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ACTman

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My experience is anecdotal, at best, but I really liked the 6puck ACT clutch in my 240sx. I beat on it mercilessly and it held up well. ~$1100 for the ACT plus flywheel isn't bad.

Dirk, for the layman and someone new to 4x4s, can you expound on the results behind the steering wheel between the street and promass flywheels and why the weight varies so much between stock and other manufacturers who have flywheels up to like 67lbs? IIRC the stock flywheel is something like 48lbs whereas the street and promass are 29 and 41lbs respectively according to the one-sheet.

With all that said, I forsee myself installing one of the ACTs, almost certainly laying on my back cradling my transmission on a floorjack.. wouldn't be the first time though.
The stock flywheel weighs 29.5lbs and the whole stock clutch/flywheel assembly weighs 49.5lbs. For a comparison, the important number is the moment of inertia (MOI), not weight. I haven't tested the StreetMass behind the wheel, but the heavier ProMass feels really well matched to the vehicle in my opinion. We knew some people would be nervous about a big change in inertia so we opted to offer two weights. With our clutch kit and the StreetMass flywheel, it adds about 25% more inertia and the ProMass is about 50% if I recall.

It's hard to explain the behind the wheel experience. The drivability and rev-hang (stupid electronics) and stock weight seemed a bit weird which is why we opted to increase inertia even with our StreetMass. The best thing I can say about driving with the JP6-HDSS kit (includes the ProMass flywheel) is that you don't find yourself thinking about the clutch. In my opinion it just feels natural for the vehicle. With the added inertia, it will make it more enjoyable and forgiving off-road and/or especially towing.
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GCoop

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<edit>
never mind. ill squelch my initial thoughts.
 

seven30

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With our clutches, we have two options for flywheels. Both are solid flywheels and use a conventional type 11" clutch with a torque capacity of 480ftlbs (if using street discs). No change in the hydraulics required. We also have a step by step install video. Here is a press release:
https://www.advancedclutch.com/arti...or-JEEP-Wrangler-JL-Gladiator-JT-Applications.
Be neat to have a dual plate option with solid flywheel.
I have not had any issues with my clutch at 38k except for the idiot dual mass flywheel requiring a lot of finessing at near idle to avoid stalls.

Edit: nearly half those miles were pulling loaded trailer.
 

ACTman

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Be neat to have a dual plate option with solid flywheel.
I have not had any issues with my clutch at 38k except for the idiot dual mass flywheel requiring a lot of finessing at near idle to avoid stalls.

Edit: nearly half those miles were pulling loaded trailer.
There are advantages to a dual disc clutch design. I just don't see any of them making sense for the Jeep JL/JT.
 

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redriderjf87

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Being that this is a safety issue and Jeep has no remedy, I really want to have Jeep reimburse me towards a correctly designed aftermarket clutch/flywheel
 

ACTman

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Well the light pedal is the only one I know of.
I don't see that as an advantage. It feels terrible on the Jeep IMO. It is marginal new, but after twenty thousand miles, the pedal feels awful. I will explain other advantages and tradeoffs in another thread later.
 

IanNubbit

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I don't see that as an advantage. It feels terrible on the Jeep IMO. It is marginal new, but after twenty thousand miles, the pedal feels awful. I will explain other advantages and tradeoffs in another thread later.
I saw your post in the JL forums saying you use a modified Jk pressure plate (essentially) as far as design. My wide has a manual JK, she refuses to drive the JT because she says it feels like the clutch is sticking to floor with how light it is. With your clutch, does it have that conventional constant pedal pressure all the way to the floor, or does it get soft at the bottom like stock? I should not I have removed the pedal return spring to minimize this “pedal stick” feel, but made no real difference
 

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seven30

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I don't see that as an advantage. It feels terrible on the Jeep IMO. It is marginal new, but after twenty thousand miles, the pedal feels awful. I will explain other advantages and tradeoffs in another thread later.
Interesting. Mine improved significantly but took nearly 5k to bed in. They seem to be all over the map from all the posts.
 

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Let's see if this graph answers that for you. These are actual pedal tests done at ACT.

Jeep Gladiator Clutch Recall (2/23/23): Clutch Pressure Plate May Overheat -- Affecting 70,000 Manual Jeep Wranglers and Gladiators JL Pedal graphs
I think it does? At least show it stays nominal after the actuation point which is good and predictable. Personally I don't fully understand this graph. How is pressure (I think we are measuring pressure) measured. Both up and down. it the left measurements PSI, or ft/lbs, in/lbs? is the bottom inches of travel, mm, cm, just placeholder numbers? I can gather, stock is very soft, I cant tell what up from down stroke is though. I can also gather ACT is linear in force with a nearly flat plateau after grab point compared to more exponential of a wave with stock and drop off after grab. Maybe you could explain better?
 

ACTman

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I think it does? At least show it stays nominal after the actuation point which is good and predictable. Personally I don't fully understand this graph. How is pressure (I think we are measuring pressure) measured. Both up and down. it the left measurements PSI, or ft/lbs, in/lbs? is the bottom inches of travel, mm, cm, just placeholder numbers? I can gather, stock is very soft, I cant tell what up from down stroke is though. I can also gather ACT is linear in force with a nearly flat plateau after grab point compared to more exponential of a wave with stock and drop off after grab. Maybe you could explain better?
The travel is measured in inches from left to right. The scale top to bottom is the effort (load) it takes to press the pedal measured in pounds. The higher curves are when you are pushing down on the pedal, the lower curves are the return force against your foot as the pedal comes up. Can you see where the stock (black line) pushes less that 2lbs on the return stroke? That is what I mean by awful.
 

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The travel is measured in inches from left to right. The scale top to bottom is the effort (load) it takes to press the pedal measured in pounds. The higher curves are when you are pushing down on the pedal, the lower curves are the return force against your foot as the pedal comes up. Can you see where the stock (black line) pushes less that 2lbs on the return stroke? That is what I mean by awful.
Okay so I did understand it. Pressure going back is a good way to explain and I get it now fully. ~2 lbs on return is actually horrible, totally get why my wife thinks its "sticking to the floor" compared to the JK
 

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Got the truck back today with the Centerforce dual friction clutch/flywheel and hydraulics installed. Apart from the fact that the dealership fleeced me on the labor, everything so far is great. I drove the truck for about 40 miles (both city start/stop and highway). The dual friction feels heavy, but not overly so, and has none of the vagueness of the stock clutch. The effect of the heavier flywheel is also clearly there - truck does not stall when going uphill on 1st or 2nd gear without throttle. The stock clutch could never manage to do that. So far, I am quite happy with the centerforce kit - I imagine it will make off-road driving much better too.

I will be submitting for reimbursement to FCA Would be good to get back some of my $3K that this ordeal has cost me. I have kept the stock parts and if anyone is interested I will post photos. I am not an expert mechanic, but I am not a newbie MT driver either. I put 200K miles on my 2000 nissan frontier and never needed to replace the clutch, and never felt it slip even when towing, and so I am quite certain it is not my style of driving that caused any of this. Given my experience, I'd advice anyone who felt the stock clutch slip even a little, to check for heating and if they notice that to replace with a solid aftermarket part ASAP. Your safety is not worth waiting for whatever haphazard solution FCA is bound to come up with. They already showed how much they really care with the "software" update fix - I don't have much faith that they will come up with a robust/safe solution this time around.

Thanks to StevenInOrlando and especially to BrianKay for the advice. I am crossing my fingers that the the techs bled the clutch correctly so that I will have no more problems.
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