What is the highest boost pressure that the stock 04 Evo * motor can handle without sacrificing its reliability. Stock is 18 psi would it still be safe to go to 20 or 22?

 

22 is safe

 

22 psi is definitely safe, when i was on my stock 03 turbo, i went 24 psi peak held 21 to redline which is out of its efficiency range got 20+k miles out of it, but the car already had 39k when i bought it. Its all in the tune, and makin sure the engine and turbo are mechanically good then you shouldnt have an issue.

 

The stock turbo likely can't produce enough power on pump gas to destroy a motor but the tune can kill it, also you can easily spin the turbo out of it's efficiency range and kill it long before the motor will die

 

i have a stock evo ix turbo and I spike to about 25psi

 

I have an 04 still with the 8 turbo and I'm running 25psi.

 

Ha your form Guam. Cool. I was there in Navy for a few yrs and saw only 2 evos there and at the time the dealer wanted 52000 for a brand new one. How many Evos are there now?

 

Quite a few from VIII GSR, MR, RS to X, there is also a Mitsubishi Club of Guam.

There is no longer a Mitsu dealer on guam.

 

Thanks for everyones input. There are no tuners on guam and my car is stock except for an ARC intake. I will set the boost at 22 psi. The car has 50K miles on it. Will this destroy my OEM BPV (plastic)?

 

destroy it no, but there is a chance down the road it might start leaking, you can either get a ix valve which is metal for higher boost, or eventually when it goes out look into an aftermarket one. Dont replace it until it breaks haha

 

How will I know if it has leaked?

 

usually if it doesnt hold the boost level it should be at, then usually thats a sign, stock plastic 8 diverter valves are known for leakin usually a couple pounds above stock levels.

 

What is the octane level of the gasoline that you are running in your Evo, OP? In Guam is octane rated using the RON method( RON=Research Octane Number)?

 

Yes I beleive so 91 RON