Is the log wrong or the MAP scaled wrong or am I missing something? The scan showed a max of 8psi. Or was that a low boost pull?

Just curious is all, though after reading the rest of this I tend to agree it needs more turbo and less rpm if running just LS6 springs.

 

One pressure sensor parameter is screwy on this log, the 2 bar sensor is the correct one.

Do you know of people having issues with ls6 springs and boost?

 

At 13-15lbs of boost, you just might be pushing past the valve springs. Before upgrading the turbo, I'd definitely swap something with better seat pressure in there. The PAC1218 springs seem to be the go-to for budget builds.

 

So are you implying on the compression stroke the manifold pressure is opening the intake valves and bleeding cylinder pressure into the manifold?

 

I'm implying that the pressurized intake air is pushing its way past the valves (into cylinders) that would otherwise be closed.

 

If anything you would have more of an issue on the exhaust side than intake side.

 

so with a 3 inch dump this issue has almost gone away, I think I have just pushed the problem further up.

Thanks for the help guys!

Also Atomic I'm starting a thread in the fuel system page that I would love to hear your input on. its sensor related.

 

Valve springs get blamed far more often than they should. This is one of those times.