Recently stationed in Japan and got my hands on a stock (other than hks bov) Evo IV. Of course it came with problems. In 3rd right about 4500-5000 rpms there is a super loud knock and the car kills power. After doing some research i'm fairly confident that it's the fuel cut from over-boosting. The car is stock vice the BOV so i'm looking for ideas on what and how to check problems that would cause this. We pulled the boost gauge off of my buddies GT-R and tapped the FR vaccume to check boost. It's idling at just under 1 bar, probably about 10 psi. From my understanding it should be in the negative while idling. I thought it was the gauge but it worked fine after being hooked back up to the skyline. I'm in dire need of help here.

 

fix the bov first. a broke valve will cause major problems under boost

 

lol. I was thinking the same thing, sadly, my BOV post was the only one of the three that nobody responded to

 

you are under boost when idling?


you should be under vacuum when idling shouldn't run more then 15-16 psi or 1.1 bar on a stock E4 motor.

 

i'm sorry if i confuse anybody as I'm very new to the turbo stuff. I used to be an all motor mustang guy before being stationed here. We tapped into the vacuume line for the FPR and hooked up the boost gauge which showed the amount of boost i mentioned above at idle.