Clutch Slip

[Rob GTI]

Any one had clutch slip in a TFSI yet, I noticed it a few times over the last couple of weeks. Strangely enough only since I fitted a milltek downpipe. It only ever last a couple of seconds when the car is at about 3k revs it shoots up to nearly 4k revs for a few seconds and then returns to normal???

 

[cupranicko]

I have the same problem in my cupra 355hp/480nm...

new clutch I think??

 

[HotHatchSteve]

Could it be the Dual Mass Flywheel slipping ?

 

[Nath.]

How on earth does a flywheel slip?

 

[HotHatchSteve]

When Dual Mass Flywheel are fitted, from my understanding the DMF has 2 sections seperated by a friction material and when a preset torque is exceeded the 2 sections slip.

This web page gives a good explanation.
http://www.northernautoparts.com/ProductDetail.cfm?ProductId=2673

 

[Nath.]

When Dual Mass Flywheel are fitted, from my understanding the DMF has 2 sections seperated by a friction material and when a preset torque is exceeded the 2 sections slip.

This web page gives a good explanation.
http://www.northernautoparts.com/ProductDetail.cfm?ProductId=2673

That's not how I understand it at all. the ones I have seen are seperated by rubber blocks and springs. The second mass works as a damper to smooth out vibration in the drive train. There is some "slip" or movement but only a few degreess so as to sort of shake the second mass of the flywheel rather than shake the gearbox and engine.

This may help you understand although it's not exactly the way the ones I have seen worked but you should get the idea.

 

[HotHatchSteve]

I thought that under normal use the two surfaces of DMF twist slightly but when the defined torque is exceeded the friction ring engages allowing the two srfaces to slip and preventing damage.

 

[Nath.]

Nope methinks you have some duff info there mate.

 

[HotHatchSteve]

Have look at this post on the AudiWorld forum.
http://forums.audiworld.com/showthread.php?t=2166434
It might be my interpratation. This information is repeated on differant sites.

 

[Nath.]

Ok, That's some weird flywheel. If you had a fooked one of them it may slip rather than self destruct. This seems to be the reason for the design.

If it was to slip it wouldn't show up as clutch slip. What you have is a normal clutch with a DMF that has a self destruct protection system that makes it slip into SMF mode. This doesn't make the transmission slip as the clutch is still fully engaged and works as normal.

If one of these things slips like this you would just get extra vibration as you effectively have only a SMF whilst it's slipping. As you can see from the diagram you still have the clutch disk mated to the primary part of the flywheel to engage drive.

So it seems that you are correct that in some situations of failure some designs of DMF can slip but this slip does not manifest as "revs rising without speed rising" like clutch slip does.

 

[HotHatchSteve]

So it seems that you are correct that in some situations of failure some designs of DMF can slip but this slip does not manifest as "revs rising without speed rising" like clutch slip does.

I did think this my self untill about 12 mths ago. I was having a bit of fun in my current car (Astra 200+) and trying to see what I could do 0-60 in, gave it to much revs at the same time I lifted the clutch and it excellerated but not quickly but the revs climbed quickly. When I changed gear though all went OK. Had the stealers have a look thinking the clutch slip was the problem (car under waranty). Clutch checked OK and that was when I first dicovered about the DMF. Car has been fine since.