I recently installed a 4" exhaust on my truck, did not see a big difference. Before adding the 4", I was maxed out at 32# of boost. Yesterday while driving to work, I had to wood it to get around slow traffic and I noticed 38# of boost. Will this hurt anything? The turbo is stock with the TST elbow. Which way do you turn the allen head screw to back it down ( if needed ). I run empty 98% of the time.

 

You will see a difference in EGT when loaded heavy or climbing a long hill. Or if you drag race. Otherwise no need for the 4". Your truck is a workhorse, running empty has no requirement for power.

If your boost elbow is brass with a setscrew, tighten the setscrew to reduce boost. Mine is bottomed out and I get 28 PSI max. No need to produce more than 36 PSI, above which you are just making hot air. Better have a pyrometer if you make more than stock boost (22 psi) or you chance melting pistons.

I'm assuming you have a Cummins diesel? 12 valve? Please add signature info.

 

Thanks for the reply, I do have a pyro and a 12v. I just don't want to hurt anything running too much boost. I did my sig info and have no idea why it is not there. I have a #8 plate centered and a BHAF.

 

If you tighten the set screw you'll completely shut off any airflow to the wastegate actuator. You want to loosen the setscrew.

 

My bad! What was I thinking? You are right, Mike. Back out the setscrew to reduce max boost.