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Discussion Starter · #1 ·
Hi there.. I picked up a GTR today.. was driving it home generally taking it easy.. after a bit I decided to open it up a little.. It's on standard turbo's and the boost is set to 0.9bar as far as I know.. (which I gather is the max for standard turbos?) when I accelerated the boost gauge went up to 0.9bar then after a couple of seconds it dropped back to 0.6bar or just over.. After this the boost wouldn't come up to 0.9 again.. and the max I could get was 0.65.. any ideas?? a leak some where?? I also thought it felt flat if you put your foot hard down?? you could feel it being a little sluggish.. you had to lift off and ease the throttle on..
There is no smoke or anything and it sounds perfect so I don't think one of te turbo' has blown.. plus it was only doing about 4500pm!

Some one please give me soem ideas..

Cheers
Lee
 

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In the worst case a turbine wheel has snapped. And the dont just snap of high rpm but of torque aplied to the wheel also. Maybe the actuator is stuck open? try to disconnect the vacuum hose of each turbo individualy one at a time and both at the same time. You should be able to detect if one turbo is not working properly.
 

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If you are using a boost controller, then it may have detected overboost dependant on the value set, and has gone back to baseline mode.

But then again, it should have been normal again after a certain time, or at least once you've switched off and restarted the car.
 

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Discussion Starter · #4 ·
cheers Guy's I will have to check the turbo's out... I guess.. BUt would there not be smoke from them if one had gone west? And I presume the boost would drop to 0.45 if one turbo wasn't working??

I don't know if there is a boost control?? cetainly nothing in the car? Haven't been under the bonnet too much..

Don't think it's lkely it just a leak then?

Bugger!!

Merry Christmas all..
 

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hmmm

I was testin last night and i didnt get over 1.0 bar boost ?
I got Nismo N1 turbos and HKS evc (very old model)

I try manual mode of evc and turn it full boost but 1.0 is max what it makes ?

Car is running quite rich on full throtle. AF about 10.2
 

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cheers Guy's I will have to check the turbo's out... I guess.. BUt would there not be smoke from them if one had gone west? And I presume the boost would drop to 0.45 if one turbo wasn't working??

I don't know if there is a boost control?? cetainly nothing in the car? Haven't been under the bonnet too much..

Don't think it's lkely it just a leak then?

Bugger!!

Merry Christmas all..
I doubt there is anything wrong with your turbo's, it sounds more likely that you car is running a standard Nissan boost control solenoid that has been "kidded" into running higher boost. Check the cylidrical valve (32mm dia x 70mm long approx with 3 black rubber pipes running to/from it) located on the front side of the drivers side inner wing, just behind the battery, if this has a Nissan part no. sticker on it, it is a std. item. This is a problem I suffered with my GT-R, I think that the restrictor in the actuator line had been drilled or removed making the boost reach a higher maximum. This, unfortunately is highly unreliable method of increasing boost pressure, you may run 0.9-1bar boost sometimes but the std valve cannot hold this as a reliable constant, this is what looks like is happening with your GT-R (I lost a turbo because of it, massive overboost on cold morning). I replaced the std. item with a GReddy Profec B spec II electronic boost controller set-up and have never had a minutes bother since, readilly available and quite an easy DIY install. I now run 1.01bar boost max, all day every day. :thumbsup:

Definately worth checking out if you have an issue with this, if you are unsure yourself, have one of the many reputable tuners/garages have a look for you, it will be cheaper in the long run. ;)

Do a search on here also, you will see many threads and opinions on the subject.

Hope this helps.
 
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