i added 30psi to the bottom of my wastegate and it still overboosted. So redesign time..

 

The more efficient the turbo is the more boost you will have with same leak, or waste gate. A 38mm is really too small for a 6.0L/76mm with good flowing turbo. With my Tc76 I could get down to 10-12 psi with my 38mm turbosmart. With gt76/94 14psi is lowest, and S480/92 16 is lowest. Like rick said a lighter spring might help some. When I run the 10psi spring my low boost becomes 20psi with the s480. To get 16psi I run the 6psi spring.

 

I had this same issue. 7675 turbo 40mm jgs kb racing kit with a 7lb spring i could make any boost I wanted literally... I even took the spring out and it still make boost. I eventually took the crossover and dp off and sent it back to kyle and he installed me a tial 60mm and it checks up fine now.

 

check for boost leaks.
tune for 16psi

 

Its hitting 16 psi in the intake manifold. Gotta get more fuel to it or spend 500 bucks right before Christmas! ! UGGGG! !!

 

i can do 25psi + on mine

 

With the 60mm how low can you get the boost?

 

I have a 5 lb spring and it works fine no problem.

 

60mm you should be able to do to 3. thats just under a 2.5 hole.
We have several 6.2L turcks running under 10psi but we are using a 46mm gate.
If the gate is glitch, you can get another gate and double up, or replace with a larger gate.

 

Reason I ask is because I'm semi sort of in my not being able to make up mind thinking about running a turbo setup. Im told by people with boosted towing experience that I'll want to keep the boost low. I'd want to run ine of the nice BW turbos which will need a big gate to keep it at 5psi or lower. The 76/75 is pretty close to the BW that I'm told I should run.(dont remember what it is, stock48 recommended it but I changed phones so I cant look it up, pretty close to an s480 though IIRC)