I have a 98.5 24v ISB with a holset hx35w turbo and I use to get around 15 psi I took the silencer ring out and was pushing 15 then it came down to 10 and cant get any more than that there's alittle shaft play but not very much. I think the waste gate could be stuck open but im not really sure just looking for some help

 

How's your fuel pressure? You need fuel to make boost, no fuel = no boost.

And you should have been running quite a bit more than 15 psi. It's entirely possible that your wastegate is stuck open, but knowing you've got a 24 valve I'd verify your fuel pressure ASAP before you smoke your injection pump, if it's not too late.

I regularly hit 35psi, where my wastegate is set. When my diaphragm ruptured and the wastegate didn't open, I hit about 55.

 

I have a new vp44 and the airdog2 100gph and I have it set to 15psi

 

But what does a gauge say?

A bad overflow valve would cause lower pressure. Or a bad airdog.

 

Wouldn't you be concerned about overboost shortening the life of your turbo? Too high of boost means turbo is spinning too fast. I say this not being familiar with capability of turbos on cummins. I'd like to keep my turbo at or below 30 psi.

 

Supposedly 35 is about the top of the turb's efficiency range. 30 is safer, no doubt