Boxster S Clutch - what stage?
 

I'm replacing the IMS bearing and while I'm at it at 65,000 miles I thought I'd replace clutch as well. The car will be an every day driver, but we enjoy driving it like a sports car, but no racing. So I ask, what experiences do you have with clutches and which to invest in from longevity and durability? If there already is a thread discussing this I did not find, still a newbie. (2002 Boxster S) Thanks!

The stock Sach clutch is all you want. The only upgrade is to have it & a new dual mass flywheel balanced.

Or the smart upgrade; the aasco lw flywheel and Sachs clutch.

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Yeah these engines are so robust why would it need any Harmonic dampening?? :rolleyes:

OK, how do you balance them; is a this a common request at an indy shop? Im wrenching everything myself, but could hoist the parts up to the Lambo shop in my area. I have the clutch, pressure plate and flywheel...all of them?

Let's make sure we're talking about the same thing here, before we disagree about it.

The correct word for reducing the amplitude in waves (sound, or harmonic) is "damping" or "to damp."
The word "dampen" or "dampening" means to make damp or moist, and is concerned with liquid, not sound or harmonics.

So: if you're rolling your eyes because you think these motors aren't already wet enough, and they need a dual-mass clutch to make them wetter..... well.... :confused:

BUT: if you meant to say that the motor needs the dual mass flywheel for it's damping effects.... I'd argue that on its merit... all day and twice on Sunday.

A dual-mass flywheel is an incredibly ineffective way to provide harmonic damping for a motor. It does NOT act the same as a harmonic balancer (very common). IF this motor required harmonic damping, don't you think Porsche would've designed some way of providing such? (And they PROBABLY would've used one of the existing, engineered, effective measures?)

Yup, it is so ineffective that several manufacture's have been using it for years......

I didn't say it's ineffective... I said it's a relatively ineffective way to provide harmonic damping / balancing. Which is true. Unless you always have the clutch disengaged.

It is effective at several other things, which, I believe, are the reasons Porsche (and several other manufacturers) have been and continue to use them. I do not believe that the harmonic damping is the driving cause for the use of a dual-mass flywheel for any of the manufacturers or road-going automobiles.

You'll want the pressure plate and flywheel, and the bolts that attach. They'll balance it as an assembly, and then index it for you. Be sure to install it properly indexed.

And, when they tell you "I can't balance a dual-mass flywheel", you can come back to this thread and explain that to the nay-sayers.

Well, according to Sachs and LUK, two of the largest manufacturers of them, that is exactly why they are used. Google it...…….……

The primary reason Porsche when with it in the 986 is that the M96 engine is also used in the 996, which has a crossmember directly in the way of the front of the engine, requiring as thin a front pulley as possible, thereby precluding a thicker coventional harmonic dampener:

https://cdn4.pelicanparts.com/techar...arge/pic04.jpg

Well, if GOOGLE says it....... hehe. Jus' teasin', JFP.

I'm not sure what reference you're finding, BUT, I would bet that it likely says something about "damping" or "absorbing" vibrations in the drivetrain, or driveline, and not specifically the engine. That is the primary purpose of the Dual Mass FW.

I've done a TON of information-gathering on this topic. I've read dozens of papers about the development of Dual Mass fw's; the why's and the wherefore's. I've spoken with manufacturers of both dual mass and single mass, (including one who manufactures both). AND: I've scoured the internet for statistics. You don't have to take my word for anything, but my hope is that people quit presenting as gospel-fact something that just simply doesn't stand-up to scrutiny.

What I have found is that, in ALL OF THE INTERNET, there is ONE, SINGLE, SOLITARY confirmed and DOCUMENTED instance of an M96 crank failure that has been attributed to a LWFW. And even in that instance, the motor in question had countless other modifications. On the other hand: speaking to just ONE manufacturer of a Single-Mass flywheel for the M96/M97 motor, they have sold thousands of them, with not a single claim against them for it being responsible for a motor failure. Not One. and that's only ONE of the mfr's of these LWFW's.

It is very, very easy to find literally HUNDREDS of users of LWFW's in these cars, in America, who have many thousands of miles on them, including many hundreds-of-thousands of racetrack laps, with no ill-effects whatsoever. And when you lay that up against a single documented failure (which remains questionable to me), the fear-mongering just doesn't hold water.

As to the "why they chose to use the least effective method of vibration-damping": your suggestion is that it's because there wasn't room on the front of the motor. Well, my suggestion would be that it's because A) the possibility for harmonic vibration wasn't so great that they felt it warranted a very-mild-redesign of a cross-member, and B) putting it on the front of the motor would have ZERO effect at reducing vibration / harmonics from the drivetrain, which was the primary interest.

