low boost @ high rpms

[venom2097]

Problem just started a few days ago, car boosts fine to 18psi @~3500rpm then as the rpm increase the psi goes down!
~17 @5000 16@5500 stoping at 15 until 7000 shift.(rpms are approx)
Plan on doing a leak test sat, just wondering if anyone else had this problem?
Also have noticed that on a cold motor my vac now reads 10-11hg when I think it used to read 14-15 on a cold motor, once hot idle returns to 14-15.(high alt norm?)
Have not added any mods or made any major changes in last month or so. Blue silicone vac lines added 2-3 weeks ago.

my thoughts:
turbo dieing or gasket leak

16g
3in exhust
dirty ass air filter(new on order)

 

[CL MaNTis GST]

probably just a leak... get an intake leak test and im sure ull find your problem

g'luck

 

[venom2097]

leak test done, found 3 small hose leaks and fixed.idle vac now back to 15ish.
Still losing boost at high rpms.
any ideas?

 

[Malenko]

sell your turbo and buy a NA car.


Dumb answer? well I get the same kind of answer all the time in the NA forums =)

 

[candela]

....uhhh ok Malenko.... Sometimes the t25 just falls of at higher rpms from what Ive heard. Either that or your boost is probably just spiking a bit then settling back down to where its set to be...

 

[Bohrn]

how do you do a proper leak test??

I followed the instructions in the Vfaq, but the air pump just pushed the air out the exaust ports. Should I just plug off the throttle body at the elbow??

 

[venom2097]

I dont have a T25.

 

[laser9320]

Originally posted by Malenko
sell your turbo and buy a NA car.


Dumb answer? well I get the same kind of answer all the time in the NA forums =)

:laugh: