9Bs - 3000GT/Stealth International Message Center

4wheelpeel · 05-26-2008, 05:07 AM

Hey everyone,

I'll start off by again saying thank you for all the help so far. I have yet another question.

I have searched the board and am confident that what I am experiencing is somewhat normal on a completely stock car.

I know from searching that 9Bs will not hold peak boost to redline but my question is. When I get on the car in say 3rd gear I can spike 12 PSI on an aftermarket gauge for a second or so and then it seems that I fall to about 6-7 PSI. I know 9Bs fall off towards redline but I would say I am falling to 6-7 PSI by about 4000-4500RPM. The car has 180000KMs (111000 miles) and so do the turbos. Is this normal for the 9Bs?

I have not yet pressure tested the system, and if I were to pressure test where would be the most vulnerable points on a stock setup?

VR3.9 · 05-26-2008, 07:48 AM

I would say it's not normal. Mine has over 220,000 miles on it. In 3rd they hold 14 pretty well.

Definetly need to pressure test. Some likely spots for leaks.

O-ring on pipe going into rear turbo.
Biss screw on TB
o-rings on TB shaft (rebuild tb)
Stock BOV
Pretty much and and every hose and connection. LOL.

Mine leaked even through the hose. When sprayed with soap water they all just bubbled right through the hose.

Monster Stealth · 05-26-2008, 08:18 AM

What are you using to actually control the boost? The type of controller you have (EBC or MBC) will effect your boost response and curve as well. I would pressure test first though, that needs to be done no matter what.

4wheelpeel · 05-26-2008, 10:40 AM

Yeah... my friend built a pressure tester so I am going to get my hands on that ASAP. Just need to get an air compressor for the test. I am just using stock selonoid to control boost, I removed the restrictor plug. BTW I have a 92 RT/TT

05-26-2008, 05:07 AM	#1 (permalink)
4wheelpeel New User - Please be kind Join Date: Apr 2007 Trader Rating: (0)	9Bs Hey everyone, I'll start off by again saying thank you for all the help so far. I have yet another question. I have searched the board and am confident that what I am experiencing is somewhat normal on a completely stock car. I know from searching that 9Bs will not hold peak boost to redline but my question is. When I get on the car in say 3rd gear I can spike 12 PSI on an aftermarket gauge for a second or so and then it seems that I fall to about 6-7 PSI. I know 9Bs fall off towards redline but I would say I am falling to 6-7 PSI by about 4000-4500RPM. The car has 180000KMs (111000 miles) and so do the turbos. Is this normal for the 9Bs? I have not yet pressure tested the system, and if I were to pressure test where would be the most vulnerable points on a stock setup?

05-26-2008, 07:48 AM	#2 (permalink)
VR3.9 Forum Member Join Date: Sep 2007 Location: Allen, TX Drives: 93 VR4 & 91 VR4 Trader Rating: (8)	Re: 9Bs I would say it's not normal. Mine has over 220,000 miles on it. In 3rd they hold 14 pretty well. Definetly need to pressure test. Some likely spots for leaks. O-ring on pipe going into rear turbo. Biss screw on TB o-rings on TB shaft (rebuild tb) Stock BOV Pretty much and and every hose and connection. LOL. Mine leaked even through the hose. When sprayed with soap water they all just bubbled right through the hose. __________________ FIPK, Megan Racing DP, Gutted Pre Cats, MBC, Walbro Fuel pump, Ground Controls, Unortodox Racing Flywheel, Slotted and Vented Rotors. Maximal Rear adjustable upper control arms. Poly Mounts Under the Knife for: JDM motor with 25k. 13T's, 550CC injectors, SAFCII. Rebuilt 5 speed 25spline tranny.

05-26-2008, 10:40 AM	#4 (permalink)
4wheelpeel New User - Please be kind Join Date: Apr 2007 Trader Rating: (0)	Re: 9Bs Yeah... my friend built a pressure tester so I am going to get my hands on that ASAP. Just need to get an air compressor for the test. I am just using stock selonoid to control boost, I removed the restrictor plug. BTW I have a 92 RT/TT

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