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Discussion Starter #1
I have just completed a turbo upgrade to my R33 GTR. I replaced the standard turbos with a pair of Garrett 2860 -7. This was an enormously fiddly task but I'm quite satisfied with the end result. When I took the car for its drive with the newly fitted turbos, I noticed as the turbos came onto boost I could hear a loud whistle coming from what sounded like the rear turbo! Maybe the turbo had faulty bearings?
A little bit of research on the net indicated that most likely the whistle was air escaping somewhere in the engine induction side when boost came on. I did a quick test of all pipe clamps and nuts/bolts on the turbo induction side, they all look like they were done up nice and tight. Further net research showed various boost leak tester to help locate where a leak might be.

Engine Bay
Nicely fitted new turbos and reassembled components – but with a boost pressure leak!



Tools of Trade
I disassembled the intake pipes and worked out I needed 3 plugs to seal the intake side. I have shown the various ‘tools of trade’ (plugs) I used, anything you can find will work – all you need is a nice seal. I only had to purchase a length of 2.5inch silicon tube. ($20 at SuperPro). I used an empty can of baked beans but have since sourced a better seal. An oil filter number Z468 I use on my magna is a little bigger and provides a better seal than the baked beans.



Plugs Fitted
The next 2 pictures show how the pipes and plugs were attached to seal the engine intake side.





With these 3 plugs and pipes fitted the entire engine intake is sealed and is now able to be pressurized to check for leaks. The hair product can and silicon/paint can provided a 100% seal, whereas the baked beans can was not quite perfect, but did allow me to pressurize the engine intake and check for leaks.

Pressure to the Intake
I worked out I could pressurize the intake side by applying pressure from a portable air compressor to the pipe attached to the standard boost controller. There are 2 pipes attached to the standard boost controller, one goes to the pipe where the rocker cover breathes, and the other is attached under the plenum that is boosted from the turbos. This is the pipe to use.



I fired up the air compressor and attached the hand trigger to the pipe as shown above. I set the compressor output somewhere between 5 and 10 psi. Instantly I could hear air escaping somewhere near the rear turbo. I was not able to see any pressure on the gauge.

Suspect Found
I filled a plastic spray bottle with dishwashing soap and water and coved the offending turbo with water and soap. Instantly I could see bubbles exiting from the rear turbo output flange.



I doubled checked all bolts were nice and tight, however when I loosened the top bolt, the the pipe could move slightly! Further investigation revealed the bolt was bottoming in the thread and not applying sufficient torque to the pipe flange, thus allowing air to leak under pressure.
I removed the flange, located a slightly shorter bolt, refitted everything and applied pressure. I could now see pressure holding on the gauge and with the trigger released, the engine intake would now hold 5 to 10 psi and over a minute or two the pressure slowly fell. I used the water and soap again and covered various components. I noticed air leaking around the baked beans can and also some leaking around a boost controller I had fitted. These were tightened, however I was not able to seal the baked beans can.

Suspect Gasket
Below is a photo of the output flange gasket with a bit missing. My bet is somehow I damaged it when assembling the ouput flange and the piece dropped into the threaded section preventing the bolt from pulling up properly.



All OK
I refitted all the intake pipes again (I am quick at it now), went for a spin and everything appears fine. This method certainly allowed me to find my boost leak and it tests the complete intake side from the input to the turbos to the manifold butterflys.
I would be interested if anyone else has found an easier method for the the GTRs.
 

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This will come handy. Just came back from the harbour port where I picked up my GT-R. At halfway back home (around +300km...) I started hearing a wooshing noise during heavy boost and the noise increased and increased while the threshold dropped down to just barely positive pressure (like 0,01 bar) and the last 100km or so I had to drive uphills at about 60km/h to avoid a noisy fluttering & wooshing sound and black smoke from my exhaust. So it's now 2:21 AM and I can go to sleep knowing I have the tools ready to tackle the job tomorrow ;) What a day...
 

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Discussion Starter #3
For my next Boost Leak Tester I plan remove the air cleaner with the air flow meters attached. This will leave just 2 pipes about 65mm to plug up. The same process of pressuring the intake manifold can then be done.
I have a Mitsubishi 3.5 litre Magna (Diamante) and I have noticed the oil filters are about 68mm outside diameter. I have saved a couple of Z456s and plan to try these soon.

Search Part : Ryco Oil Filter | Z456 Oil Filter | MITSUBISHI MAGNA :: Ryco Filters :: Automotive Filters Australia

Cheers
 
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