I just put a 9# pulley on my powerdyne and it is only showing around 5psi on the vac/boost guage.. it is definitaly boosting higher than the little over 1psi that the 4.5# was doing.. I replaced the belts and the tensioner pulley also...The car has gained ALOT more power and runs better in general.. not as much backfiring and the air/fuel guage is more in the stoich zone when idleing.. where as before it seemed to be running a little rich.... Is it better for the engine to be only boosting around 5psi or is their something wrong.. the car has an agressive cam,intake,high flow exhaust,headers,bored slightly,btm msd ignition,and a few other goodies but no lower end work... Is this a SAFE set up.. It is NOT my daily driver but I do drive it on the weekends often.. If I don't boost high all the time and drive it descent do you think this set up will last ...Engine and trans only have around 25k on the rebuild and their is very little blow by and no unusual noises.. thanks for any comments or advice..

 

If your cam is too big it may be losing boost during the overlap phase.

 

If you're using a standard O2 sensor with the A/F ratio guage, it's pretty much useless. Get a wideband O2 sensor (or go to a dyno with one) and see what your A/F ratio really is. That will help you find out whether your car is running safe.

 

i agree, get that thing tuned on a dyno. better safe than sorry. as far as boost numbers i kinda look at them like stall converter numbers. when they say 9# pulley i say what engine with what heads at what rpm. example my p1sc was 8# setup and on my stock motor thats what i got at WOT @6000rpm. the same blower on my next motor maybe 2# same conditions.