boost spike creep? help please

[talongod]

my car is set at around 17 psi when i wot the boost goes to 17 or a little higher and then goes down to like 13. i have no clue what it is i seached already and didnt help will anyone please help

 

[girlieracr4g63]

Have you checked for leaks?

 

[tstkl]

are you sure its just the t25 giving out(altho i think 17psi is a little high for a t25), even tho it should be able to hold more than 13 psi to redline, i know from being around the 3kgt forums that a small turbo=really low boost to redline,.... (the 9b is like the smallest in the world,... ) check your manifold for leaks, im not sure i know exactly what boost spikes are, but i thought it was when your turbo surges extra boost at random, so it doing it consistantly at wot wouldnt be a spike, it would be just an increase in the engines byproduct (exaust) and the turbo being able to spool fast,...

anyone want to define creep/spikes better so he can tell us what he thinks is going on?

 

[talongod]

i have a greddy 18g turbo with all supporting mods

 

[oldman]

http://www.dsmtuners.com/forums/showthread.php?t=174083

I see that you still have not done the leak test yet. What about the actuator test?

 

[talongod]

my last post was fixed by my exhaust i guess my fle pipe broke off i weleded a new one on and fixed it this just started to happen

 

[talongod]

can anyone help me please

 

[oldman]

i have a greddy 18g turbo with all supporting mods

Update your profile please, it would make it easier for us. Let's do a couple of test, hopefully you will follow them this time.

1. Disabling the actuator. Disconnect the hose between the mbc and the actuator and plug up the mbc nipple. Doing this should give you uncontrollable boost so feather the throttle and keep it at 17psi to red line. If you're able to hold 17psi steadily, you have a bad mbc. If problem with the boost drop persists, go to 2.

2. Perform a complete pressure test, fix all leaks big or small until system holds 20 psi for at least 30 seconds. If problem persists after this, you have a dying turbo.

Good luck.

 

[talongod]

ok thanx alot will do ill get back to you