Cant Get Over 4psi On R33

[rnbguy]

hey guys,

ive just taken ownership of an r33 skyline , man you guys are lucky, there freakin fun to drive...

anyway thats not the reason of my post...

my question is, the turbo on this 1993 r33 gtst skyline wont go over 4psi... what could be causing it to limit?

From my previous experience boost limit can be caused by:

a) ecu limiting boost (but its only 4psi not the 12/14psi margin)

b) boost leak (will need to pressure test it)

c) exhaust leak in external wastegates however its an internal in this one

d) screwed turbo (hmmm?)

I dont mind if its any, as im confident with the help on these forums i can change it, can anyone think of another issue?

i notice a slight whislte noise when im driving but i dont think thats turbo related as it doesnt get louder, its more constant, and only happens when im moving (if it where turbo i think itll happen slightly while idle as its still spinning)

i just need a bit of your nissan experience on this kind of issue if possible.

[murrayis]

Whats it like to drive? does it cough and splutter at all?

[QWK32]

sounds like the stock boost solinoid isn't operating properly. it isn't switching to 'high boost' (7psi), from low boost (4psi).

Edited January 27, 2009 by QWK32

[teng]

I had the same problem. When i got my R33 it was only boosting at 0.4bar MAX. After numerous $$$$ and fiddling, i still couldn't find the problem. In the end i just bought a HKS Adjustable Actuator and adjusted it to 0.73bar and it fixed the problem permanently. I still don't know if it's a solenoid problem as i can't get my hands on a used one. The whining noise was even louder now than when it was in 0.4bar

Edited January 27, 2009 by teng

[geraus]

Hey mate, Try and get a manual boost tee and set it up to 8psi. it sounds like your solinoid isnt working properly. I;ve seen this happend before on my freinds car , when he unpluged his boost solinoid it melted and then we tried to fix the cable but didnt work.

[rnbguy]

thank you for the replies guys, is there anyway to bypass the solinoid ive read stuff on disconnecting it and putting a straight plastic host instead of it?

[rnbguy]

okay more research done on this forum and know i understand on the solinoid the top goes to plumb back (air intake) and the botton of the solinoid goes to a T which intercepts the actuator and the intake (seing boost) correct?

[adis]

I recommend you get your self a "turbotech" manual boost tee, off ebay. I did it. Works really well, what ever u set it to, stays there.... pretty impressive. im running it on 10psi.

[adis]

ahh and it only cost 37 bucks, delivered.

[Turbo Dave]

What boost gauge are you reading this off?, not the stock one in the dash I hope coz its not in PSI.

[cmoney]

+1 for the boost gauge you're reading this off.

Without any smoke from the exhaust, the turbo should probably not be stuffed. Just stick a proper dual stage (turbosmart or equivelant) unit in & set the boost to what you would like to run.

[rnbguy]

nah i have an after market ebay job gauge, im curious how the stock solinoid is connected , my assumption is the top hose goes out into the air intake system... the button hose sits between a boost source and the actuator correct?

does it matter with the top hose which point its supposed to plumb the air too (e.g. pre any sensors?)

[errno]

What boost gauge are you reading this off?, not the stock one in the dash I hope coz its not in PSI.

what does the dash boost gauge measure?

[R31Nismoid]

mmHg, so about 3 on the stock gauge is 7psi IIRC

[teng]

mmHg, so about 3 on the stock gauge is 7psi IIRC

Most aftermarket boost gauges come in x1000kPa hence the stock will move and show the same pressure as the aftermarket one. I know mine does.

[QWK32]

Most aftermarket boost gauges come in x1000kPa hence the stock will move and show the same pressure as the aftermarket one. I know mine does.

more like x100kPa (BAR). and unless you get an aftermarket gauge that reads in mmHg the stock gauge will read different to the aftermarket one.

also +7mmHg on the stock gauge is about 10psi.

[rnbguy]

issue fixed, the guy had the bov top port disconnected.