Boost keeps Changing.. What could be the problem?

[99GsxMD]

I think its the wastegate, but i could be wrong. I need a boost control, any idea's on a good one to get? Anyways, my average boost is 15, spikes at like 16.5. I sometimes get like almost 19psi, and it scares me cause i know safe is around 16. It only spikes at 19 but then drops slowly to 15-16 psi. What else could i check?

 

[dsmdegier]

It's normal boost creep. I'm guessing your running the stock T-25? If you get the exhaust housing ported it will control the creeping. Also if it's spiking all the way up to 19 it could be a sticky wastegate.

 

[Gstclipse69]

A standard well known ball and spring boost controller is the hallman pro, available at several of thes sites vendors. Most people prefer a ball and spring boost controller over a bleeder. As for the boost creep, you need a bigger exhaust.

 

[99GsxMD]

I have a full 3" exhaust, turbo back.

 

[My1GLaser]

That is actually contributing to boost creep. A less restrictive post-turbo exhaust will reduce backpressure. This allows the turbine to spin faster with the same pre-turbo exhaust flow as you had before the upgrade. Has the problem started since your upgraded exhaust? Porting the turbo wastegate entrance helps control boost creep. http://www.dsmtuners.com/forums/art...oler/186525-how-cure-boost-creep-porting.html

I have a Joe P. MBC and its a great boost controller for $45.

 

[99GsxMD]

I am looking for a MBC, and i would get a Joe P. MBC, but it is cheap so i am kinda curious about it. Anybody else have MBC idea's?

 

[markp]

I have a joep IL series mbc and it works pretty well. It holds boost very steadily at 14psi for me on my 16g with a 1 psi spike. Just because it's cheaper than the hallman doesn't mean the quality is any worse. There's also a review on the joep mbc somewhere in the reviews forum if you search for it.

 

[Calan]

As for the boost creep, you need a bigger exhaust.

Completely backwards . A bigger exhaust can actually contribute to boost creep, as My1GLaser explained above. Search around a bit.. there are 348734872 threads on boost creep, what causes it, and how to cure it.

I might have missed it, but how are you controling boost now? If you want to take the boost controller and WGA (waste gate actuator) out of the loop and test to see if your housing is physically creeping... disconnect the WGA actuator rod from the flapper on the turbo, and tie the flapper open (open is when the WGA rod is extended) with some wire. This means the WG is always open, which should prevent any boost from being developed at all. If you still see boost building, then you have issues with your turbo housing (very common), and you will need to do some porting to resolve it; otherwise no boost controller is going to make a difference.

As for the MBC, if you have any mechanical aptitude at all you can easily make a good ball and spring type with a few $ worth of common hardware store parts.

http://www.geocities.com/chmwatson/FAQs/mbc.html

 

[MrBoxx]

I recommend the TurboXS High-Performance MBC. It has maintained rock-solid boost for me.

Port your turbine housing for creep.

 

[srumel]

Have you checked the vacuum lines that are connected to the wastegate? A poor connection or a torn hose could be contributing to your problem.