Not Holding Boost And Boost Drop

[rhysc1986]

when i bought my R32 GTR when it hit boost it went haywire so we just disconnected greddy profec 2. decided i wanted to get it going again to run more boost and when i installed it it worked fine except when it hit full boost and i kept on accerator the boost would just keep dropping till stock boost 7psi. boost was set at 16psi.

now because the greddy profec 2 was already installed when i bought car i wonder if it was installed incorrectly or if there is something else causing it to not hold boost.

i bought a brand new greddy profec 2 and changed the boost solinoid and main control unit to check it wasnt them just stuffing up and still same problem.

[SiR_RB]

i had the same problem, was running 18.5psi but at peak power boost was dropping to abit under 17psi

cranked up the gain until it held 18psi to redline

they take awhile to set up...

also turning up only the gain, will increase your overall boost. you might find you will have to turn the boost % down afew notches as the gain is increased

trial and error mate until you find the sweet spot

[rhysc1986]

got the feeling it may be the wastegate actuators opening and not being able to hold the extra boost coz it drops down to standard boost. anyway to check the actuators?

[Thelen]

Get it setup properly by a tuning shop, will only take them half an hour and $100, otherwise you could spend days/weeks fiddling.

Won't likely be the actuators themselves, normally this "boost leak" iirc.

[JonnoHR31]

what are the settings in the profec set to?

[paulr33]

are you sure the controller is at fault here or guessing?

i cannot understand the mechanics behind any controller supporting a situation where boost would peak to 18psi (the target)

and then trail off to 7psi with the throttle still nailed non stop

the only situation where this would be possible is a mangled highflow / mangled exhaust / mangled housing or a leaking VAC line

if the controller is toast / faulty / spazzo all it can do is open and close the solenoid incorrectly, or not at all

so it would either run unlimited boost or actuator level boost

i cant see it spiking to 18psi and then running to some secret hidden level, ie less than the actuator spring

check the basics and vac lines? any splits? youd be surprised how easily they split with age

[JonnoHR31]

if you set everything else at its minimum then set the start boost to ~16psi it would do this.

[rhysc1986]

i changed setting a bit and tried what SiR RB had his set to and still did it. exhaust is fine as just changed dump pipes and front pipe and it did it b4 and after install of dump pipes. cat looks fine.

i changed the main unit and boost solinoid with new ones so def nothing to do with that.

wondering if where the standard GTR boost solinoid is should those tubes of been plugged up with screws or should a connector have been put in there?