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Discussion Starter #1
hey guys, i have an 89t and was having aprobem with my boost. When i go WOT the boost drops off to 6 psi. I have it set up to 12 psi and it holds it fine up to 5k rpm then it drops off to 6. Is this normal? Is it a boost leak somewhere? thanks in advance for the help. i tried searching but it didnt work.
 

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what are your mods?
 

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hmm. well if you have a downpipe you should be around 10psi without having the mbc. i dont know why it would go down to 6psi. maybe weak wastegate spring.
you should check for boost leaks too.
 

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Engine Geek
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check the health of the turbo. mine dropped off like that a couple weeks after i turned up the boost, and it was because the poor old turbo couldnt take the new level of abuse i was giving it. check shaft play and look for oil coming out into the pipes, or any damage to the compresor wheel. mine was really easy to tell. the compressor was chipped at the corners of the blades, and had a good bit of shaft play. all i did was yank the accordion pipe to look at it. i was down to 4 psi after 4500 rpm when i figured it out. thought it was my boost controller setup for a while.
 

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Discussion Starter #6
i have the stock downpipe. There is very little shaft play on the turbo and no chipped fins. How could i tell if its a weak wastegate spring?any other ideas?
 

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Life is BOOST
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I had that problem in the past, My turbo would'nt go past 9-10psi, it would peek at 15psi where I had it set-up with my MBC but would drop to 10psi. I thought that my wastegate spring was old and tired. I shimmed the wastegate, later installed a Profect-B, but never fixed the problem. When i removed the CT-26 when i later Upgraded my Turbo, I found out that my Turbo Exhaust housing was cracked in the wastegate valve area. So that might be your problem, if the other tests fail (Boost leak, tired wastegate spring etc)

Later
 

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Stock downpipe and stock pre-cat I would be is the problem. That first cat is a huge factor in how much boost and how well it can hold the boost. The stock CT is also notorious for falling flat on its face at 5500 and above. If you freed up the stock downpipe and put something good on there, I'm sure you would notice a pretty good difference. That stock pre-cat gets clogged and nasty really quickly and the more miles it has, the worse it is.
 

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BMM
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turbogate said:
I had that problem in the past, My turbo would'nt go past 9-10psi, it would peek at 15psi where I had it set-up with my MBC but would drop to 10psi. I thought that my wastegate spring was old and tired. I shimmed the wastegate, later installed a Profect-B, but never fixed the problem. When i removed the CT-26 when i later Upgraded my Turbo, I found out that my Turbo Exhaust housing was cracked in the wastegate valve area. So that might be your problem, if the other tests fail (Boost leak, tired wastegate spring etc)

Later
i am also having the exact same problem... but i just took my mani off and its perfectly fine... :scratch:
 
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