Clutch upgrade

[Ziff]

Anyone upgrade their clutch yet? I have experienced an intermittent clutch slip and decided to replace my clutch and flywheel with an upgraded package from AWE that includes a lightweight flywheel. Anyone have any feedback or experience with an upgraded clutch/flywheel package?

I received the package last week, but have not had it installed yet. I noticed that the clutch disk is a non-spring type and before I install it, I wanted to get some feedback from some users. The clutch package from AWE is the Sachs Stage 2.5 Clutch Kit - With Flywheel.

Thanks,

Walt

[JFP in PA]

Anyone upgrade their clutch yet? I have experienced an intermittent clutch slip and decided to replace my clutch and flywheel with an upgraded package from AWE that includes a lightweight flywheel. Anyone have any feedback or experience with an upgraded clutch/flywheel package?

I received the package last week, but have not had it installed yet. I noticed that the clutch disk is a non-spring type and before I install it, I wanted to get some feedback from some users. The clutch package from AWE is the Sachs Stage 2.5 Clutch Kit - With Flywheel.

Thanks,

Walt

Be aware that moving from a dual mass to a single mass flywheel is not recommended on non-Metzger engine cars without internally rebalancing the engine to dampen harmonics. The dual mass flywheel is the only harmonic dampener in the engine and its removal has caused some pretty significant problems, including crank failures. Jake Raby has written extensively about these problems on his website: http://www.flat6innovations.com/index.php/broken-crank Porsche also once circulated an internal memo to dealers telling them that they would not honor engine failure warranties on cars that had been switched to single mass flywheels for the same reasons.

Single mass flywheels and unsprung clutch discs also can be a noisy pain to drive on the street.

[Ziff]

JFP,

Thank you! That was exactly the feedback I was hoping to receive, however the reference in your response says "....on non-Metzger engines...." and unless I am mistaken, my 2008 GT2 is one of the best of the last of the Metzger engines.

Regardless, I am not going to install the LWFW and unsprung clutch as you confimered that it would be a noisy pain on the street which I don't want.

It is my understanding that my 2008 GT2 motor and the motor in the 2011 GT2RS share most of the same parts, however I read that the GT2 RS does have a single mass flywheel whereas my 08 GT2 has a dual mass. I am inclined to keep the factory stock dual mass flywheel and I am now considering the SPEC Stage 2 clutch kit part number SPC-SP842 which retains a sprung hub clutch, but with a higher torque rating. Information on this upgrade cluch kit is listed on Pelican Parts and seems like the right option for me. Thoughts??

Thank you in advance for your time, insight, and feedback.

Walt

[JFP in PA]

JFP,

Thank you! That was exactly the feedback I was hoping to receive, however the reference in your response says "....on non-Metzger engines...." and unless I am mistaken, my 2008 GT2 is one of the best of the last of the Metzger engines.

Regardless, I am not going to install the LWFW and unsprung clutch as you confimered that it would be a noisy pain on the street which I don't want.

It is my understanding that my 2008 GT2 motor and the motor in the 2011 GT2RS share most of the same parts, however I read that the GT2 RS does have a single mass flywheel whereas my 08 GT2 has a dual mass. I am inclined to keep the factory stock dual mass flywheel and I am now considering the SPEC Stage 2 clutch kit part number SPC-SP842 which retains a sprung hub clutch, but with a higher torque rating. Information on this upgrade cluch kit is listed on Pelican Parts and seems like the right option for me. Thoughts??

Thank you in advance for your time, insight, and feedback.

Walt

I think your second choice is a good one, it offers higher clamping force but should retain better drivability on the street. Some tend to forget about why most street discs are sprung; they "soften" the take up on the drive line as you first pull away, and at every gear change. On a race car, no one cares about clutch chatter and increased driveline noise, you only car about how fast and how durable the system is. But on the street, it ain't always about how fast; sometimes you want to turn on the air, crank up some tunes, and drive somewhere comfortably without having the fillings shaken out of your teeth when you pull away from every stop light.

The major difference in this area when looking at a Metzger vs. a non Metzger comes into play both in components and engine assembly technique. The Metzger engines use a true forged steel crank, which is much stronger than the non Metzger's have, so they can stand up better to the harmonics. If you saw a Metzger crank out of the engine case and tapped it with a metal object, it would ring like a bell. The nodular iron crank would make a clunking sound when you did the same thing. Two different worlds. Secondly, the Metzger engines are also fully internally balanced, which reduces dramatically the harmonic stresses on the rotating assembly. You are also correct in that the RS (and the RSR) units have a single mass flywheel, which was also balanced with the engine assembly from the factory, as they were designed to be more a race car that happens to be on the street, and can get away with less dampening for the reasons I mentioned. It is also why some notice that a Metzger car seems smoother than a non Metzger car; it actually is, but for some very expensive reasons.

[Loren]

Been there done that.... :o :lol: :rolleyes: but I was much younger then...

I agree - the second choice is the sensible one.

