Driving home yesterday i gave the motor a good work out, then about a mile from the house i hear a loud scretching when the boost is up. Sounds kind of like metal to metal or air pushing out some where, but the boost still touches 65-70 like normal. Cant find anything that seems to be causing it. Checked the turbos and wastegate, pulled the valve cover, all looks good. Anyway it could be the headgasket?

 

only does it over 25+ lbs. of boost, and all is well revving it

 

check your boots and clamps ? how about your intercooler ?

 

all the boots and cooler are good