Need a new clutch..
Discussion
Hi All,
Does anyone know if the +35% clutch that Marcus (PUK) sells is stronger than an S4s clutch?
I'm replacing the stock clutch on my S4 this winter and I'm trying to decide which way to go as far as a replacement.
If the S4s clutch is stronger I will spend the extra cash and replace the flywheel to make it work on my S4.
Thank's,
Mike
>>> Edited by mikelr on Tuesday 16th November 09:16
Does anyone know if the +35% clutch that Marcus (PUK) sells is stronger than an S4s clutch?
I'm replacing the stock clutch on my S4 this winter and I'm trying to decide which way to go as far as a replacement.
If the S4s clutch is stronger I will spend the extra cash and replace the flywheel to make it work on my S4.
Thank's,
Mike
>>> Edited by mikelr on Tuesday 16th November 09:16
Hi Mike,
The stock S4s-clutch will not fit on your S4 flywheel. Additionally the stock S4s-clutch is weaker and does not last long and it has a horrible too hard pedal feel.
I personally donot like the stock S4s-clutch. IMHO its way too hard to press and not really high performance and also not very reliable.
Cheers
Marcus (www.PUKesprit.de)
The stock S4s-clutch will not fit on your S4 flywheel. Additionally the stock S4s-clutch is weaker and does not last long and it has a horrible too hard pedal feel.
I personally donot like the stock S4s-clutch. IMHO its way too hard to press and not really high performance and also not very reliable.
Cheers
Marcus (www.PUKesprit.de)
Hi Marcus
As I own an S4s, is there anything that can replace the stock clutch that is better / stronger?
(Just for future reference)
Also, personally I don't find the clutch too heavy, only in traffic, but then again I don't sit with my foot holding the pedal down constantly so it's not really a problem.
Jez
As I own an S4s, is there anything that can replace the stock clutch that is better / stronger?
(Just for future reference)
Also, personally I don't find the clutch too heavy, only in traffic, but then again I don't sit with my foot holding the pedal down constantly so it's not really a problem.
Jez
Hi Jez, Hi Madmax,
The problem with the S4s clutch is the pressure-plate-spring design. It just transfers too much load on the release-fork and the slave cylinder.
Best method is to take the PUK +35% clutch and drill the new fixing-holes into the existing flywheel. This is not a big task. Every simple machine shop can do that for you within half an hour. Of course you may also replace your existing flywheel with an S4-flywheel if you have one at hands ;o)
I will never understand why Lotus choosed a clutch like this for the otherwise marvellous S4s ...
Cheers
Marcus (www.PUKesprit.de)
The problem with the S4s clutch is the pressure-plate-spring design. It just transfers too much load on the release-fork and the slave cylinder.
Best method is to take the PUK +35% clutch and drill the new fixing-holes into the existing flywheel. This is not a big task. Every simple machine shop can do that for you within half an hour. Of course you may also replace your existing flywheel with an S4-flywheel if you have one at hands ;o)
I will never understand why Lotus choosed a clutch like this for the otherwise marvellous S4s ...
Cheers
Marcus (www.PUKesprit.de)
JAE sells a newer, lightened flywheel as well so if you go the PUK route, hit up JAE for the flywheel. This is what I did when I thought my clutch went south. Turned out to be out of adjustment by a lot so now I have the lightened flywheel and +35% clutch from Marcus waiting for it's moment.
Also, if you get the PUK, you may be able to machine your flywheel. Could save you a lot of money. If it is going to be down for the winter anyway, pull it, see if the flywheel is machinable and take it from there.
Also, if you get the PUK, you may be able to machine your flywheel. Could save you a lot of money. If it is going to be down for the winter anyway, pull it, see if the flywheel is machinable and take it from there.
Marcus said:
The problem with the S4s clutch is the pressure-plate-spring design. It just transfers too much load on the release-fork and the slave cylinder.
Marcus,
Could you elaborate more on the design and how your 35% clutch resolves the problem?
Thanks,
Rich Flowers
'95 S4s ...SHF63000
'79 JPS #040
Hi Rich,
Its not too easy for me to explain ... (when you look at an original S4s-cluch in comparison to a S4-clutch you will see it instantly) ... but I will try to explain: It has to do with the "lever-arm" of the diaphragma spring. The spring is fairly stiff (of course, it has to be stiff) and the release-lever arm is relatively short. This makes it heavy to press ... on the other side the lever-arm that is responsible for pressing the plate is fairly long and therefore reduces the clamp force .... hmmmmmmmm ;o(
The uprated PUK-clutches are NOT like the S4s-clutch they actually share the same well proven design like the SE/S4-clutch. Of course with uprated components
)
Cheers
Marcus
Its not too easy for me to explain ... (when you look at an original S4s-cluch in comparison to a S4-clutch you will see it instantly) ... but I will try to explain: It has to do with the "lever-arm" of the diaphragma spring. The spring is fairly stiff (of course, it has to be stiff) and the release-lever arm is relatively short. This makes it heavy to press ... on the other side the lever-arm that is responsible for pressing the plate is fairly long and therefore reduces the clamp force .... hmmmmmmmm ;o(
The uprated PUK-clutches are NOT like the S4s-clutch they actually share the same well proven design like the SE/S4-clutch. Of course with uprated components
) Cheers
Marcus
Marcus,
Would I be correct in saying that you changed the fulcrum point for the pressure plate spring? See orange pins in http://auto.howstuffworks.com/clutch3.htm
Thanks,
Rich Flowers
'95 S4s ...SHF63000
'79 JPS #040
Would I be correct in saying that you changed the fulcrum point for the pressure plate spring? See orange pins in http://auto.howstuffworks.com/clutch3.htm
Thanks,
Rich Flowers
'95 S4s ...SHF63000
'79 JPS #040
Hi Rich,
The Esprit clutch is a bit different. It does not have the orange pins. The diaphragma spring is not flat its rounded and behaves like a "frog-spring" (this is a German word ... actually borrowed from an old fashioned toy ;o)
Besides that you are absolutely rught !)))
