Clutch material info and input...

[silvercoffin]

To be safe I think I will still put a good 300 or more miles on my sec 2 before racing, but I am conflicting info regarding clutch material.

I was told by a mechanic that organic clutches need very little break in and I have read that, but he says the same goes for my stage 2 spec which is 100% kevlar. He says that the kevlar needs very little break in and less break in than a sintered iron clutch. I have read that and have also read just the opposite!

I have read that:

stage 1 clutches or stock replacements are usual organic and require little or no break in. Although companies still say 500 miles just to be safe. Some companies claim the same goes for kevlar but.....

The next step up are often kevlar or a kevlar mix and some sources say they require a careful break in because of the material. Kevlar is weird because info I have found says it has a better friction coefficient but that if it gets burned up it does return to normal like an organic clutch will if you burn it a little too much. Still Kevlar is recommended for high temps and higher tq applications over organic.

I also read that Kevlar is not good for stop and go driving and that it will glaze and then once driven hard go back to normal. If that is true then why does it need to be broken in? Is it even good to break it in because city driving is not good for it.

The next step up is usually a combo of metallic materials. Little is ever said about the break in needed for these materials

The top of the clutch disk material is SIntered iron. I was under the impression that it needs less break in.. Again the companies always recommend 450-500 miles anyway.. But my spec 3+ which I believe is a mix of sintered iron and some other metallic definetely changed during the break in period.

Does anyone really know about the different materials?

In my case, I am looking for a clutch that will hold the power but that I can slip off the line...or feather the pedal. Thats the way I have achieved my best launches. With my Spec 3+ sintered iron you cant drive that way.

 

[silvercoffin]

more info....

Just found this...definetely goes against what my mechanic friend told me about the break in. Still dont get how a break in is needed for kevlar if it isnt recommended for city driving! Someone explain that to me.



organic
CHARACTERISTICS Metal-fiber woven into "organic" (actually CF aramid with other materials), original-equipment style. Known for smooth engagement, long life, broad operating temperature, minimal-to-no break in period. Will take hard use, somewhat intolerant of repeated abuse (will overheat). Will return to almost full operational condition if overheated. Material is dark brown or black with visible metal fibers.
USE Street-driven cars up to 400hp, auto-x and track use.

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kevlar
CHARACTERISTICS A high-durability material more resistant to hard use. Engagement is similar to organic, but may glaze slightly in stop-and-go traffic, resulting in slippage until worn clean when used hard again. Higher temp range in general, but can be ruined from overheating - will not return to original characteristics if "cooked". Has a break-in period of 500-1000 miles during which slippage may occur. Care must be taken during this period not to overheat from excessive slipping. Material is uniform yellow/green and may look slightly fuzzy when new.
USE Street-driven track cars up to 500hp, auto-x and heavy track use. Will take hard use, intolerant of abuse (will overheat and not recover completely). Due to the unforgiving nature of Kevlar, it is not recommended for street cars, especially those that see frequent stop-and-go traffic which will cause surface glazing of the clutch.

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segmented kevlar
CHARACTERISTICS Same material and characteristics as solid kevlar above, but segmented (blocks or sections missing) for better heat dissipation. Segmented design may result in shuddering or "stepped" engagement when used in traffic situations. Material is uniform yellow/green and may look slightly fuzzy when new, alternating sections removed for segmenting.
USE Street-driven track cars up to 500hp, auto-x and heavy track use. Will take hard use, more intolerant of abuse (will overheat and not recover completely). Due to the unforgiving nature of Kevlar, it is not recommended for street cars, especially those that see frequent stop-and-go traffic which will cause surface glazing of the clutch.

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hybrid carbon/ceramic/organic
CHARACTERISTICS Organic material on one side and a segmented carbon or ceramic material on the other. The idea is that the organic side will help smooth the engagement, reducing the shuddering from the segmented side. Engagement is same as organic, but still with shuddering. Temperature and hp range is identical to organic. Carbon/ceramic side will wear flywheel or pressure plate surface faster and will wear out faster in traffic situations. Material is organic on one side (described above) and segmented or completely separate pucks (described below) on the other.
USE Can be used in same situations as standard organic. The "hybrid" design appears to be more of a marketing gimmick rather than an actual performance advantage. Some brands are poorly designed and wear unevenly due to flexation of the clutch disk. For examples of hybrid failure, click here.

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carbon/ceramic
CHARACTERISTICS Very high temperature materials, usually only found on multi-puck disks. Will accommodate 500hp+ Engagement is more abrupt. Will wear flywheel surface faster, especially in traffic situations. Carbon is slightly more durable and flywheel-friendly, ceramic has a higher temp range. Multi-puck design may result in slight shuddering or "stepped" engagement when used in traffic situations, although many users report completely acceptable operation. Material is any of several light hues - gray, pink, brown.
USE Street/strip applications for drag-racing and heavy track use cars up to 500hp. Will take very hard use, suitable for extreme-clamping applications.

