i have a grimspeed 3 port installed on my evo 8, it was working fine till i had a timing belt failure. After that when ever i used to go into boost it would make this very high pitch noisy sound like the turbo is surging.

here's the sound it was making, you can hear it at 3 second mark
the sound would cause the boost to decrease and the car would have over 30 counts of knock.

yesterday, i removed the grimspeed solenoid and went to wastegate pressure only, the noise is gone and car runs fine.

my question is, has the grimspeed 3 port gone bad or is it some other factor causing it?

how can i check if my 3 port is working or not?

 

1. Make sure it's plugged in (I know.. but you would be surprised...).
2. Triple check the vacuum lines to be sure they are attached to the right ports,
3. If they are correct, Check and/or replace all vacuum lines in case one or more has a split that you can't see.

 

thanks,

i have a PT6466 turbo and a tial wastegate which vents to atmosphere

can you verify if this is correct, port no 3 goes to turbo inlet,port no 2 goes to wastegate bottom port and the top port of wastegate is left open to vent...is this correct?

 

The middle port with the vacumme line is going to the turbo nipple ..the port no 2 on the left is going to the wastegate bottom port and the right port which is port no 1 is just left as is ..is this correct?

 

If that's what the instructions say, then yes. I don't know off the top of my head.

 

Port 1 - Intake
Port 2 - Wastegate
Port 3 - Compressor Housing

 

Port 1- intake Or nothing, like he originally said vent. So both are correct