Cheers
Marcus
The Esprit clutch is a bit different. It does not have the orange pins. The diaphragma spring is not flat its rounded and behaves like a "frog-spring" (this is a German word ... actually borrowed from an old fashioned toy ;o)
Besides that you are absolutely rught !
))) Cheers
Marcus
Marcus,
How did you come to the determination that your upgraded clutch set has 35% more clamping force than stock?
Do you have technical data to back this up? Have you possibly though the use of digital strain gadge positioned between the pressure plate and the clutch disc (of each clutch style) made this observation?
Sorry for all the questions.
Thank's
Mike
How did you come to the determination that your upgraded clutch set has 35% more clamping force than stock?
Do you have technical data to back this up? Have you possibly though the use of digital strain gadge positioned between the pressure plate and the clutch disc (of each clutch style) made this observation?
Sorry for all the questions.
Thank's
Mike
Hi Mike,
The torque abilities were found out very practical. You just have to bolt the whole clutch unit on a flywheel and insert a spline with attached torque-wrench (extended with a fairly long lever) to the friction disc. You can easily read directly from the torque wrench what max. torque the clutch can handle (when cold)
Please keep in mind that its the torque, not the clamping force.
Torque -> clamping force * friction coefficient
Cheers
Marcus
The torque abilities were found out very practical. You just have to bolt the whole clutch unit on a flywheel and insert a spline with attached torque-wrench (extended with a fairly long lever) to the friction disc. You can easily read directly from the torque wrench what max. torque the clutch can handle (when cold)
Please keep in mind that its the torque, not the clamping force.
Torque -> clamping force * friction coefficient
Cheers
Marcus
Very good Marcus!
Now if the US dollar would just build up a little steam against the Euro, I'd buy one.
$750 + international shipping for a clutch and pressure plate is a bit steep when I can buy the stock parts here in the US for $340.
Having any sales for Christmas Marcus? ;-)
PS, That must have been a BIG torque wrench, you must have been up in the 300-400 ft/lb range to get the disk to slip no?
>> Edited by mikelr on Wednesday 17th November 09:11
Now if the US dollar would just build up a little steam against the Euro, I'd buy one.
$750 + international shipping for a clutch and pressure plate is a bit steep when I can buy the stock parts here in the US for $340.
Having any sales for Christmas Marcus? ;-)
PS, That must have been a BIG torque wrench, you must have been up in the 300-400 ft/lb range to get the disk to slip no?
Paula&Marcus said:
Hi Mike,
The torque abilities were found out very practical. You just have to bolt the whole clutch unit on a flywheel and insert a spline with attached torque-wrench (extended with a fairly long lever) to the friction disc. You can easily read directly from the torque wrench what max. torque the clutch can handle (when cold)
Please keep in mind that its the torque, not the clamping force.
Torque -> clamping force * friction coefficient
Cheers
Marcus
>> Edited by mikelr on Wednesday 17th November 09:11
Mike,
Yes, actually I ruined the first wrench .... ;o/
You will have to play with figures more than 500 Nm.
Additionally there is a lot of difference between break-loose-torque and slipping-torque !!!
Sticking-friction-coefficient (w=0) is nearly doubled vs. slipping-friction-coefficient (w>0)
Mike, maybe I´m a bit biased, but before you take the stock one I´d take the +25% clutch. This one is absolutely the same design like the +35% clutch ... and way less expensive
Cheers
Marcus
Yes, actually I ruined the first wrench .... ;o/
You will have to play with figures more than 500 Nm.
Additionally there is a lot of difference between break-loose-torque and slipping-torque !!!
Sticking-friction-coefficient (w=0) is nearly doubled vs. slipping-friction-coefficient (w>0)
Mike, maybe I´m a bit biased, but before you take the stock one I´d take the +25% clutch. This one is absolutely the same design like the +35% clutch ... and way less expensive
Cheers
Marcus
marcus, could you tell me the claumping force, other than by a percentage? For instance, the stock clutch pressure plate of a Talon is somewhere around 1800lbs. The common upgrade is made by ACT and is a 2600lb PP. They also have a stronger one for all out drag cars which si a 2900lb pressure plate.
What, if you know or can find out, is a stock S4? Stock S4s? Your +25% or +35%.
More a curiousity. thanks.
What, if you know or can find out, is a stock S4? Stock S4s? Your +25% or +35%.
More a curiousity. thanks.
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