[Ziff]

Thanks guys. I was told that the stock clutch disc is not a sprung hub, which is surprising. The shop that is going to do the work is recommending the Porsche Motorsport clutch kit and I am being told the disk is unsprung. I told them to show me the stock clutch and pressure plate before installing a new one. I just want the stock like pedal feel and engagement with a clutch that has a higher rating than stock. You would think this would be easy, but apparently it is not.

Any other GT2 owners care to weight in on this topic?

[JFP in PA]

Thanks guys. I was told that the stock clutch disc is not a sprung hub, which is surprising. The shop that is going to do the work is recommending the Porsche Motorsport clutch kit and I am being told the disk is unsprung. I told them to show me the stock clutch and pressure plate before installing a new one. I just want the stock like pedal feel and engagement with a clutch that has a higher rating than stock. You would think this would be easy, but apparently it is not.

Any other GT2 owners care to weight in on this topic?

I'm not so sure about that, this is the OEM Porsche clutch kit for your car:

There are several aftermarket discs that are available unsprung:

And even some multiple disc setups as well:

But your factory clutch disc should be sprung............ Your car is a GT2 correct, not an RS car?

[Ziff]

Yes, a 2008 GT2. The photos are the ones I viewed on the EVOMs website. The middle photo appears to be the Stage 1 Dual Mass - Sport Clutch Kit and it appears to be unsprung. Since the photos don't seem to match up on the site, I will give them a call. The shop I am using is ordering a Porsche Motorsports clutch, but I can't find any information on it. This is getting very annoying.

Thanks for your help JFP.

[Ziff]

OK, now I think I got it figured out. I spoke with Mike at AWE tuning this morning and he confirmed that the GT2 stock clutch is a sprung hub. He also confirmed that a Porsche Motorsports clutch is a Sachs racing clutch. The Sachs stage 2.5 kit that I bought will work with either the stock dual mass flywheel or the lightweight single mass. He confirmed that there are no issues with engine balance using their LWFW and the stage 2.5 kit will have a very similar clutch pedal feel, release point, and engagment as the factory GT2 clutch. Even though the clutch hub is unsprung, Mike tells me that the clutch material uses fasteners that have enough give (I believe he referred to them as marchal springs?) that the absence of a sprung hub won't be noticiable. Mike sasys that this kit has been extensively tested and 100s of these kits have been sold by AWE. With this feedback, I am going to have the AWE Stage 2.5 clutch kit installed, however I am still on the fence on the LWFW. I am going to have the technician take a look at the stock flywheel and if it needs to be replaced, I will install the LWFW, otherwise I'm not sure what I will decide.

I will repost when the new clutch is installed. In the meantime, if anyone is using the AWE Stage 2.5 clutch kit with LWFW, it would be great to hear your experiences.

Thanks!

[JFP in PA]

OK, now I think I got it figured out. I spoke with Mike at AWE tuning this morning and he confirmed that the GT2 stock clutch is a sprung hub. He also confirmed that a Porsche Motorsports clutch is a Sachs racing clutch. The Sachs stage 2.5 kit that I bought will work with either the stock dual mass flywheel or the lightweight single mass. He confirmed that there are no issues with engine balance using their LWFW and the stage 2.5 kit will have a very similar clutch pedal feel, release point, and engagment as the factory GT2 clutch. Even though the clutch hub is unsprung, Mike tells me that the clutch material uses fasteners that have enough give (I believe he referred to them as marchal springs?) that the absence of a sprung hub won't be noticiable. Mike sasys that this kit has been extensively tested and 100s of these kits have been sold by AWE. With this feedback, I am going to have the AWE Stage 2.5 clutch kit installed, however I am still on the fence on the LWFW. I am going to have the technician take a look at the stock flywheel and if it needs to be replaced, I will install the LWFW, otherwise I'm not sure what I will decide.

I will repost when the new clutch is installed. In the meantime, if anyone is using the AWE Stage 2.5 clutch kit with LWFW, it would be great to hear your experiences.

Thanks!

Glad you got it sorted. I know Porsche has a Motorsports clutch assembly which fits your car, and uses an un sprung disc, but was under the impression that they normally do not deliver street cars with this assembly in them.

The "marcel" springs he is referring to are in between the two clutch friction material faces:

Most stock and HD clutches have what is called a Marcel spring. This is a wavy flat spring that is bonded to the friction material, and then riveted to the disc itself. You can see it when looking at a clutch disc on its edge. The marcel acts like a cushion, smoothing out the final engagement of the friction material by allowing the clamping forces to build up a little slower. When the clutch is fully engaged, the marcel smashes flat and has no effect. The marcel is removed from racing-type and metallic clutches for two reasons. The marcel prevents the friction material from being 100% bonded to the disc, reducing burst strength and it also increases engagement travel, possibly slowing shifts which is a little harder on the syncro's.

[Ziff]

JFP, thanks for the Marcel spring visual and explanation. You are correct that the unsprung disks are not used in street cars. The picture of the sprung hub clutch is in fact the factory type clutch for the 997 Turbo and GT2 cars.

