is a 38mm wastegate ok for 20 to 25 psi

 

yes

 

yes!! but a 48 would not hurt!!

 

38mm is good enough......

 

its not really psi that matters, its engine flow, manifold design, turbo size and power goals.

the higher boost levels you run, generally the smaller the wastegate. but for street use generally bigger is better.

im using a 44mm tial in my build

 

38 mm was to small in two of our cars they started creeping at about 6500 rpm and a lil over 500whp so we are switching to the 44's let you know what happens

 

would 38 mm be ok for say 500 to 650 hp with a H.O. 67 82 ar

 

its gonna creep really bad on the street