S4 Uprated Clutch

[rweir]

Hi Guys,

My car has been upgraded quite a lot and has (not sure just how much yet)got 400+ BHP. The standard clutch is not bearing up very well with first gear starts (more the 0-60 ones!) so I think I am going to have to replace it in the near future ...

Who can recommend a clutch? MTM? I would like a really good one, but I have heard reports that if I go the full way and get a competition type clutch after it is warm there is not clutch control, it is basically on/off idea, I guess I am looking for something as strong as this, but with a little give since I do use the car on the road as well...

Thanks in advance...

Rich [img]images/graemlins/s4anogaro.gif[/img]

[PhilT]

Carl may have something for you (Up to 650nm and 600hp). Otherwise, if you can wait, I think there will be a clutch available that will handle 600+ bhp.

[rweir]

I think 600+ BHP would be enough for me [img]images/graemlins/thumbs.gif[/img]

I'll wait to see if Carl can help me with this, the clutch is still ok for a while yet I think.

When I am doing my 0-60 times I am putting full rev's and dropping the clutch ... I take it this is putting some major stresses on different parts of the car .. So I am not doing this often! but if the tyres are a little hot they stick too well and the clutch just slips ...

I take it this is the way to get the best times if doing drag strip stuff out of the car? I just always hate doing it because I feel something is gonna break!! [img]images/graemlins/033102bad_1_prv.gif[/img]

r

[Joshie]

When I am doing my 0-60 times I am putting full rev's and dropping the clutch ...

I take it this is the way to get the best times if doing drag strip stuff out of the car? I just always hate doing it because I feel something is gonna break!! [img]images/graemlins/033102bad_1_prv.gif[/img]

r

Something WILL break mate - believe me.

I ran my car at Elvington a year past November. I was running about 400Bhp through a brand new RS4 clutch. The input shaft on 1st gear twisted and then subsequently first gear whined like hell.

So the initial euphoria of achieving a 12.3 s atanding quarter was quickly replaced with dispair as I had to fork ot big time for a gearbox rebuild. And that's where big problems started................... [img]images/graemlins/suicide.gif[/img]

[rweir]

So the initial euphoria of achieving a 12.3 s atanding quarter was quickly replaced with dispair as I had to fork ot big time for a gearbox rebuild. And that's where big problems started................... [img]images/graemlins/suicide.gif[/img]

Ahh, I hear you! I should give up on that front now before it takes something to break to stop me [img]images/graemlins/062802beat_prv.gif[/img]

r

PS. 12.3!! Very nice! Do you know you 0-60 time in that?
I was at Elivington in the summer last year, first and last track day, ended up going through a set of new front stock disks and pagit pads!! and that was before the upgrade!

[DavidT]

Yep, I agree with Ian.

They are not designed to take that level of abuse, few if any road cars are.

The clutch is currently the weakest point in the drivetrain and is protecting the more expensive components further on. If you strengthen that, the torque will break something else - gearbox, driveshafts, whatever.

I would also say that an RS4 clutch is the ideal upgrade as it will be fine with 450 bhp, the stronger you go the more the above scenario becomes true.

Just my 2p

[runrowsam]

It's certainly a good way of thinking about it, that the clutch is the only thing saving the rest of your highly expensive transmission. Upgrading it's not a bad idea so long as you respect the limits of the rest of the transmission. Just dropping the clutch at full revs is a bad idea in any case though. Unless you have a narly transmission, clutch and suspension setup there's no point, and if you had all that then you'd just have a beautiful four wheel burnout going on, and that takes some REAL power.

Your best bet for a quick getaway is probably about 4,000rpm, and let the clutch out slightly less abruptly. It's still not great for your transmission, but it's certainly better than the bitching you've been giving it! Ideally you want to get the clutch all the way out asap ie full transmission connection so you can get the power down straight through the transmission, rather than straight through your clutch.

Hope this makes some sense for you.

