View Full Version : Need some Ideas, not sure why boost is low.

03-17-2010, 04:27 PM
Okay so ive been deployed a few times racked up a decent amount and dropped alot of it into my car. Its a 98.5 QTM A4 and Performance wise this is my set up:

GIAC pc-16 File, K04 turbo with highflow 034 motorsport mani, APR silicone Intake hose, FMIC, 2.75 turbo back Exhaust with Cat, 315cc Injectors with AFPR sitting at just under 40psi (disconnected from FPR), 007 Diverter Valve, Racing n75 valve from ECS, and some other mods which dont really add to the performance which are recent would be a top end rebuild (due to 90,000 service not getting done so the Timing Tensioner broke slipping timing and bending all intake valves in cylinder 4), timing belt kit, ECS underdrive pulley kit, and a stg 3 Clutch.

So my car is decently equipped with what it needs to perform but on my Swoosh Turbo Timer (was only thing installed on car when I bought it) at full open it rolls straight to 12.1 psi of boost and holds steady until I release. Correctl me if I am wrong but isnt that close to stock psi? I thought I should be some where around 17/18/19 psi of boost. And at Idle it only seems to be -7psi with ac on and -8 psi with it off. Ive looked over all the intake for boost leaks and vacuum hoses for security and all of it is fine. Can anyone enlighten me or give me some direction on how to get more boost?

03-17-2010, 04:45 PM
definetely a boost leak. listen to the engine at idle. try to pinpoint any hissing noises. an extra foot of vacuum line makes for an excellent stethescope.

03-17-2010, 04:46 PM
normal vacuum reading is around 19-21 inches of mercury (in/hg). and boost on a pc16 file should be closer to 20 instead of closer to 10.

03-17-2010, 04:49 PM
Ive looked over and Over again. I will continue to do so but is it possible something is limiting my boost? Such as the n75...