The Clutch Conundrum

It seems my clutch is starting to slip (in 6th at WOT) a little. I have some mods, but I’m running the stock tune and I drive easy most of the time, only occasionally going WOT. So at 39,900 miles this was extremely surprising. I’m been driving manuals for nearly 50 years, and usually get well over 100,000 miles from the OE clutch, and it’s the friction material that wears out. I learned at the beginning of my driving career to not rest a foot on the clutch and wear out the throughout bearing.

So I’ve been researching this and here’s what I’ve found out:
The clutch system in our R’s is a weak point. I’m guessing the VAG did their engineering work on the engine upgrades and AWD system and went to the parts bin for the transmission and clutch using the golf Dual Mass Flywheel (DMF) system that’s used for all manual golfs.

From what I’ve been able to figure out, the DMF allows the 2 flywheels to spin somewhat independently until the springs engage. The springs are centrifugally activated.

This system is good, actually great, for most Golfs, but modded GTI’s, R and TDI that put out torque in the 250+ range seem to be able to easily cause slippage between the flywheels. Judging from the number of clutch replacements noted on this forum and the VW Vortax the friction material often looks like new. The probable cause of this problem is that the springs engaging the centrifugal clutches are too weak, and they probably weaken with age. Tuned R’s and TDI’s quickly wear the OE DMF design.

Two solutions:
An oversized DMF set up, the HS RSR is an oversized set up and a lot of people seem to have good luck with this…
http://www.hstuning.com/product_info.php?cPath=15_18&products_id=3888
or
Convert to a Single Mass Flywheel (SMF), which may have a little chatter when engaged in neutral but will not be susceptible to the failure of the DMF and will probably last 100,000 miles. The SMF is a must if you plan on tracking your car.
Example: https://www.sachsperformance.com/en...lutch-sachs/clutch-with-flywheel-883089000034 the SMF on this is less than 16 lbs.

Sticking with the OE DMF (reconditioned or new)seems to be an unacceptable solution unless you like doing clutch jobs….

It's not that the springs inside the flywheel 'engage' - they're always engaged and dampening NVH. It's doing the same job as the sprung hub on old clutches, just with a higher capacity.

They had two different clutch suppliers - Sachs and Luk. From what I've been able to tell, it's the Luk flywheels that had the trouble. Mine finally let go at 95k; when I took it out, the original DMF (mine was a Sachs) was still tight and quiet. It was the disc and pressure plate that weren't up to the task.

I replaced it all with a Clutch Masters FX250 and their 20lb SMF. The clutch itself is great, but on the street the lightweight flywheel is all negatives and no positives - I get a LOT of chatter (not just at idle) and engine braking isn't as effective. Acceleration is a bit better than before, but I don't know how much of that is from the replacement clutch holding harder.

If I had it to do over again, I'd get the same clutch kit, but with a rigid disc and a new DMF.

Well, first you shouldn't be doing WOT pulls in 6th gear. 4th or 5th are much faster and you won't be putting that strain on your clutch. 6th gear is really a cruising gear.

Yeah, I was in 6th and a semi was coming down my back fast and I reacted. He was probably at 80 and I was at 65. Probably wouldn't have happened in 5th.

TimS said:

It's not that the springs inside the flywheel 'engage' - they're always engaged and dampening NVH. It's doing the same job as the sprung hub on old clutches, just with a higher capacity.

They had two different clutch suppliers - Sachs and Luk. From what I've been able to tell, it's the Luk flywheels that had the trouble. Mine finally let go at 95k; when I took it out, the original DMF (mine was a Sachs) was still tight and quiet. It was the disc and pressure plate that weren't up to the task.

I replaced it all with a Clutch Masters FX250 and their 20lb SMF. The clutch itself is great, but on the street the lightweight flywheel is all negatives and no positives - I get a LOT of chatter (not just at idle) and engine braking isn't as effective. Acceleration is a bit better than before, but I don't know how much of that is from the replacement clutch holding harder.

If I had it to do over again, I'd get the same clutch kit, but with a rigid disc and a new DMF.

Click to expand...

does you friction plate have organic material on one side and ceramic on the other?

My understanding is that the high performance materials like ceramic and copper aren't as street able.

is the chatter coming from the springs on the disk? is that why the rigid disk?

I've also been wondering about the light weight flywheel.

Sachs has a performance DMF with a rigid disk...

thanks for you input.

bebersol said:

does you friction plate have organic material on one side and ceramic on the other?

My understanding is that the high performance materials like ceramic and copper aren't as street able.

Click to expand...

Yeah, organic on the flywheel side, ceramic pucks on the pressure plate side. It actually feels pretty close to stock, just a little firmer and engagement is nice and crisp.

is the chatter coming from the springs on the disk? is that why the rigid disk?

Click to expand...

No, it's from removing the dual mass flywheel. That thing soaks up a LOT of noise and vibration. The rigid disc kit is for use with the OEM flywheel, so you get better engagement and keep the benefits of the DMF.

The current setup isn't hard to drive by any means, it just rattles a bit more than I'd like.

Thanks,

I think I'm figuring it out. there's no harmonic balancer on our engine, the DMF is used for this purpose. I guess this is why so many have had good success with the HS RSR setup. As lightly as I've driven my R I'm nut sure why the DMF is giving up, it may be a LUK, but their manufacturing looks pretty German too.

https://www.youtube.com/watch?v=DbvP5EvpUbA

or
https://www.youtube.com/watch?v=gZpTQW21_yc&t=20s

and
https://www.youtube.com/watch?v=gG-NliCZ2U8

Have you looked at the Southbend Stage 3 Daily? I don't have it, but it is one of the finalists for me.

FWIW, I have been using OEM DMF with RSR at stage 2+ for over 60k miles and it's been fine. I drive spirited regularly but haven't tracked it or launched it ever.

If you're not doing clutch drop launches your OEM DMF is fine. They are pretty stout. I've been running my RSR for ~50k miles. 40k of which was K04 and 10k of which was BT. Zero issues.

I love the RSR myself as well. Although I only have 10k at this time I am confident I will get many many more miles. I had the exact same issue as you with 6th gear slippage. In my case it happened stage 1 and now I am stage 2 with the RSR. I currently have 60k on the car.

Yeah, it seems that the OE pressure plate may be the culprit for the slippage. so new friction material and a higher rated pressure plate seems like is should solve the problem.

thank you everyone