Hi guys, I've seen wastegate flutter issues posted many times, and I've replied to several. I have a fix for this that I posted on nabisco a long time ago, so I guess its time for it to be posted here. Here we go:

The annoying wastegate flutter that many people experience, especially with aftermarket downpipes, is caused by the wastegate opening slightly at part throttle boost (0-7psi). With an aftermarket downpipe, there is much less backpressure helping to keep the wastegate closed, and so the flutter becomes signficantly louder. It usually happens at part throttle conditions with very little boost and sounds like a rapid ticking sound... its sometimes mistaken for detonation.

The solution is to adjust the wastegate actuator arm slightly, effectively putting a very slight pre-load on the wastegate spring to help keep it closed at part throttle boost. This procedure will not eliminate the flutter completely, but it will come very close.



First take off your turbo heat sheild (there are 4 or 5 bolts holding it on. Next you will need to pop off the C-clip pictured. Disconnect the wastegate arm from the wastegate, and unscrew the lock nut. Then shorten the arm 1-3 turns, re-assemble everything and go for a drive.

The key here is the number of turns. You want the arm to have only a very slight pre-load when you attatch it back to the wastegate. If you turn it too much, you will experience boost spiking especially at part throttle. If this happens, back it off 1-1.5 turns and you should be good to go.


For more information, visit: http://forums.nasioc.com/forums/showthread.php?t=425018 -- 12 pages!

Thanks
-- Ed