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Discussion Starter #1
What I would like to have:
aluminum flywheel (I know they have friction inserts.)
-Light weight
-SFI rating
-No less than stock torque rating
-Not a system like McLeod where you slap another piece on top of the stock flywheel in lieu of replacing flywheel with aluminum unit, which, in addition to not reducing weight, may actually increase it.
-Pedal effort means nothing to me. I don't care if it's "leg press" or "stepping on a pillow."

So far, I've looked around, I was hoping to find a nice LuK aluminum unit like I used on a car way back, but I don't think they exist.

One setup had a stated weight of 70 pounds. That seems a bit high, but it included everything. What I was concerned about was that the flywheel was not included, as it was a McLeod system that bolted on to the existing flywheel, IIRC. I've seen so many in my searching...
 

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The Bad Boys Garage units seem pretty rugged. I don't think its the unit that you want. I am curious to what a unit like you describe would cost. Maybe the number of M6 cars doesn't provide a good ROI for someone to build.
 
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Discussion Starter #3
I just like details that contribute to performance that are kind of unconventional, such as preferring to avoid adding extra mass, especially in rotating or reciprocating parts.

If I could get a close-to-zero mass clutch like a Pro Stock or road racing unit and find some way to make it work on the street, I'd like that, too.
 

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Discussion Starter #4
Ironically, the lightweight aluminum or a carbon fiber driveshafts I've seen are so small in diameter as to minimize any rotational mass reduction benefit, whereas a lighter flywheel and clutch is large enough in diameter that they will have more chance of perceptibly change the feel of the car.
for a given mass, a driveshaft would have to have a mass reduction of 100 pounds to match a mass reduction of about 11 pounds of a flywheel of 3x the diameter.
 

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I can understand the diameter difference being a huge contributor. When it comes to the clutch, you have the flywheel and pressure plate that would make a bigger impact if you cut the rotational mass like you're saying. I think the main factor of the aftermarket drive shafts were to provide a stronger unit.
 

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Discussion Starter #6
I can understand the diameter difference being a huge contributor. When it comes to the clutch, you have the flywheel and pressure plate that would make a bigger impact if you cut the rotational mass like you're saying. I think the main factor of the aftermarket drive shafts were to provide a stronger unit.
But, if that were the case, why not just use steel?
 

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I think there's always going to be some marketing for sales by making it lighter as well. Especially with the racers. If the weight reduction is close to 11 pounds, by itself is pretty low, but with those that are removing every ounce of dead weight it will add up and cut tenths of a second. In thinking, I would still want to buy a product that is lighter than one that is heavier.
 

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2020 Challenger Hellraisin Scat Pack.
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What I would like to have:
aluminum flywheel (I know they have friction inserts.)
-Light weight
-SFI rating
-No less than stock torque rating
-Not a system like McLeod where you slap another piece on top of the stock flywheel in lieu of replacing flywheel with aluminum unit, which, in addition to not reducing weight, may actually increase it.
-Pedal effort means nothing to me. I don't care if it's "leg press" or "stepping on a pillow."

So far, I've looked around, I was hoping to find a nice LuK aluminum unit like I used on a car way back, but I don't think they exist.

One setup had a stated weight of 70 pounds. That seems a bit high, but it included everything. What I was concerned about was that the flywheel was not included, as it was a McLeod system that bolted on to the existing flywheel, IIRC. I've seen so many in my searching...
No experience with Hellcat fitted with aluminum/light weight flywheels and only 2nd hand experience with other brand of cars but there can be driveability issues with the light weight flywheel (LWFW) fitted.

The car becomes harder to move off from a stop and RPMs drop during shifts making it harder to shift smoothly.

The engine can gain RPMs quicker but with the Hellcat this just means the tires spin more. That is even with the stock flywheel the car is severely traction limited under hard acceleration.

The engine may not idle as smoothy with the LWFW fitted. The engine controller may not be able to accommodate the LWFW. With a rougher idle this can subject the crankshaft to cam drive system to more stress.

As for pedal effort there is the effort but also the feel. Have not driven a Hellcat with an aftermarket clutch fitted but some years back I drove a couple of cars fitted with high performance clutch and not only was the pedal effort high but the clutch feel was practically non existent. The clutch was like a switch. Off or on.

My advice is if the engine is stock to stick with the factory clutch/flywheel setup.
 

