Little issue.... Searched and searched.....

[RhdHybrid]

Ok, so here it is....

92 GTR, Stock Turbo's, Divided charge tube, Aem Meth, Aem Wideband, Aem Tru boost, Nistune. Blitz BOV's, Mine's Downpipe, 3.5" Exhaust, Apexi Filters, stock MAF's.

Problem:

I can't boost passed 9.5psi. The tru boost is showing a peak of 11.8 but I can't see it in the datalog or on the Dynometer datalog. The car is running 11.3 under boost, and running nicely in all cruise area's. As I turn up the percentage on the truboost, my boost is falling off to 8.5psi, if I turn the Tru boost off I can see 10 psi... Sometimes... The car drives fine on the street, but every now and again the car will hesisitate for a second, if I slack off, then get into it again, it will be fine.

Attempts to resolve the Issue:

1) I have check all the charge tube clamps, all are tight. one is in questionable condition (Stripped out alittle), but it is tight. I'll be replacing as soon as I get back onshore.
2) Tighted the adjustment bolts on BOV's.... Not sure if this is the problem or not..... May need new springs....
3) Swapped the lines going to Tru Boost solenoid, no change in anything. I have it hooked up as per the AEM instructons now.

So this is where I stand... At a lose.... But it did 267hp and 254lbs on 9.5psi, Dynodynamics 2wd dyno, with no meth. Didn't see the point of going any farther with out consistent boost control.

Come on with the idea's....

[bobbo]

I'm assuming you have the boost restrictors removed? I would really like to see how you have it plumbed.

[Black BNR32]

pressure testing your intake and exhaust systems is probably the best way to be sure of no leaks. visual checks just don't cut it.

[Dragon Humper]

Where are you taking your boost readings from and are you using a mechanical pressure guage to confirm boost level or are you just looking at the sources mentioned in the first post?


Jon.

[RhdHybrid]

Thanks for the responses guys.

Bobbo: I have the boost restictor removed, well the previous owner removed it. I have the stock boost solenoid removed and the aem soleniod in it's place. But I'm going to run my own wastegate lines and charge lines for it when I get in.

Black: This is on my list of things to do. The exhaust is good, it is all brand new, and I checked it when I had the car up on the ramp before the dyno run. No leaks.

Dragon Humper: I have the truboost tied into the factory Map sensor line. I also logged the boost on the dyno (tied into the Fuel pressure reg) and then compared the Nistune, dyno logs and they both appeared to be the same... Except for the peak boost reading that the truboost is showing, but this is only everynow and again that it shows a 11.5ish. The rest of the time the peak boost is 9.5ish or 8.5ish depending on the mode I have the tru boost in.

Mode A: 35% duty cycle = 9.5ish
Mode B: 55% duty cycle = 8.5ish
Off: 9.5 - 10.5 psi...... Doesn't make a great deal of sense.

Are Blitz BOV's known for getting weak springs over time? I'm leaning on this as my problem, just because they were used when I got them....

Also is the Factory IC piping known for stress cracking or dry rotting?

Thansk Ken

[Black BNR32]

check yo wastegates

[MattiasJacobs]

Have you checked what shape your turbo's are in? I recall only making .6 bar with my R33 N1's before I swapped them for -7's. There was soo much shaft play that they were pretty much shot.

[derbeck]

You cant just replace your old boost solinoid with the new boost controller the original uses manifold pressure as well as the actuator pressure. simply unplug actuators run a line to each actuator put a t to the two lines and in to the controller than unplug the line that connects the oringinal solinoide into the manifold and run a line from the manifold to the other end of the controller. plug the other end of the old solinoid lines

[RhdHybrid]

Derbeck: You have enlightened me sir. I didn't realize this. So I'll reroute my lines as soon as I get onshore. Thank you sir. Fawk now I got two weeks out here before I get to see if she is going to work right.... LOL.

Thansk for the other points as well bye's. My turbo's are in mint condition thou, I checked the shaft play when I had all the intake piping off. All is well in that respect. But as soon as they go, -5's are in store for her. _

[derbeck]

Good luck hope it works