major boost problem

[SVP97GST]

i've tried searching and no one really has the same problem as me so i decided to post. my car is stock besides thermal ex, hks filter and a greddy fmic. before i got my turboxs mbc i noticed that my boost would spike to somewhere over 20psi then level off at around 15psi. then i installed the mbc, dyno'd it and it did the same thing but worse. boost dropped to about 12psi. it made waaay more horsepower around 4500 to 5500 then dropped drastically. i dont understand why the boost won't settle at a higher psi. the dyno chart looks terrible after 5500rpm. can someone PLEASE tell me what else i can try. i still have the stock uicp(dont laugh)..could that be restricting it?

 

[SVP97GST]

nevermind..i took it to a mitsu shop and i just found out that it's normal to do that with stock turbo's..oh well..bigger turbo time.

 

[BroadyPunk]

your problem is in your bov. The stock bov leaks past 12psi.

 

[nine5raptor]

The problem is the baby turbo.

 

[BroadyPunk]

he can put a t88 on there if he wants, he can put a diesel semi-truck trubo on there if he wants.....he's still gonna leak past 12 psi.

 

[nine5raptor]

Based on what he said, he didn't get a bum cbv like the rest of us.

"4500 to 5500 then dropped drastically"

 

[GSTdOff]

Get a different BOV and you will see steadier boost and be capable of higher PSI. It's like Broady Punk said, stock BOV leaks at around 12 PSI.

 

[BroadyPunk]

Originally posted by nine5raptor
Based on what he said, he didn't get a bum cbv like the rest of us.

"4500 to 5500 then dropped drastically"

the "way more horsepower" in that range is most likely b/c the t25 sucks balls and does nothing but blow hot air past 5500 rpms. In turn, causing the i/c to heatsoak, and not letting any cold air into the engine. timing being pulled perhaps could be another reason.