ok guys i need your help on this. first my problem is that i have a giac chip and after 4,ooo rpm my boost slowly drops from 15 psi to 10 psi. i knwo that this is not normal. i need help beuase we tried eveything this weekend and the problem is still there. we checked the waste gate, the DV and even some little unit that controls the boost under the headers. and still no answer we lookd for leaks and couldent find any. i was wondering cold this be a leak that i just cant see? im doing a pressure test this week to make shrue its nto a leak but if it isent what could be doing this? please guys i need your hlp beuase my car has been liek this for a week.

 

It could easily be a leak that you cant see. Do the pressure test and let us know what happens.

 

possibly a bad n75 valve... could be really anything. Definitely check for the boost leaks. Do you have a fmic?

 

still the ko3? even the sport cant keep putting out 15 psi,.....mine drops as well... its normal. unless its bogging and losing power.

 

ya im doing a pressure test this week and was told by giac that its not normal for the pressure to drop at all. it should be 15psi all through the rpm range. im gonna see how the pressure test goes this week.

 

The psi will taper as the rpm's get high - anything over 5200 and the psi should start to fall off. 4000 rpm is fairly early - you are right in your sweet spot and the psi should hold at 15 at least for another 1000 rpm.