All the above.....
a) belt sliping.
b) vacume leak and u should b able to hear it if u listen close enough.
c) check the bie bass that leads to ur gage.. unless u dont feel power at all.

 

VRT seems to have fixed the problem. Replaced the Kinetix plenum with stock and the boost is now where it should be. Tuning next week, I hope, and I will finally have some numbers.

 

Are you sure that the Kinetix plenum was not cracked?

 

this is the kinetix V5 plenum we're talking about right?

 

Its the latest version, and there are no apparent cracks. It idled smmoth as silk with it on, and never stumbled. If I had to guess I would say it was a gasket (I've heard of this before), but I wasn't there when it was changed out, so I do not know for sure.

 

A friend of mine had this happen on his G35 with the Crawford plenum. He was idling fine but when he boosted the car would go stupid lean and ping a bit and then one day stopped boosting as much. Found out that the plenum was warped and causing air leaks. Even his vacuum was fine. Switched to stock and it worked great.

 

Same here...no vacuum leaks , but when I preasurized the whole system , found boost leaks all over the plenum . I added more gaskets and no more leaks

 

Alang,

Car runs great.

Looking forward to seeing you at Calspeedway.

M