I recently got a ported and polished s/c and i had a 2.8" pully on it. It hit 17psi on the 2.8
More recently i swapped the 2.8 for a 2.6, but now I'm only hitting around 16psi. I have checked for boost leaks, and i couldn't find anything, but i plan to check again just to be sure. I cannot figure out what the problem could be, so if anyone could point me in the right direction it would really help.
As far as cooling goes i currently have it set up with a zzp s3 heat exchanger and the zzp single pass intake manifold

 

check for any leaks post blower. particularly the SC gasket. and if not do the boost bypass mod to make sure it is not bleeding off boost

 

put the 2.8 back..

 

what is the boost bypass mod?

 

if you upgraded your exhaust recently, that could make your boost appear lower.

 

yea but even with the new exhaust and stuff it should still be boosting more than 16-17 psi on a 2.6