Oh, and, would you mind resizing your photos before putting them on here? It's KILLING me, hahahaha. :)

Funny, I never said ANYTHING about your cherished light weight flywheel…….

"A dual-mass flywheel (DMF) is a rotating mechanical device that is used to provide continuous energy (rotational energy) in systems where the energy source is not continuous, the same way as a conventional flywheel acts, but damping any violent variation of torque or revolutions that could cause an unwanted vibration. The vibration reduction is achieved by accumulating stored energy in the two flywheel half masses over a period of time but damped by a series of strong springs, doing that at a rate that is compatible with the energy source, and then releasing that energy at a much higher rate over a relatively short time"

From a LUK white paper on DMF theory:

"The primary feature of the DMFW is the almost complete isolation of torsional vibrations."

"The DMFW permanently alters the vibration system of the crankshaft. In
the conventional system, the heavy flywheel including the clutch is rigidly
connected with the crankshaft. The large inertia of the flywheel generates
high reaction forces on the crankshaft.
The DMFW system behaves more favorably because the secondary
flywheel mass can be disregarded for the bending load. It is only very
loosely connected via the torsion damper as well as via the roller bearing to
the primary flywheel mass and therefore generates practically no reactions.
The primary flywheel mass is much lighter than a conventional flywheel and
is also elastic, like a flexplate for a torque converter.
Inherent bending and torsion resonance forms change with the DMFW in
comparison to a conventional system. The crankshaft is mostly relieved.
Figure 7 illustrates a measured example. Both torsion and bending
vibrations are lower with the DMFW. In individual instances, it must be
decided whether the crankshaft damper can be omitted or if a simpler
material can be used for the crankshaft, such as a casting."

Sure sounds like the people that make them believe other wise about what a DMF does...……..…...

Sounds to me like we're talking about a different type of dual mass flywheel. What LUK is describing there is a far cry from what's installed on the M96. Those types of dual-mass flywheels have been used on large-equipment motors for quite some time, and are in production cars recently because of the significant vibrations inherent in small 3, $ 4 cylinder motors with very small displacement, where the firing pattern doesn't allow for an even delivery of power. But even then, the number one concern is the transfer of that uneven torque / vibration / sound / harmonics to the driveline.

And as to your snarky comment about my "cherished" lwfw: that's how we GOT to this conversation, friend. And that's the only reason I can think of to ditch the comfort of a dual-mass flywheel. (can YOU think of another reason?)

there was really no need to get personal about this, JFP. we were being friendly. maybe a little sarcastic, hehe but friendly.

I think some of y'all have become very comfortable tossing-out "conventional wisdom", as if it were fact. I realize that's very common: the more something gets repeated without being challenged, the more it is just accepted as truth. The problem is that now you're offended when someone challenges it. I'm not being rude, I'm questioning because it's what I do: I'm a "disruptive innovator" by trade. If it doesn't make sense, then let's change how we're doing it. If conventional wisdom is right, then let's keep it. But if it doesn't hold-up to scrutiny, then let's put it back in the "needs further research" category. (or even the "myth debunked" category)

here you go; everyone can be friends now ...

608 - Harmonically Damped - Underdrive Performance Pulley Kit (986, 987, 996, 997) - RSS / Road Sport Supply

i'd buy one, but can't get it in 4".

I don't believe the O.P. was looking to spend more money than necessary, or make the clutch more difficult to operate.

[QUOTE=tonythetiger;597112]OK, how do you balance them; is a this a common request at an indy shop? Im wrenching everything myself, but could hoist the parts up to the Lambo shop in my area. I have the clutch, pressure plate and flywheel...all of them?[/QUOTE

It takes specialized equipment to properly balance & it's better & easier with a crankshaft.


I use Revco in Long Beach CA

Don't be :confused: that's not why I am rolling my eyes Drama Queen!

Oooohhhhh..... I LIKE IT! hahaha

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DMF's come in many physical and mechanical configurations, the use of elastomeric separators like those found in the 986/987 DMF are just the latest and lowest cost variety, which is very common in modern passenger cars.

The white paper I referred to is just one of several available that trace the development and evolution of the concept from its first automotive use in 1985; it is hardly "conventional wisdom", but more an attempt to document the history, practical use, and end value of an idea from the first bent spring design to the current use of elastomeric materials.

To put an end to this as I can clearly see not interested in the background of why the DMF was developed and deployed, as well as what it was designed to do, just remember that there is "needs further research", and then there is what is called conformational bias, which implies disregarding whatever data does not fit a preconceived notion...….

Have a nice weekend.

10-4. Can't always read between the lines correctly in a format like this, Haha.

Cheers!

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