i have a gm stage 1, 3" pulley, and smaller belt.
after a firm 1-2 shift it wont let me boost past 13 psi for some reason. i even tried doing the stupid boost bypass mod and it still wont let me. however, if i shift easy into 2nd at a lower rpm and just roll on the throttle, the boost will go to 15 like it should.

is the pcm pulling timing because the engine movement is triggering false knock during shifting? anyone have any ideas?

 

Is your rev limiter set at 7k?? Also take that boost bypass mod off before you blow something up! What year is your car?

 

You can't blow anything up with the bpv disconnected and a 3" pulley.What is your altitude?
When you disconnected the bpv did you pull the bottom hose off and plug it?With that disconnected the pcm has no way of limiting boost.So timing will have no affect on it.Is it a stage II belt?

 

i pulled the hose off teh back of the solenoid and plugged it as per the instructions in the sticky FAQ. yes its a stg 2 belt, and my altitude is 1500'

its an '06 and yes my limiter is 7000rpm

i narrowed the gap on my spark plugs down from .042 to .035 and it seems to not be doing it as much.