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My car came with a Bad Boyzz Garage clutch. I like the way it feels, but it's super noisy when disengaged. It's supposedly normal, but everyone around you thinks your car is Fd up..
 

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Discussion Starter #10
Thanks for the input guys!
I found this item in my searching. 1010 ft-lbs of torque capacity at the crank. To transmit torque while keeping polar moment under control, it has twin nine inch friction disks, which GIVEN THE EXACT SAME MASS would provide 1.493 times as much inertia/momentum as an 11 inch disk. Obviously, this is not precisely the case, as the extra diameter of an 11 inch unit is made up of some of the lightest parts of the overall clutch pack, but, hey it's still free hp under acceleration that is devoted to moving the car instead of spinning up the clutch.

566755

So the engine turns the flywheel, the clutch plates, and the red clutch diaphragm spring body, and they, in turn, bear upon the twin friction plates that drive the transmission.
I'm not a fan of the flywheel design of the M6 trans. The ring gear is quite far, along the rotational axis, from the friction surface, requiring a lot more mass to have a ring gear held in that strangely chosen position than would be required if it was coplanar with the friction surface or close to it. It takes less mass and engineering to spin a disk at 8000 rpm than to spin a bowl at 8000 rpm, because anything round that you spin at high rpm is trying to BECOME a disk.
 

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The price on that unit seems pretty reasonable compared to the others.
 

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Discussion Starter #12
I thought so, also.
I like the holes in the flywheel, also, as they allow/facilitate/cause air circulation better than just a blank-faced plate would.
I can also tell you, just by the size of everything, and the flywheel material (12-13 pounds, from what I've found) there is no way this assembly weighs 70 pounds like another I've seen. I'm good with 1010 ft-lbs, also. I will have to find the rev limit, also.
 

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Discussion Starter #14
Mantic pic of Mantic versus McLeod:

The "buckle under deceleration" thing was of concern to me because partially due to the "stirring a bucket full of rubber" shifter feel, I have downshifted three gears instead of one and REALLY revved up the drivetrain.

Yes, a Barton shifter or some means of stiffening the shifts up is on the menu, also. Since one is not supposed to drive wtih one's hand on the shifter anyway, (race drivers only touch shifter to shift) I am not worried about vibration from putting in stiffer bushings, but that's down the road a bit.
566838
 

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The Mantic really looks like a much better setup. I had the Barton in my Hellcat and loved it. You can adjust the fore and aft as well as side to side to adjust where you want it positioned. It has more of a notchy or more precise feel. If I were to own an M6 again, Barton would be my first choice. I have no experience with the Hurst or other brands and this is based on how much I liked the Barton.

Based on other's experience, I used Loctite on the bolts for the Barton and never experienced any loose bolts.
 

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Discussion Starter #16
My car came with a Bad Boyzz Garage clutch. I like the way it feels, but it's super noisy when disengaged. It's supposedly normal, but everyone around you thinks your car is Fd up..
Another reason I like the Mantic, from what I've seen. It has small springs on the edges of its billet steel between-the-clutch-friction-material-things that push the plates a bit apart in a uniform manner when it is disengaged, so no rattle.
Also, they have a triple-disk unit rated for 1515 hp:
 

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Discussion Starter #17
I do have a concern regarding the design.
566974


What is holding the clutch plates on the flywheel is a collection of eight bolts and eight aluminum stands. The diaphragm spring housing is not directly attached to the flywheel. So, evidently the flywheel drives the eight bolts which drive the plates via the aluminum stands, unless they are steel, of course, but having torque resisted by a bolt that is experiencing most of its stress in single shear is not something I would regard as a recipe for long-term reliability.

In fact, single shear is one of the worst-case scenarios, especially if it is combined with an additional bending load from leverage of the furthest component, namely the spring housing, and the plates as one continues further from the flywheel.
Evidently, the clutch steel plates slide up and down these stands during normal operations. This is a source of wear.

Assuming the maximum torque of the three-disk version, 1515 foot-pounds, with six friction surfaces total, one of which is the flywheel and does not count in the pressure places on the stands, so 1515/6X5 =1262.5 foot-pounds experienced by the eight bolts and stands. or 157.1825 foot-pounds dedicated to each of the 22.5 degree slices of the assembly. Since the eight stands are about 10 inches in diameter in their bolt circle, the torque is one foot/10 inches X 157.1825=189.375 pounds of force exerted on each stand at the rated torque. This is not a static load, but it is sliding up and down that stand every time the clutch is engaged.

