ok so there's a million threads on this already and i'm sorry, but i did read them and the scuderia site write up.

my pfc was recently tuned by steve kan and in what time he had with it could not figure out why it would not hold 1bar to redline. holds it in primary, hits it after transition, but drops to 12lbs as the revs increase. steve didn't think too much of the pfc's boost control (without optional kit) and recommended the profec b. granted it could just be turbos getting tired or a boost leak somewhere but what about the pfc? could that also be it? would hate to invest in a profec and get no results.
also, what range of duty cycles should it be set at for 1bar?

 

4 cars here with the same problem...one with new BNR's so it's not the turbos...who knows?

 

Sounds like the stock solenoid cannot bleed off enough boost ...

 

That would result in too much boost, not too little.

 

rynberg,

does the stock solenoid vent air from the wg actuator to control boost?

if the stock solenoid does not vent any air then the wastegate will open once the pressure in the wg actuator approaches or exceeds wg spring pressure. similar to what I mentioned earlier, if the solenoid does not vent enough air the wg actuator will open the wg more than desired and you get lower than desired boost

I might be dreaming all this; got a cold and not feeling too well

 

attached excel spreadsheet of datalog with 2nd set at .95 with PFC....boost gauge read approx 14.2 psi...assume 1.0 would not be a problem

 

I wouldn't be too quick to blame the Power FC. There are way too many of them out there without the problem you describe.

You mention that the primary holds the 1 bar boost but fail to mention the average RPM where the transition hits. Many boost "leaks" (including those on single conversions) I have seen evidence themselves only at higher RPM's (don't ask me why but I have a guess that it has nothing to do with higher RPMs but instead has everything to do with the length of time the system is required to hold the higher boost pressures).

A profec B is a great controller and never a waste of money, but I would suggest before you spend the money, you check the entire turbo system for leak possibilities. Other than the usual connections (solenoids, hoses etc.), I would suggest looking carefully at the following:

1. gasket between the intake elbow and the Throttle body.
2. manifold connection between the manifold and engine
3. manifold connection beween the manifold and turbo.

Good luck