So much for that idea.

ChuckJ
PS did they replace your muffler under the recall?

 

I never received a recall notice about a muffler. Can you elaborate as to which muffler was subject to a recall? I eliminated my center muffler when I had the AWE Performance exhaust installed.

 

It only affected certain build dates, from 3/12 to 11/12. Here is article.

http://www.9magazine.com/2012-2013-p...t-pipe-defect/

 

That's very frustrating that you were able to show the dealer the noise and they said, yeah that's fine.

That's what I'm afraid of, that it's some sort of cam/valve noise inside the engine which will be way more complicated to diagnose and fix.

I was wondering if it was something in the PDK box. What are those things called in a manual gearbox that make sure 2nd gear 'meshes' okay into 1st gear? I used to be able to hear that mechanical rattle type noise in my manual Cayman. I was wondering if it had something to do with that.

 

Early 3.4s had a recall and got both mufflers under the fenders replaced.
2012-2013 YM
Vin range ....06073-06691
.....40074-40635
.....06062-06800
.....40061-40816

The exhaust tailpipe of the rear muffler can fracture and separate.

Your dealer should know if your car is part of the recall. Mine was and it was a May 2012 build.


ChuckJ

 

I will check the VIN, but my car was an August 2013 build date so I am probably not affected.

 

Good info thanks Frank, I'm going to try to confirm these today. I'm not sure if I would rule out exhaust, since the harmonic only happens during acceleration (in my case light acceleration). That would seem to rule out pure rotational harmonics, yes?

If the problem doesn't happen in neutral it sounds like a car will need to be put on a dyno to identify the vibrating element.

 

I think you are referring to "synchros". I don't believe they exist in the PDK. The whole concept of dual clutch would eliminate the need for them.

 

PS mine is a 2014 with only 2k miles so I think it's unrelated to the exhaust recall or any exhaust parts fracturing.

 

First, I am not so sure it is only under light acceleration. If you listen carefully, you will hear it under heavier throttle inputs. Its sounds different because its a shorter interval that rpm's remain in the 3200-3300 range. Second, I am pretty convinced its not harmonic for a lot of reasons. The primary reason is that there is no engine roughness when you stay in the vibration zone. Its just noise. There are a number of possibilities but one that sticks with me is auto tension timing chain. The chain tightens and loosens to adjust the timing under different power requirements. It may be responsible for the metallic vibration sound at a specific timing setting. I think that because it happens in the same RPM range in every gear (gear 1 is hard to hear but it is there) it must be engine related. This sound is so tin like, that it probably isn't bottom engine but rather top engine. For a loud as it is, one would expect to feel it but I don't feel anything, I just hear it. Its the craziest thing.

 

I wonder why it doesn't happen in neutral.

I get it most noticeably in 2nd and 3rd.

 

That's exactly what I was thinking of - synchros. Good to know PDK doesn't have them (my bad) so that wouldn't be it.

I wonder why the noise is unique to the 3.4 and not the 3.8.

 

If someone would voluntarily load their car on to a plane and crash it then I'm sure Greg Feith would be able to figure out the problem. He can figure out anything.

 

I have been doing more research on the vibration issues discussed herein. Since we use the Boxter 3.4 engine I started reviewing threads from various boards. It appears that the problem is known to exist in the Boxster as well. While different solutions worked for different folks, the more common solution was replacing the dual mass flywheel. Now that I think about it, the noise vibration sounds a lot like the turning of the flywheel when it is not attached to the trans. I am not sure how our car is setup with the PDK, but I assume we have one flywheel.

 

Either my C2 does not have the problem or I am unable to detect it. Just shy of 40,000 miles and it's smoother and more powerful today than when i bought it in June 2012