Rock on
Sam [img]images/graemlins/thumbs.gif[/img]

[rweir]

Thanks for the input guys,

When I do the full rev thing and dump the clutch I normally get a 4wheel spin and then its time for 2nd gear. The problem with letting the clutch out slowly with the current clutch is that it will not bite, I need to do a rolling start really to get it to bite...

It is annoying that Audi say the S4 can do a 0-60 in 5.5s, but the only way I can see to achieve this is the dump the clutch at full revs!

Anyway, this is something that I do not intend to do all the time for the reasons stated above, just trying to see what my car is capable of, lets just hope I don't break it finding out!

Hmm, would be nice to have endless amounts of cash to spend would it not? [img]images/graemlins/jesterlol.gif[/img]

r

[Joshie]

12.3!! Very nice! Do you know you 0-60 time in that?

Actually it was 12.4s - the slip is in my gallery. Terminal speed 107 MPH but no other split times.

[Joshie]

When I do the full rev thing and dump the clutch I normally get a 4wheel spin and then its time for 2nd gear.

Thats what I experienced.

The problem with letting the clutch out slowly with the current clutch is that it will not bite, I need to do a rolling start really to get it to bite...

True. If you try and feed the clutch in it slips. So what you have to do is either dump it (brutal) of slip it with very few revs on board. The latter option means a very poor time, I'm afraid.

Trouble is that the explosive acceleration is so addictive it is a pity not to pratice it more often - the only issue though is the impact it wil unboubtedly have on your wallet.

Hmm, would be nice to have endless amounts of cash to spend would it not? [img]images/graemlins/jesterlol.gif[/img]

Too right - but thats always the way when you're running an S4 IMO.

[rweir]

I have the feeling that hopefully I will get a good time and I will be happy with that and stop [img]images/graemlins/shocked.gif[/img]

But you are right the explosive start is quite something, my little gadget read 0-27 mph in 1.25s which is pretty quick by any cars standards!! [img]images/graemlins/biggrin3.gif[/img]

Mind you, need to think about this since it is my only car, getting to work would all of a sudden become a rather large issue! then again, if I am going to change the clutch I feel I may as well go for something that is going to last, lets just hope, as David was saying that the rest of the car does not suffer!! but I guess thats down to my 'spirited driving' style [img]images/graemlins/033102bigblink_1_prv.gif[/img]

r [img]images/graemlins/s4anogaro.gif[/img]

[DavidT]

The other thing you may want to consider if/when you replace the clutch is a lightweight flywheel as it will improve the torque figures - less mass for the engine to accelerate, therefore more torque.

Tanoga on here manufactures and sells them.

[runrowsam]

I'm not very clued up on the actual clutches available, but I'd have thought from a physics perspective, that you want to be able to progressively build up the load on the clutch and transmission. It's a fairly grounding principle that if you apply a force graduall and build it up, the force you can apply before everything goes bang is a lot higher than if you just slammed that force on. It's why driving smoothly and progressively gives you a better lap time and doesn't destroy your tyres etc as much as ragging it.

In theory perfect takeoff would be to hold the revs at your peak torque point and let the clutch out as rapidly as you can while holding those revs. That's why some automatic transmissions can really get away well once they're actually moving. In a manual you get that better starting connection, but after that an automatic will be able to progressively build up the power (as the revs will start from idle and build up), rather than be howling away at 6,000+rpm with a load of smoke.

Rock on
Sam [img]images/graemlins/thumbs.gif[/img]

[bem_ho]

Other then MTM, you can take a look at this!

http://www.unorthodoxracing.com/index.html

[Joshie]

In theory perfect takeoff would be to hold the revs at your peak torque point and let the clutch out as rapidly as you can while holding those revs.
Rock on
Sam [img]images/graemlins/thumbs.gif[/img]

Certainly the fastest way off the line as long as you understand the quite high risks to the drivetrain involved in this procedure.
[img]images/graemlins/062802beat_prv.gif[/img]