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Today at Atelier Kaz - Private NSX Enthusiast, ex-Honda R&D engineer with F1, Indy/CART background

CAT & Exh. area noise revisited... Part 2

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As pointed out to the owner last time, it was possible that the noise was coming from the cracked welding at the exh. bracket.


So, to test it, I applied high temp non-melting grease into the cracked section.


It made some difference but still some noise was there.




There were two exh pipes with only about 2mm gap at the rear left side of the aftermarket exhaust but even when they were hot or cold, they were not touching each other and it was shown to the owner while the car was on the lift.





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Then, inspected the exhaust hangers and found that one of the rear left one was very dry and making squeaking noise when moved.


Not sure whether this was the cause of the noise but to be on the safe side, applied high temp water proof grease on all four hangers.


The one at the Front down pipe/CAT area was already treated last time.



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It was also possible that the heat shield at the Rear CAT started to make some noise as all of the fixings were completely corroded.


Didn’t want to make too many changes in one go so decided to leave it this time.


For the test driving session, we agreed to use the motor way so I drove for two junctions and then got off the motorway, stayed at the slip road to simulate the short thermal shock, back on the motor way for another two junctions and left the motor way.


Then, stayed at the local car park for a while to simulate the heat soak before making my way back to my place.


On the way back, the window was kept open.


Once back at my place, kept the engine running for 20min and then placed it back on the lift.


As same as last time, there was no noise after the test driving session.


Even before the owner reported the noise, this car passed the test driving session for two times.

Once after the TB service and 2nd time after the recent service.


So, not sure why the noise didn't happen after two driving session ...


As I couldn’t pin point the cause of the noise, I decided not to charge the owner for the service carried out this time.



The owner collected his NSX now so looking forward to hearing from him later.


Kaz
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