Ok so I have a 2002 24v with 275k miles on it. For upgrades I have 120 hp injectors, edge chip, fass 150 ghp fuel pump, head studs and now a bd super b special. My problem is my truck won't build more the 30 psi of boost. I was under the impression that I should be somewhere in the 40 psi department. Any tips or advice would be greatly appreciated.

 

They're are a lot of factors that go into determining appropriate boost for a specific turbo. 30 psi isn't a bad number, and obviously 30 psi with your new turbo, is much greater amount of air than your factory turbo could ever produce at 30 psi. I had the same issue with my turbo when I 1st installed it, I was running 32 psi regardless how hard I pushed it. What I learned to be by problem, was a boost leak. It's amazing how such a small leak can cause such a dramatic difference. I didn't have a new turbo to manifold gasket when the new turbo arrived so I reused my previous existing gaskets.

I discovered my leaks but spraying some water on the mating surface between the turbo and manifold. It's a good idea to check between you Intake and heater grid also. Check for bubbles. I replaced my gaskets, and on my next lap with the truck, boost levels wereally as high as 50psi :-o

If it is a waste gated model, it might be worth checking the waste gate. I believe most are set for 40 psi, but if it was purchased pre owned, someone may have adjusted it and could be messing with your numbers

 

Thank you for your response. I took your advice and sure enough I have a leak where the turbo meets the manifold. I'll let ya know how it runs when I get it fixed, thanks again for your help.

 

Bad Karma not to post results of fix.