The McLeod has a one-piece stamped cover, that experiences no friction or movement. However, the intermediate clutch disk still has to move a bit during clutch disengagement and engagement, and it is supported by three bolts, evidently, but they are not in single shear, but have one end secured to the flywheel or whatever McLeod bolts thereto, and the other end supported by the stamped clutch cover which is bolted to the flywheel, so on the McLeod unit, the bolts undergoing the most stress are mounted in double shear, which is the ideal shear situation, and though there is movement up and down said bolts of the clutch disk, it is taking only 1/2 of the torque (the other half borne by the clutch housing and the flywheel, which is retained with separate, shorter bolts) and the parts experiencing said sliding are made of steel.

3/8 as many surfaces, each surface (given same torque values) would experience 303 pounds of force at rated torque. on a smaller area, as there is only one additional disk in the Mcleod.

Conclusion: my main concern on the Mantic or similar designs with a pressure plate floated off the flywheel standing only on bolts with stands around them is that the aluminum stands would wear over time and/or loosen, being fastened in single shear and for the Mantic, bolted into an aluminum flywheel.

I like the idea of an aluminum flywheel, but not combining single shear bolt mounting with said aluminum.

I would think a single-piece stamped or billet aluminum pressure plate bolted directly to the flywheel would be more desirable, with the clutch disks moving on hardened steel bolts/rods/whatever that are mounted in double shear with said pressure plate.

I don't know of any long-term reviews of either brand, though. I could do some more research. I think it is possible that through-bolting the eight stands (as in putting an additional nut on the far side of the flywheel in addition to the existing threads in the flywheel and using high-strength steel stands could provide more clamping power and thus more stabilityfor the stands and greater longevity.
 

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Discussion Starter #18 (Edited)
I also think the flywheel is the place you primarily want to focus on weight reduction, as it is a "dumb" piece that has little function other than just being a friction source for the clutch disks.
The pressure plate ass'y, however, has multiple functions and force vectors acting simultaneously, so extra weight there (such as better design and construction of steel) is not a major drawback, especially when combined with the relatively smaller diameter.

I think ACT has aluminum flywheels, but one would have to examine the dimensions of the friction surface.
 

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Discussion Starter #19
Found this one, too: the RPS carbon clutch, in three or four plate versions:
567194


As you can see from the exploded view, (excuse the term) ALL the friction surfaces of the RPS are carbon. There is no carbon-on-steel, which is rather unique.

Also, the flywheel is billet steel, as are the intermediate disks. Due to small diameter, weight is kept to 38 pounds overall, and the pressure plate bolts DIRECTLY to the flywheel, which eliminates what I consider to be a flaw of the Mantic, the

This RPS gem is in use in applications to 10,000 RPM, according to Carolina Clutch.
Having done some math of the force involved to keep a 38-pound (stated weight of an RPS) in one piece at 11,000 RPM, I seriously question my desire to use an aluminum flywheel. I guess I could rig something up to spin it to failure and test it myself, but I would rather know from the manufacturer.

11 kRPM is Pro Stock territory, for sure, and they use clutches as small as 6.25 inches.
Now, sintered iron friction material is The choice of pro racers these days, but it's grabby as heck and I am not sure of the longevity. I wonder why no one makes a carbon/carbon flywheel. Maybe they have those in F1.

However, if he finds that it's good to 11k, the RPS will most likely win my personal contest for clutch preference, just like the Nittos did due to being (Y) rated. NO amount of money saved is going to make me feel better about an RPM-cracked clutch.


For the Viper, I sent in inquiry to ascertain if it can be used in the Hellcat. We'll see if they bother to respond:
 

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Discussion Starter #20
My car came with a Bad Boyzz Garage clutch. I like the way it feels, but it's super noisy when disengaged. It's supposedly normal, but everyone around you thinks your car is Fd up..
From carolinaclutch.com's blurb on the Hellcat clutch:
"Our liberal use of Formula One inspired carbon-carbon friction material results in a lightweight clutch with unmatched long term durability while also being a very quiet clutch unlike many multi disc clutches available on the market."
 
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