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Discussion Starter #1
I've been having some problems with my 2006 Cayman S being "lurchy" during starts and sometimes it felt like it was slipping under acceleration. I thought it might be a misfire or a problem with the clutch, but both turned out to be dead ends.

One day while my wife and I were driving back from a Dine and Drive with the PCA, we were on the highway and I was driving in traffic I was noticing that I was getting a slip/bang feeling when I applied the throttle after letting off for a bit when traffic slowed ahead. I recognized this as similar to when I broke the front differential mounts on my FC3S RX-7 several years ago. It was a feeling like the driveshaft was using some of the torque to move the differential and then a thump when the differential hit the bottom of the floor.

Since the Cayman, being mid-engined has none of these, and I know my driveshafts are fine, I turned my attention to the rest of the drivetrain to try to figure out what it could be. The only other reasonable explanation is that my dual-mass flywheel is offering no resistance and so is moving it's full length of travel and that is the "slip" and "bang" feeling and it's been getting progressively worse. I did a search of the posts and found someone describing the same issue and that the dual mass flywheel was about to fail.

I guess my question is: Is it okay to drive it like this or is there a possibility for catastrophic failure? It's been getting worse and worse since I figured out what it is, and so I have been driving the car minimally, about every two weeks just to keep the battery charged, but we have some upcoming PCA events (non-performance, just drives and shows) and I want to know if it's safe to take the car or whether I just need to park it while I save up for the repair.

Yes, I'd like to procrastinate this one if I can, because I've priced out the Flywheel and the clutch kit (since you might as well do it while you're in there) and the $$$ is racking up, and because of my back problems, I'm not sure I could DIY this myself in my driveway on jackstands.

Any input would be greatly appreciated. I haven't found a lot of information regarding what happens when these fail.

Also, has anyone had ANY issues crop up with going with a lightweight flywheel in place of the OEM Dual Mass unit?

Thanks
 

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If you are a member of PCA and are on the Cayman Register, Gator Bite has an excellent technical post about the DMFs in our car. Check it out.

If your problem is indeed the DMF, I don't think a catastrophic failure is a risk. You will, however, get vibration and gear clatter because the DMF is not doing its job. Incidentally, this is why a lightweight flywheel is a bad choice for the Cayman, unless it's a dedicated track car.

I do question that the DMF is the source of your problem. The "slip-bang" feeling doesn't sound like the right symptom. You mentioned that a clutch problem was a "dead end" - how so? Did you remove and inspect it? To me a failing clutch is the most likely cause of your issue.

Time to have your indy shop pull the tranny and have a look in there. Good luck and keep us posted on your progress.
 

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Discussion Starter #3
If you are a member of PCA and are on the Cayman Register, Gator Bite has an excellent technical post about the DMFs in our car. Check it out.

If your problem is indeed the DMF, I don't think a catastrophic failure is a risk. You will, however, get vibration and gear clatter because the DMF is not doing its job. Incidentally, this is why a lightweight flywheel is a bad choice for the Cayman, unless it's a dedicated track car.

I do question that the DMF is the source of your problem. The "slip-bang" feeling doesn't sound like the right symptom. You mentioned that a clutch problem was a "dead end" - how so? Did you remove and inspect it? To me a failing clutch is the most likely cause of your issue.

Time to have your indy shop pull the tranny and have a look in there. Good luck and keep us posted on your progress.
I'll check out the article on the Cayman register.

I'm pretty much 98% certain it's not the clutch. I've driven MT cars for 30 years so I'm pretty familiar with what a slipping clutch feels like... and checking for clutch slip basically is to get it up to speed, put it into a higher gear, and go WOT and see if the revs jump. When I try that test with this car, once it "takes up" the slack there is no slippage, which is what is making me think it's the flywheel springs not dampening the dual mass motion.

I guess the "slip-bang" feel was a poor description, it's basically you can feel the car take up when you apply throttle and then it's suddenly engaged once the slack is taken up.
 

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My DMF went out last year. I was getting vibrations. I installed the SMF. Noisy (lots of gear rattle).
 

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I had a 2006 VW TDI with DSG and the DMF started wrattling around 80k miles. There have been situations in VW's where the failing DMF broke apart and fractured the transmission and or engine case. VW uses the same brand of DMF as Porsche it'a Sach's. Go to youtube and enter VW dual mass flywheel and several dozen videos will appear. There is even a video that shows the transmission case fractured with pieces missing due to DMF breakup. DMF breakup is probably a rare situation if the DMF is changed when it begins to make noise.
 

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Discussion Starter #6
So far I haven't noticed it making noise yet, but I also have a Borla exhaust so I wouldn't hear anything subtle yet. Right now I can just mostly feel it.

Yeah, I know that both VW and Porsche use the same Sachs DMF so thanks for the heads up on the problems that VW had. I have about 64K on my Cayman.

Based on the input so far, it sounds like the lightweight flywheel isn't suited for daily driving, and it sounds like I need to listen for noise to know when it's starting to get bad.

Thanks everyone for the input so far.
 

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If you search, you'll find the diagnostic procedure to check if a DMF is functioning properly.
 
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