What could cause a 8-8-10 boost pattern? Ever since I installed my PWR radiator, I don't get full boot on the primary anymore -- it also takes forever to build up 8psi. Could it be the couplers or something of that sort?

 

While installing could you have kinked or pulled a hose out?

 

I don't think so -- I didn't go near the vaccum lines.

 

Nor the ones near the acuators? Cause that would probably be the most likely ones.

 

I don't think I did.

 

Check your two vacuum lines leading from the intake side of the primary turbo (just before the compressor housing). Those two can get jostled around when you're messing with the radiator and fan brackets.

 

It leads from the primary turbo to which other line?

 

they go to the wastegate and turbo precontrol actuators. They are in close proximity to the left radiator hose so there could have been some contact with those vacuum lines.

 

I readjusted my manual boost controller, and that didn't help much. Could it be my couplers? I was thinking that it couldn't be it because I still get full boost on the secondary.

 

Check the boost at the Y-pipe and you will know for sure.

 

Did you check those two vacuum lines that lead to the TPC actuator and wastegate? Make absolutely sure they're on tight and not cracked and hard from heat cycling.

No, it's not your couplers, because secondary boost would immediately cause a leak.

 

If it were me, I would check for a boost leak. If it is a small one, both turbos can overcome it to make 10psi, where as just the primary cannot. I've had this happen before, so it is a legitimate possibility. If you still have a stock y-pipe, I'd check that first and then the lower IC hose for cracks.

I'm gonna say probably not a vacuum line since it's only the primary turbo.

 

The weird thing is that my vaccum is still normal at idle 16-18in/hg(depending on the elevation). Would that mean that it's somwhere in my couplers/pipes?

 

Check the precontrol rod, the C clip might have fallen off the precontrol wastegate.
I had the same problem last week, slow build in primary full boost in secondary.

 

Do you have a pic of that?

 

You'll be able to see it from under the car.