Stock turbo N54 with new VTT wastegates, still rattling

JonEQuest · 02-26-2020, 12:42 PM

Quote:

Originally Posted by e90 Second Incarnate

Well OP if the car is running correctly now, boosting well, I’d still ask the shop how they adjusted the wastegates after fixing them. They should be clear with you that they set them up on the bench using a specified level of vacuum, before installing them in the car.

I rebuilt my N54 and had no experience with these engines... But I had heard about how much of a problem they had with wastegate rattle. So when they were pulled from the car while I was replacing the head gasket I adjusted them to the vacuum that was suggested by some YouTube video. After that I put them back on and have never had any rattle. These are stock 75k mile turbos that had fairly loose worn parts. It is all about the proper vacuum pulling them in at the right time.

type-dRew · 02-26-2020, 01:02 PM

Quote:

Originally Posted by JonEQuest

I rebuilt my N54 and had no experience with these engines... But I had heard about how much of a problem they had with wastegate rattle. So when they were pulled from the car while I was replacing the head gasket I adjusted them to the vacuum that was suggested by some YouTube video. After that I put them back on and have never had any rattle. These are stock 75k mile turbos that had fairly loose worn parts. It is all about the proper vacuum pulling them in at the right time.

Link?

e90 Second Incarnate · 02-26-2020, 03:45 PM

Well technically, I think that the specified vacuum will pull the actuator all the way. With the actuator pulled all the way, the linkage needs to be adjusted so the flapper valve is firm up against its seat. As the linkage and shaft continue to wear, it will no longer seat firmly, and will start to rattle again. Rinse and repeat. I suppose you could adjust it extra tight, to anticipate further wear and increase the adjustment interval, but not sure if this may damage the actuator or change the wastegate performance.

JonEQuest · 04-02-2020, 05:21 PM

Quote:

Originally Posted by type-dRew

Quote:

Originally Posted by JonEQuest

I rebuilt my N54 and had no experience with these engines... But I had heard about how much of a problem they had with wastegate rattle. So when they were pulled from the car while I was replacing the head gasket I adjusted them to the vacuum that was suggested by some YouTube video. After that I put them back on and have never had any rattle. These are stock 75k mile turbos that had fairly loose worn parts. It is all about the proper vacuum pulling them in at the right time.

Link?

I am not sure which video. It has been a while but search for "N54 wastegate rattle" or "N54 wastegate adjust" etc a D you will find it. It is a guy who rebuilds turbos showing how he rewelds wastegates and then how to set them. I think it was something like closed at 6 or 7 hg of vacuum. I have had a vacuum tester with gauge for years and finally got my monies worth out of it.

02-26-2020, 03:45 PM	#25
e90 Second Incarnate Enlisted Member 8 Rep 35 Posts Drives: 2008 335i Join Date: Jan 2020 Location: SF Bay Area, California iTrader: (0)	Well technically, I think that the specified vacuum will pull the actuator all the way. With the actuator pulled all the way, the linkage needs to be adjusted so the flapper valve is firm up against its seat. As the linkage and shaft continue to wear, it will no longer seat firmly, and will start to rattle again. Rinse and repeat. I suppose you could adjust it extra tight, to anticipate further wear and increase the adjustment interval, but not sure if this may damage the actuator or change the wastegate performance. __________________ 2008 335i 6MT FBO 2009 Tacoma TRD Sport A whole quiver of motorcycles, dirt and street, vintage and modern
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