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sintered iron
CHARACTERISTICS Extremely high temperature material. Will accommodate 700hp+ Engagement is on or off. Requires special flywheel surface. Material is metallic gray.
USE Strictly for high-horsepower endurance racing. With correct pressure plate, capable of extremely high clamping force. Engagement is like a switch, either on or off. Does not work well when cold. High-durability flywheel surface required, standard flywheels will be destroyed quick

 

[silvercoffin]

.

Back to our original question, how to choose? The answer depends on the answers to the two basic questions asked earlier regarding intended use of the car and power output. Based on the answers, this gauge will help the decision:



To repeat the important point, do not buy more clutch than you need.

A simple organic disk will handle a wide variety of use - including street use, auto-x, and even true racing. In fact, SCCA ITS racing rules require a standard OE-spec organic disk. UUC has tested organic disks to reliably handle up to 475hp in long-term street use. M3s regularly run through several auto-x seasons without problems.

A kevlar disk is a good choice for a heavily-tracked or road-raced cars, especially with forced induction.

Carbon/ceramic should be left to high-power cars that see lots of drag racing, or are dedicated track/drag cars.

Sintered iron clutch disks are strictly for endurance racing.

 

[silvercoffin]

more...

Organic Clutch
The Organic clutch is your basic stock replacement in either 10" or 10.5" and with either a standard pressure plate or "King Cobra" plate. Economical and well suited to the daily driver or show car.

Kevlar®/Organic Clutch
This clutch is a dual friction type with Kevlar®, and Organic surfaces designed for extra grab and high heat from high performance applications. Available in 10" or 10.5". Great solution for a track/street car.

Kevlar/Kevlar Clutch
Designed for long life and minimal wear, these clutches are preferred for the high performance, high torque applications. Also preferable in light weight cars to eliminate chatter. Available in 10.5". Best for Hot Rods, Cobra's and other performance applications.

 

[SicStang03]

If you don't mind I'm going to copy and paste that info into the how-to..

 

[silvercoffin]

...

of course... but I wish I could find someone that really knows about this stuff and how much break in is really needed.

I think I am only going to put about 200 city miles on this one and see how it does.

 

[NOXCUSES]

Hmm good info

 

[VirtualSVT]

I ran 1000 miles on mine before I got stupid on it.

I dunno if it helped.

 

[silvercoffin]

...

NOOoooo thats not what i want to hear LOL
The spec recommended 450 will be the best I can do... I am really thinking about just believing my mechanic and putting a few hundred on it and going to the track

 

[silvercoffin]

...

the spec 2 is a segmented kevlar clutch

 

[VirtualSVT]

NOOoooo thats not what i want to hear LOL
The spec recommended 450 will be the best I can do... I am really thinking about just believing my mechanic and putting a few hundred on it and going to the track

it was the hardest 1000 miles to go to.

I put it in the car then went to Ireland for a week then loaded the car on the trailer to move to Ohio where it was still topping out in the 60's.

It was very hard.

 

[SVTkel]

Interesting info. subscribing

 

[screamngdave]

silvercoffin, you have alot of good info there, and based on how you said you launch the car, I definately would not use a kevlar or sintered iron or sintered bronze clutch. Due to the heat and the stresses our cars place on the clutch, an organic clutch would not last long either. In all of our customers cars as well as my own, that require launching with the slipping of the clutch we use the centerforce lm series clutch disc and the old style centerforce pressure plate, both available as a kit from lethal performance. Give them a call and check it out and see what you think...
Dave

 

[screamngdave]

oops, dbl posted

 

[silvercoffin]

...

not sure about centerforce. I have heard they arent what they used to be quality wise..

That list is supposed to be ranked in order of least to most aggresive clutch material. Thats why i chose kevlar for now.

I went by the tq rating and figrued if a clutch is rated for less tq then it will slip more. Im not sure if that is necessarily true though.

I already have the stage 2 goin in this week, but i am trying to decide what to do if it doesnt work out. I could go with a spec stage 1 organic

The organics i had did last for a while. The last one was sitll in good shape when we took it out (FMS RACing clutch) . I went with the 3+ at that time only because I was hoping my shifting problems were clutch related. Turned out to be the trans. I'll definetely give lethal a call if I switch again.

 

[silvercoffin]

another write up

Organic Friction Material - All Mustangs came stock with organic friction material because of its excellent driveability characteristics. McLeod uses a unique friction compound in their organic disks. They have a higher heat capacity than both stock and other aftermarket organic disks. This is a good choice for most Mustangs used on the street, and even for racing. This material should be sufficient for 95% of Mustang owners with typical street-legal bolt on parts. The McLeod organic disks that we offer are all constructed with marcels.

