I think I know what this noise is, but....

[Matt McClung]

I just purchased an 86' Gn and I now know the difference between intercooled and non intercooled. I recently lost my 1984 gn in a fire at the shop that it was at, but I used the insurance money to buy the 86'. Anyway, the car is in supurb shape and it is solid and very fast, but when I release the throttle under boost I hear a flapping/slapping noise. It only does it after boost and it wont do it if I realease the throttle slowly after boost, it only does it if I take my foot off the throttle quickly. I personally think that it is the wastegate, maybe the solenoid is bad or the rod is loose. BTW it builds boost just fine. I have not looked myself yet just thought I could pick some brains out here.

Thanks

Matt

 

[441120]

You are correct, that noise is the waste gate.
Sorry about the '84, hope no one was hurt.
Now you see all the fuss about intercoolers :biggrin:

 

[Matt McClung]

Nobody was hurt, but I was crying when I rushed to the shop to see it going up in flames.

 

[Matt McClung]

I was just thinking, I know it is the wastegate flapping but what do you think is causing it? Is the rod loose or is the solenoid bad.

Thanks

Matt

 

[URSPANKED]

Are you pretty sure that it's not the usual noise of the boost escaping through the air filter when you let off the gas? It makes a sound real similar to what you describe. There's nowhere else for the air to go. I really don't think it's the wastegate.

 

[Squid4life]

the noise is just typical turbo sneeze, or flutter, or whatever you want to call it. basically the boost has no where to go and kind of throws the turbo into reverse when you lift. not good to do it all the time, but it is normal for an IC'ed car.