20-25 stock

better to get an s300 turbo with a better wastegate and better flowing exhaust housing. There is no reason to turn up an hx35 to over 32psi as the air cannot get out easily. You end up with a pressurized box because the WG on the hx35 sucks (only wastgates 3 cylinders) and then it is further blocked by the back plate before it goes into the downpipe.

they say no more than 45psi with stock turbo:scare2:

I'm supposed to be doing the head gasket this weekend (if I can find one), I have a thread right now going wondering if Felpro gaskets are acceptable substitutes for Cummins ones if you can't get OEM.. I am running the stock turbo at about 30-35 PSI, though I usually have to back my foot out of it if I have a heavy trailer and big hills.. if I'm not towing over 4 ton it's not a problem though. I am really looking for a SuperB turbo though so I can comfortably put 40PSI into it without it coming apart