Hey guys... Just picked up my new-to-me evo... I no longer have a boost leak tester, as I haven't owned a turbo car in a while, but I do intend on making one later today. Boost tapers/falls off at just over 6k rpm's to about 7 psi. It holds great until 6k or so and then I can hear a decently loud hissing from the drivers side area? Anyone care to shed some light or point me in the right direction? I've checked all my clamps and hoses, but still nothing... The car is a stock (for now) 05 MR.

 

Hey man, I had the same problem, mine was my throttle body shaft seals, when you do you boost leak test pull on the throttle body cable to make it wide open throttle. There are how tos on how to install new seals and they are cheep. Also check the throttle body gasket as well. Hope it fixes your issue

 

Thanks man... where did you find one? Mitsu claimed they didn't list the part and neither did my local auto parts store..

 

nm that... I guess mil.spec it is!

 

Cant go wrong with mil spec seals, if your tb isnt leaking yet on stock seals..it will.

 

Yeah, It's got 65k miles on it. I have everything cranked down good on my crappy stock ic piping. Still yet to do a boost leak test on it. Either way, I'm going to order the shaft seal and gasket...

 

Do the test first, the seals might be good.

 

injector seals are another likely candidate. Also your EGR valve vacuum line.

 

Still haven't done an actual boost leak test, but I received my throttle shaft seals and gasket today. Installed them, and and it's good to go now! The throttle is a little different feeling with those seals in there... Like maybe a little more sticky, but nothing bad. I haven't driven it a lot since putting them in, but did a little drive around and several pulls. It feels great and I'm not losing any boost. I still need to do a boost leak test on it, just to make sure I don't have any other notable leaks... Nonetheless, the car pulls hard and feels good!

 

Do a boost leak test! Do not guess, the health of your engine is in jeopardy!

 

Falling a little bit is normal

 

What BOV are you using? Sounds like the BOV valve is leaking under high pressure.