trying to hunt down a wierd boost issue on my 2004 evo..lost most all boost pressure suddenly did a boost leak test found few small issues fixed those but still only hitting maybe 14psi..its a 2.3l with aem tial blow off valve tial 40mm gate..i even tried capping the wastegate and still cant get more then 10-12psi boost..checked the exhaust as well to make sure it wasnt restricted there isnt any cats etc..i did notice on the downpipe there is a short flex joint that i am wondering if its disengrated inside clogging the exhuast..the turbo is ok i tried a different precision 6262 which made a few more psi then the 35r..had the boost set to 25psi before..there definetly isnt any boost leaks i checked at least 10 times and cant hear or see any leaks using soapy water..it would have to be a massive leak anyway to be losing so much pressure..

 

What is the pressure your wastegate is set at? What are you using for boost control?

 

7 psi spring i beleive..just a plain old mbc routed to the gate and magnus intake manifold..thats not the issue tho i capped the wastegate off and it doesnt change anything.

 

sounds like a MBC issue.. Swap it. and make sure its not backwards.

Doubt its the turbo.. could always pull the line off to check lolol

Add a 1bar spring to your .5 and say screw the mbc

 

+1 let us know what happenes after you swap mbc!

 

Did you ever fix the problem? What was the cause?