fuel. AFRs may look "good" superfiecially, because they're lean, but at high boost to keep from pinging you actually want to be rich.

If I'm right, you're going to have to do what I'm planning to do for my Vortech setup (which does have an aftermarket high volume pump but is still marginal at WOT and high RPM), which is to run a return line and put a boost-referenced regulator at the front of the car.

[PuJu Z]

Originally Posted by RocketSled

The clue is your comment about the problem occuring at high RPM. At a guess, I'd say you don't have enough fuel pressure. If you're using the LS1 stock fuel pump, it barely has the b*lls for 5 PSI, never mind 7, when you got WOT at red line. As boost increases, pressure drops and the system leans out because the pump can't push enough fuel. AFRs may look "good" superfiecially, because they're lean, but at high boost to keep from pinging you actually want to be rich.

If I'm right, you're going to have to do what I'm planning to do for my Vortech setup (which does have an aftermarket high volume pump but is still marginal at WOT and high RPM), which is to run a return line and put a boost-referenced regulator at the front of the car.

I agree. I was having the same problem on my z before i installed the boost-a-pump. Since my fuel pressure has been up, I haven't had the surging or breaking up that I had before. I added the boost-a-pump and upgraded my injectors.