you ahve to take rpm into consideration...stock ap1 redline prob around 9 and change but cut down on the variables figure out what redline you want etc...

 

I agree completely with that methodology.

My Vortech kit is hitting 9.1 psi at 9100 rpms with a 4.5" pulley.

 

Somewhere around 12 to 16 psi.

 

I have a 3.875" pulley for my comptech, i make 9.2psi at 9000rpms.

 

sorry to bring this back from the dead

so in my case i'm running a vortech kit on a ap1 stock block, if i want to run 9lbs should i look into getting a 3.8 pulley or a 4 pulley?

I've been tuned on a aem ems and the tuner said i'm at 6psi.

if you can refer me as to where to purchase one i'd appreciate that too.

 

It's mainly dependent on engine rpm and belt tightness. At what rpm are you looking to hit 9psi at? On my setup I hit 9psi at 9000rpm on a 4.5" pulley.

 

sorry for the newb question but i'm guessing 4.5'' is the standard pulley?

i'm expecting to hit 9lbs at 9000rpm also i'm expecting this at the tightest point as far as the belt's concerned

 

4.5" is the standard pulley on AP2 kits. AP1 kits come with a 5.0" pulley.

I order my pullies directly from ASP Racing. They do excellent machine work and can anodize the pulley in any color for around $102 shipped.

 

being that i'm not planning on any work to be done to the motor right now do you think i should just purchase a 4.5'' and play it safe? I have all the supporting mods, 750 injectors, aem ems, upgraded fuel pump.

i'm guessing the belt's included in that price from ASP racing?