Marcels - A clutch disk with marcel construction has the friction material of both sides backed by thin metal plates. Between these two plates are thin bowed pieces of steel (marcels), which act as springs when the disk is sandwiched between the flywheel and pressure plate. When the clutch pedal is let out, the marcels are flattened, and gradual engagement of the clutch is achieved. Marcels are more critical than a sprung hub in providing chatter-free clutch operation. Disks without marcels usually have poor driveability, unless the friction material has some compressibility (as sintered iron does). Over time, the marcels in a disk can lose their springiness and flatten out, increasing the likelihood of chatter.

Kevlar Friction Material - While this material typically has a lower coefficient of friction than organic materials at room temperature, it's coefficient of friction increases with elevated temperature. This means that as a Kevlar disk is heated during hard use, its torque capacity will increase, whereas an organic compound disk will lose torque capacity when its temperature is increased. Another advantage of Kevlar is its durability and resistance to wear. It will not burn as easily as organic compounds when slipped excessively. Burning causes permanent damage to the disc and a reduction in the coefficient of friction. The wear characteristics of Kevlar are significantly better than organic materials, making Kevlar a good choice for racing applications. The downside to Kevlar disks is that they have a high propensity to chatter when slipped. This makes them a poor choice for daily driven street cars, and weekend-only cars that are driven in stop-and-go traffic. Even though many other companies try to sell Kevlar clutch systems to street car owners, Maximum Motorsports wants to provide you with as much information as possible, and we do not recommend Kevlar clutches for extensive street driving. The Kevlar/organic McLeod disks that we list are all constructed with marcels, to reduce chatter as much as possible.

Sintered Iron Friction Material - Similar to Kevlar, sintered iron's coefficient of friction at room temperature is lower than organic friction material, but increases even more dramatically when its temperature rises. This is a very aggressive material, and therefore should only be used on steel flywheels or aluminum flywheels with a steel insert. While sintered iron is slightly compressible, it is not very flexible, so the McLeod sintered iron discs we list are constructed without marcels. This, combined with the high coefficient of friction when hot, causes sintered iron discs to provide only slight modulation. While McLeod sintered iron systems are reportedly subtler than other brands', they are still quite aggressive and we recommend them only for very high horsepower street cars, or all-out track cars. The non-marcel McLeod sintered iron disks will operate more smoothly than non-marcel organic or Kevlar disks because of the slightly compressible characteristic

 

[silvercoffin]

...

that one makes me more worried about kevlar!

Uhhhh less likely to burn but if you burn it you are screwed.. The chatter part sounds bad too...

If I cant slip it then I guess ill be stuck using the MT ET streets that i dont like. AT least ill have a trans that shifts now.

 

[silvercoffin]

Specs info
Stage 1
For bolt on naturally aspirated and mildly modified forced induction engines. Stock-like daily drivability and very good wear characteristics.

High clamp pressure plate, steel-backed and multi-compound woven organic material and high torque sprung hub and disc assembly, bearing and tool kit.

Stage 2 Kevlar
For all mild to moderately modified naturally aspirated and power adder engines. (Also good for stock power levels and spririted driving when good daily drivability and extremely long life are the goal.) Stock-like daily drivability and EXCELLENT wear characteristics.

High clamp pressure plate, pure Kevlar friction material and high torque sprung hub and disc assembly, bearing and tool kit.

Stage 2+
For all modified engines making more torque than the stage 2 can support. Maintains stage 2 feel for good daily drivability and offers very good wear characteristics, but provides a higher torque capacity. High clamp pressure plate, composite multi-friction carbon-kevlar material, high torque sprung hub and disc assembly, bearing and tool kit.

Stage 3+
For heavily modified street and race engines making more torque than the st3 can support. Offers good daily drivability and better manageability than the stage 3, with even better wear characteristics.

High clamp pressure plate, full-faced carbon metallic friction, high torque sprung hub and disc assembly, bearing and tool kit.


Weird that they dont say the stage 3+ is sintered iron but the couple of people that saw mine before it was installed said it was a sintered iron clutch.

 

[lloyyd]

You change clutches like I change wheels.

Let us know how you like that 2+. And if they say break it in 450 miles then that's what I'd do. I put about 470 on mine before I let loose on it.

 

[silvercoffin]

...

Yeah lol. I talk about it more than I do it.

I went from FMS Racing clutch to spec 3+ this summer...and wel...you know how much i love that clutch..lol

Now I am changing transmissions and it came 26 spline so I need anotehr clutch anyway..

I only went with a stage 2 rated for 589 tq