930 engine click/crack
 

Hello

I have a 1987 930 coupe that is completely stock. It starts, idles and runs great.

I have begun hearing a click or crack type sound that is either coming from the intercooler duct work or under the intercooler itself. The sound reminds me of the sound of 2 pieces of metal slapping together quickly, the sound of a high voltage spark, a .22 breaking the sound barrier, or maybe even a whip crack.

It occurs all of the time with a cold or warm engine. With the car out of gear I can slowly increase RPM w/o hearing the sound. If I stab the throttle I instantly hear the sound either from idle speed or if I slowly increase the RPM to 2000 and then stab it. There is only 1 crack that occurs until I release the throttle and rev the engine again.

When driving I hear the sound whenever it is in gear with the clutch out and I release the throttle to coast. As soon as I even slightly press on the throttle I hear the crack. Again there is only one crack that occurs until I release and press on the throttle again. If I coast with the clutch in I can slowly increase RPM w/o hearing the sound. If I stab the throttle with the clutch in I again hear the crack.

I suspect that I am hearing the waste gate slapping shut. I have great boost and the factory boost gauge goes all the way to 1.

Is this something I should be concerned with, and how difficult will the fix be.

This should help you out: http://forums.pelicanparts.com/porsche-911-technical-forum/71370-changing-930-dump-gaskets-pictures-galore.html

Yep, that's it. Think of it this way: It will make that noise everytime the engine makes the transition from vacuum to no vacuum (on and off the throttle, basically). It will actuate the boost recirculation valve/piston.
Not to worry, she's not about to blow up!