Anyone know what the stock turbo pressure are for a 2001. Ive got a boost gauge installed on the air horn and it really stays lo 3-5 psi till about 2200 rpm then it picks up to about 15 psi. is this normal?

 

im getting 31psi before gate opens on a 02 hy35. turbo is not modded at all. and boost pressures dont lag it ramps up evenly with rpm's. Is it the same turbo from your cummins build post. If thats the case you said that you think that motor was ran with out oil well that means the turbo was as well. Just a thought

 

I replace the original turbo with another good used one which I installed a bearing and seal kit. the end play and side play toloances are within spec. I think this is an HX version I have the 6-spd manual.
So what you are telling me is the turbo should gradually spool up from idle.

 

yes mine increases as the rpm's go up and down in sync. yes the hx is for manual and hy is for auto in fact the hx is a better turbo than hy. the reason for the difference is the stock trannys cant handle any power

 

yeah you should be seeing more than that, boost leak perhaps?

 

boost leak, wrong exhaust manifold gasket ( I learned that one the hard way) you should be hitting about 20+- before your waste gate pops I am hitting 24 with a fresh rebuild

 

If you check out this page:
2001 ISB engine specs
It list A LOT of the info required for the Cummins engines in your trucks. 20.8PSI for 5 speeds and Autos, 26 PSI for 6 speeds.

 

As said before, check for leaks. You should be around 25-30psi stock

 

As long as it has the fueling to push it there

With stock fueling if you read further down the page, it says typical WOT boost on a HO is around 20psi. Now if you had it tuned I could see the 25-30psi. But to the OP, I would think you should see more than 15psi.

 

What is your exhaust housing diameter. It is casted in your turbo on the exhaust side. I had a 18 cm on my truck stock and did the same thing. Went to a 12 cm and spools up much faster. The bigger the housing the more exhaust gases have to pass through to spool up turbo.