Hi guys,
I have been playing with the PFC boost setting and using the PFC as a boost gauge and controller. My question is, I am setting my boost @ .90 bar on both primary & secondary, and about 62% on both. When I get on boost, I notice I will only get about .84 bar on 2nd gear, and about .92 bar on 3rd, and 4th gear would probably get me .98 bar or so. Is this normal to have lower boost on lower gears? I also understand air temp has alot to do with the boost as well. Most of the time, I see air temp about 42 - 50 on my PFC.
TIA

 

Lower boost in lower gears is normal, the engine doesn't have the load/airflow on it/through it, that it has in upper gears. It is also probably overboosting due to the wastegate not being able to get rid of enough air. If setup right with a good controller, not the PFC, the boost should stay the same no matter what the air temp. Boost controllers typically read pressure and 10psi is 10psi. The O2 density may be different, causing it to go lean/rich, but the pressure is the same.

 

Is your wastegate ported?

 

My wastegate is not ported

 

Even a stock port FD engine with stock turbos and open exhaust will have boost creep. Your ported engine HAS TO HAVE THE WG PORTED. I doubt that a cat-back pressure restricter will work for you.

The PFC boost control is also a poor boost controller because it does not have/use any form of feedback for boost regulation.

You did not do your homework before going this route.

 

Well, that's the problem then. You are boost creeping. The shorter gears don't present enough load for a long enough time for you to start creeping but the higher gears do. You'll need to port the wastegate or run a restrictor plate to fix this.

 

where can I get a restrictor plate?

 

You make one or run a search in the 3rd gen section, some guy was making them for members.

 

It is nothing more than a piece of stainless steel (1/16" thick) with about a 2.5" opening in it that goes between your midpipe and cat back. Use the gasket for that location as a template but make the opening 2.5". That worked on mine until I re-ported the WG ( I did not port enough the first time).