i know i know i've tried searching...but my searching skills aren't as good as some of you out there :P

anyways...here is my problem.... boost doesn't stay consistant...it has a 11-9-10 pattern...then...as the rpms climb...boost starts to drop off...it keeps dropping until it hits about 5-6 psi. and it kinda stays consistant there. Mods: dp, cb, manual boost controller ( i know...but it was all i could afford at the moment).
Any ideas folks? anything would be greatly appreciated.

 

There is nothing wrong with a manual boost controller. Unless you change your boost levels (and tuning to match), you don't need a $300 electronic valve opener/closer.

Clogging main cat is probably what's wrong with your boost.

 

A failed/failing cat is the most likely culprit.

 

hmm...thats gonna lead to more and more mods i like that haha so i guess i should replace the main cat, and see what happens? will the MBC still be ok with an added mp? or high flow cat?

 

In addition to a clogged cat, an air intake restriction (collapsing hose, clogger air filter, etc.) can also cause boost drop-off at high RPM's.

 

will the MBC still be ok with an added mp? or high flow cat?

 

Yes, boost control is boost control, and there really isn't a way to outgrow the MBC.

The midpipe however can cause boost creep, which, if it happens, requires that you port the wastegate opening. So a mp can cause boost issues, but it's not related to the controller.

Personally, I'm not a fan of pollution, stinky cars, and extreme noise, so I will always recommend the high flow cat.

Dave

 

i'm not a big fan of it either...but the costs of a hi-flow esepecially in san francisco california! *sighs*
porting the wastegate? damn....taking the turbo's out while the engine is in the car isn't fun *sighs...again* haha anyways thanks for the info! i'll try these things out and see what happens

 

I have a stock cat that should be in fine condition, if you end up needing one. I would remove your existing cat to make sure it's the cat first, though.

 

how can i tell by just removing the cat?

 

By finding a known good used one somewhere and swapping it out.