Cabin Resonance

Hi, This is my first post, so HELLO to all my fellow Cayman owners... I have owned my used 2007 Cayman for just 4 days. I purchased it in Dallas and drove it back to Arizona the same day in some of the worst weather I have seen. It is a testament to this car that I am alive after pushing through serious rainstorms for over 15 hours at 80mph, mostly at night. The trip was 1095 miles of getting to know my new car... I love, love, love the car except for one thing, the resonance in the cabin at specific RPM/SPEED combinations. I have a Tiptronic transmission and the worse time for the resonance seems to be if the car is in 5th and I am going about 50 mph. If I am going up a slight hill it gets much worse, if I am going down a slight hill it seems to almost disappear..! So the question to all of you is… is there anything I can do about this? Is this the exhaust system causing the noise or is there some other source of this issue. Thank you in advance for any help or advise on this issue… Chris

Change Gear............

Does your car have an aftermarket exhaust, or factory exhaust?

Gator Bite, I believe that the exhaust is stock. I looked at pictures of the stock system on this forum and is looks like it, as far as I can tell.. Chris

Seeing that the car is still in warranty you might be better off taking it to a dealer and getting everything checked out if you didn't get the recommended pre-purchase inspection at a dealer done. Even if you did it would be worth a more specific look if this bothers you. It could be related to a number of things. Good luck.

I get a strange buffeting sensation at 2000 rpm. Think it might be to do with the rear hatch!

Santa Fe, I did even more than that, I had the car certified by Park Place Porsche before I picked it up...! I now have a 4 year 100k mile warranty on the car. This is a dream car for me and I would like this one thing resolved with the car. Other than this one thing the car is everything I hoped that it would be. Chris

You didn't mention the rpm range. As a guess I say somewhere around 2500-2800 rpm. Same as my '08 exhibits a resonance/drone with stock exhaust in 6th gear. I wonder if this is similar to the drone some complain of with aftermarket exhausts but to a lesser degree? A downshift gets one out of this as mentioned.

Chris, you seem like a pretty careful person so consider this brainstorming not advice. But before you take it to a dealer see if you can get a couple of more people to hear what you hear to help define the source and the description of the sound. Then before getting to the door of the dealership find a nearby road where you can replicate what you all hear. Take the service person with you to that locale and demonstrate the sound. That way you will be less likely to get one of those " could not replicate " service tickets. Also see: http://www.planet-9.com/cayman-complaints/2550-heat-shield-resonance.html and http://www.planet-9.com/cayman-complaints/16359-resonance-rpms-fall-through-

Taggarc - It sounds like you are describing what some call the trunk boom (not clunk which is another problem). I had the same problem more like a low frequeny pressure oscillation than a resonance, it disappears when you open the windows. The fix for me was to tighten the rear hatch by adjusting the latch - night and day difference. Search the site there are instructions on how to tighten it - it takes literally five minutes.

Thanks for that Shellshocked will give it a try over the weekend and see whether it results in a cure.

ChrisL, If what you are hearing is a very low frequency resonance, check the rear hatch stoppers on either side of the hatch lid. Unscrew them a half turn at a time until the hatch becomes harder to close. I found that my rear hatch would vibrate at some speeds, especially in the 40-55 mph range. Adjusting the hatch bumper stops made a huge improvement!

Interesting. I took a PDK Cayman for a test drive this week and found the harmonics in the cab really annoying after about an hour. I was more than happy to get back in my 2006 Boxster S afterwards

Though this is not a problem I have never experienced with my Cayman, here is the solution: The frequency where the resonance occurs is determined by, among other things, the volume of the interior cabin. So, if you change the volume, you can move the resonance to another frequency where it is less annoying. This can easily be done in two ways: 1. Take it to the dealer, and have them raise the roof a couple of inches, thus increasing the interior volume. 2. Get a very fat girlfriend to sit in the passenger seat.

"Get a fat girlfreind." O ho ho. Okay, I noticed the resonance, too, after ordering the car and waiting two long months, then driving it home. I wondered if I had made a horrendous mistake. There is a certain cabin pressure that sets the Cayman apart. In an earler post, one new buyer said it almost made him sick to his stomach. If you're like me, you will adjust after 2 weeks, or less. I've had my CS for two years now and LOVE it--don't even notice the resonance anymore. To make the transition easier, crack a window an inch or so. That will alleviate the pressue until you get used to it.