Stupid Profec Is All Over The Place...

[GDZ-14R]

I had my car tuned last week on 12 and 14psi with a Profec B II. When the tune was done on the dyno, it spiked 0.5psi on both settings and settled to the desired setting. However on the street it is spiking by almost 2psi on each setting - which is not what anyone wants with the stock turbines.. I have turned the gain down on high and low settings but the variance is still too ridiculous for a controller with such a good rep.

My question is have i set it up right? I have left the standard Nissan solenoid plugged in but blocked one of its lines. I have tee'd the actuators in to the Greddy solenoid, which i know is right. The part i am not sure about, i have tee'd the hard lines that come from the intake manifold (before the throttle bodies) and fed that into the Greddy solenoid as the pressure source.

Please if anyone can pick a fault in my config let me know!!

[Moodles2]

The source for the pressure reading might be too laggy, fuel pressure regulator source might be better.

[Tangles]

Mine was on 10% set gain, and was overboosting (from 15psi up to 20psi) heaps as it'd get up to max pressure quite quickly

reduced set gain to 7% and it is much better, boosts to 15psi and only overboosts a little now

[PM-R33]

Under certain conditions they will spike, just the lag it takes to open the wastegate and for the exhaust gases to redirect, not much you can do about it. Say im in second gear half throttle at 4000rpm and then put my foot down mine spikes to about 22-23psi and then settles back to a bit under 20. As long as it doesnt spike a ridicolous amount for too long i wouldnt worry about it. Its heat generated from high boost that will kill your stock turbo(s), a little spike hear and there won't kill anything.

Edited November 21, 2009 by PM-R33

[JonnoHR31]

spike in the midrange wont hurt the turbos, still flowing a lot less air than they are at peak power.

try turning the set gain down a bit, this is the pressure the solenoid lets the actuator see boost (not a %, its a set pressure), if its too close to your target boost the actuator wont open in time to hold boost steady and it'll spike. usually 2-3psi below target boost works well but try it really low at first and see if your spike goes away, then slowly turn it up until its right