ok i have a 3.12 pulley going through an intercooler with 2.5" piping and an HKS race bypass...... i changed my belt and picked up a few psi but right now im only at 6-7. I dont think it would be a leak because my car would act really bad if air was leaking out.... so what could it be?? do i need a power pipe to get the right boost (im using the stock vortech power pipe) this pulley should be giving me really dissapointed [:@]someone help..

 

bump...[&:]

 

6-7psi with a 3.12 pulley is about right. i run a 3" pulley and get about 9psi at 5k. also, the better your engine flows, the lower the boost will be for a given pulley size

 

Yea I am only getting 5 but I think I have some belt slip and I just upgraded my Throttle body to a 75mm setup. It tachs out at 5 real quick and just sits there. Dont know yet still diagnosing it.

 

man it's been a while and you're still having a problem. you say you don't think its leaking...but did you do a leak down test. you can buy one or make one yourself. i used a pvc cap and just tapped in a fitting. use a coupler to fix it to the sc air inlet. hook up a compressor and listen for leaks. a stethescope (sp) will make the hissing obvious if you have one. check all couplers, tb gaskets, intake, and all fuel injectors. then you can say you KNOW it isn't leaking

 

actually the other problem i had a while ago was belt slip, i fixed that right up and gained 2-3 psi.....this is something new after i changed out my vortech bypass for a race bypass hoping to pick up a few psi, i have checked for leaks i have not done that test but i have gone through every one of the pipes and checked for leaks, they are none existant, but one thing i do think would help is going through all the pipes again and trying to take out as many bends as possible... that should out a little, and then i have a power pipe i get made by the end ofthe week....i gotta have at least 8-10 psi to finally get my re-tune.

 

i see. did you tighten the spring in the bypass valve? it could be leaking only under boost. who makes your intercooler. is it tube/fin or bar/plate? do you know the pressure drop? what size piping are you using for your intercooler? let us know how it goes