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Discussion Starter #1
Hi folks,

I removed the boost restriction this weekend and enjoyed driving around with exactly 1 bar of boost.

After a few hours of driving around I and hitting 1 bar of boost regularly during acceleration, I decided to head back to my garage. On my way back I did one last drift across a junction again hitting 1 bar without any problems. A few minutes later I tried to overtake two cars uphill and there I realized the car wasn't pulling that strong any more. On the next straight I pushed the pedal to the floor and watched the boost gauge. 0,6 bar!
Tried it two more times but the result was the same. I hit the 0,6 bar pretty fast, around 3.5k but then it's kind of stuck. The boost won't get higher anymore.

Back in my garage I checked the connections of the PCM Valve and the hoses fitted on the actuators, but none of them was loose or blown off.

I'm pretty clueless at the moment and I thought perhaps one of you can help me out.

Cheers,

Leo
 

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Discussion Starter #3
No not yet, as I thought boost would drop way more if any of the IC pipings is leaking.

Curious thing is that it hits the 0,6 pretty fast and it holds it all the way up the revs...

... isn't the standard actuator spring rated for 0,6 bar???
 

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Discussion Starter #5
Please correct me if I'm wrong, but if there's a leak in a vac line, wouldn't this mean that the turbos will overboost???

Cause when you think about the standard boost controller setup, the PCM valve relieves some of the pressure into the suction pipe, so there's less pressure going to the actuators which means they remain closed longer and so boost is increased. On the other hand when you block off the PCM valve the full pressure goes to the actuators which means they'll open earlier and the boost is lowered.
So if there's really a leakage in one of the vac lines running to the actuators or to the PCM valve, boost is out of control.

Am I right with this??
 

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I assume you driven the car again since switching it off?

Mine would do this sometimes but would reset after switching the ignition off
 

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Discussion Starter #7
I assume you driven the car again since switching it off?

Mine would do this sometimes but would reset after switching the ignition off
No, as it's just used as weekend toy. But I disconnected the battery in case the ECU has switched in a kind of "safe mode".

Will check IC piping, actuators (perhaps they got stuck) and reconnect the battery next weekend. Then I'll keep fingers crossed and do a test drive and perhaps everything works fine again :nervous:

Does your Engine check light up when this happens or not???

Mine didn't.
 

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Its funny mine never goes above 0.6 bar either and i also took my restrictor out, (doesnt bother me too much mind). thought it might just be tired actuators and i'll deal with it when i get new turbos? but id be interested to find out what you discover buddy!
;)
bob
 

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Discussion Starter #9
Hi Bob,

The curious thing is that, after I had taken out the restrictor it was running 1 bar all day long without any issues:nervous:

I also thought that perhaps the PCM valve doesn't get any power, as this will also limit boost to 0.6 bar...

... but I'll post the solution as soon as I've figured it out mate :thumbsup:
 

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Nice one fella, appreciate it!
:thumbsup:
bob
 

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Discussion Starter #11
@Bob

I wasn't able to do a test drive so far as it was always raining or snowing and f...ing cold since our last chat.

Car gets now a complete service and check up, a HKS EVC and a Haltech Platinum Pro ECU during the winter break, so hopefully the boost problem will resolve with these mods.

I'll let you know if I come across anything that could be responsible for the boost drop.

Cheers

Leo
 

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Nice one Leo buddy, hope your Christmas present list for your car sorts it all out! ;)
Keep me informed fella and have a good one.
:thumbsup:
bob
 

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Be careful fella same thing happened to me and in the end my front turbo shat itself and got thrown into my engine, goodbye engine.
 

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Discussion Starter #15
Thanks for the info mate:thumbsup:

How many miles had your engine done when this happened???

I checked both turbos before I removed the restrictor, there was almost no play in the shafts (especially for journal bearing turbos) and both of them looked pretty good.

But I'll check them again during the winter break.
 

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Mine had done 60k and i had taken the restricter out aswell used to boost like a rocket then all of a sudden wouldnt boost above 0.6 bar altho it got to that pressure fast but wouldnt go higher. If i turned the engine off and came back about an hour later it was fine boost right to 1 bar no probs, couldnt fathom it out so i put it down to the cold damp weather we were having then one day i was revving the car to about 5500 rpm( not even as much as i would rev it to whilst driving) then BANG half the turbo went down the exhaust half went in the exhaust ports:eek:

P.S did you ever solve the boost problem?
 

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I had something similar a couple of days after i first got the car, the first garage I went to try to say that one of the turbos was knackered and would need replacing or rebuilding, I then took the car to an experienced GTR tuner and within 30 minutes they had found a leaking hose and fixed the problem, so definately get all hoses checked.
 

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No, not yet. My GTR hibernates now in my Garage...

Will get back to it in spring after a full service/checkup and some minor mods like an EVC and a Haltech Platinum Pro.

Leo
Heard very good things about the new Haltech platinums, but I think you should save your money on the boost controller and leave it to the Haltech + boost control solenoid :)
 
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