I am scheduled for the new clutch install on Monday. Will update afterwards. Thanks again!

Walt

[Ziff]

My new clutch and lightweight flywheel are installed and I drove it home tonight. The clutch pedal feels about the same as before and the gear rattle I expected to hear as a result of the LWFW is almost non-existent. I had to push the clutch in and out a couple times until I could hear the difference. Not at all what I expected and very pleasantly surprised. The engagement feels exactly the same and if I didn't know the clutch was upgraded and a LWFW installed, I may not have noticed anything different at all. The only noticible difference is that it revs easier and quicker than before which is what I expected. I asked the mechanic to put the old parts in the new part boxes and place them in the trunk and much to my surprise, the stock clutch is not sprung, it is unsprung, just like the upgraded one I installed. I checked the part number and it is not an aftermarket clutch, it is the stock one and indeed it is unsprung which may explain why the feel of the new clutch is so similar. Perhaps the Turbo clutch is sprung and maybe the Turbo and GT2 share the same flywheel and preasure plate, but unless there was a mix up at the factory, my GT2 was built with an unsprung clutch disc.

I highly recommend this clutch kit with LWFW as packaged as a kit by AWE and a big thanks to Intersport and Omar Hilmi for their great customer service and installation.

http://www.intersportautosales.com/

Walt

[C2cab]

How much life can I expect on the clutch for a 997-1TT? Looking at an '08 with 45K and trying to determine when the next big expenses will occur.

[JFP in PA]

How much life can I expect on the clutch for a 997-1TT? Looking at an '08 with 45K and trying to determine when the next big expenses will occur.

Depends more on the driver's style than the miles; we have seen clutches with 80K on them that looked nearly brand new, and others with 40K on them that were toast.

[Silver_TT]

Definitely agree with JFP that mileage will be a misleading indicator because it matters how the car was driven -- lots of start/stop vs highway as well as generally how hard the car was driven, etc. At 45K though it should at least be on your radar if you're looking to buy the car and need to budget for repairs. I've seen a guy on this site who said he has 300K kilometers on his TT with the original clutch. Maybe he logs a ton of highway miles, I don't know. My 996TT, which has a very similar gearbox to the 997TT manual you're referring to, needed one at 45K. Just depends........

Edited April 28, 2014 by Silver_TT

[Dennis Nicholls]

The Metzger engines use a true forged steel crank, which is much stronger than the non Metzger's have, so they can stand up better to the harmonics. If you saw a Metzger crank out of the engine case and tapped it with a metal object, it would ring like a bell. The nodular iron crank would make a clunking sound when you did the same thing. Two different worlds.

Back when I was rebuilding BMC "A" engines I had a handful of scrap cams to play with. They really would ring like a bell so I made a wind chime out of them. The test for a cracked crank was to hang it on a string and hit it with a hammer. If it rang it was OK, if the sound was muffled it was cracked.

[RPK]

Ziff,

 

Thanks for sharing your SACHS 2.5 clutch upgrade with the lwfw on your GT2.

 

I have a 2009 997 GT2 which is due for a clutch change and am wondering what is your experience with it a year+ down the road? Happy still to recommend the lwfw kit or stick to the dual mass ? Any crankshaft issues running the lwfw?

 

Appreciate your comments...thanks in advance!

[Silver_TT]

Stick with the dual mass for sure. 

 

Read this:

http://flat6innovations.com/index.php/broken-crank

[RPK]

Silver - Thanks for the heads up!

 

Definitely want to avoid any risk to the crankshaft ! Will stick with Dual Mass and just upgrade to the stronger SACHS clutch.

 

I also spoke with a race engineer for a Carerra Cup Asia team earlier today and he said he previously converted a Carerra to single mass , couldn't stand the gear box rattle and changed back to Dual.

[Silver_TT]

Sounds like a prudent plan.  The improved responsiveness gained from switching to a SMFW is more than offset by the fact that you are subjecting yourself to risk.  Gearbox rattle could be the least of the problems caused as, as you can see, when things go south it generally results in complete and utter disaster.

[RPK]

Agree. Gt2 torgue band is wide enough as is . Thanks again Silver.

[RPK]

Yes...thanks again !

[Silver_TT]

np.... and btw, just by way of clarification, that link pertains to the M96 engine specifically, you have a Mezger as you stated you have a GT2 -- but irrespective of that, I still like the dual mass unless you use your car as a pure track car..........which it looks like you have already concluded anyway.  :cheers:

[RPK]

i believe 996 , 997 GT cars have the Mezger engine which is said to have a stronger crank compared to M96 but I am sticking with the stock Dual Mass Flywheel anyways .... now waiting for the SACH Stage 2 clutch which is taking forever. 

 

On another note saw the 991 GT3 RS earlier in the week - noticeably bigger wheel /bigger arches , front and back = stunning! Would one trade a manual 997 Gt2 for a PDK GT3 RS ? 

[JFP in PA]

Let's see, one had an MSRP of $85K, the other $175K.  What do you think?