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JWT HD Clutch & Lighweight Flywheel Impressions

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Old 11-18-2008 | 02:37 PM
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Yea a lot of wheel hop, didn't do it before though on the stock clutch, started happening once I got this clutch
Old 11-18-2008 | 07:13 PM
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Originally Posted by JZK
Yea a lot of wheel hop, didn't do it before though on the stock clutch, started happening once I got this clutch
Clutch isn't going to cause wheel hop to worsen. The only thing likely is that the clutch is grabbing in more quickly and breaking traction more quickly, or that the flywheel being a single mass is not allowing for the absorption of the vibration that causes wheelhop.

Wheelhop is an oscillating force (essentially) and with the dual mass flywheel some of that could have been absorbed (maybe?), with the new clutch/flywheel you get much more direct delivery of the power with less absorption.

If you are getting wheel hop also, check your rear shocks, check your tires for proper inflation, and stop doing whatever it is thats causing it. Wheel hop is EXTREMELY hard on your drivetrain:
The diff gears, tranny gears, clutch components, crankshaft, tranny mounts, engine mounts, half shafts, and flex joints in the driveshaft all get a lot of abuse from it. Not that any one component can break, its best to avoid it, or stop accelerating if it occurs.
Old 11-18-2008 | 10:40 PM
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Originally Posted by Peak350
Clutch isn't going to cause wheel hop to worsen. The only thing likely is that the clutch is grabbing in more quickly and breaking traction more quickly, or that the flywheel being a single mass is not allowing for the absorption of the vibration that causes wheelhop.

Wheelhop is an oscillating force (essentially) and with the dual mass flywheel some of that could have been absorbed (maybe?), with the new clutch/flywheel you get much more direct delivery of the power with less absorption.

If you are getting wheel hop also, check your rear shocks, check your tires for proper inflation, and stop doing whatever it is thats causing it. Wheel hop is EXTREMELY hard on your drivetrain:
The diff gears, tranny gears, clutch components, crankshaft, tranny mounts, engine mounts, half shafts, and flex joints in the driveshaft all get a lot of abuse from it. Not that any one component can break, its best to avoid it, or stop accelerating if it occurs.
Gotcha. Thanks peak.
Old 11-18-2008 | 10:48 PM
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Oh and the vibrations from the clutch... I've noticed that it only does it when the tranny warms up. I'm thinking it's the tranny fluid since I had a rear main seal leak causing tranny fluid to build up in the bottom. I replaced the seal. The shop (who installed my clutch and flywheel) refilled the tranny fluid back up. Now I'm thinking its the tranny fluid causing the vibrations because the viscosity is too thin after it heats up. Therefore, I'm going to the dealer tomorrow to buy the same tranny fluid that came with my car, hopefully this will fix the vibrations, I'll fill you in.
Old 11-19-2008 | 05:13 AM
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How about the limit of the clutch? is it good for around 500whp with hard driving?

Last edited by midz350; 11-19-2008 at 05:18 AM.
Old 11-19-2008 | 06:11 PM
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Originally Posted by midz350
How about the limit of the clutch? is it good for around 500whp with hard driving?
I think its good to around that, the JWT clutch is the same in the HR and DE, so it should hold the same in both if you want to look at what people have made powerwise in DE cars.
Old 11-26-2008 | 10:11 AM
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Stock flywheels have a tension system built into them that allows the face of the flywheel to pivot seperately for a few degrees from the rest of the body. This is why the OEM clutch is quieter, not so much because it's aftermarket
Old 11-26-2008 | 12:10 PM
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I just got JWT clutch/flywheel installed. Noise isn't a big deal. I also had headers, TPs, Jic ypipe, and Apexi N1 exhaust installed. There is a little chatter in neutral. I still have to break clutch in before I can see a real diff. over stock. I love the way my Z sounds now. If anyone is looking for a good tuner in South Carolina, check out AVengineered.com. Anthony Verma in N. Charleston is awesome. He also installed the reflash from Technosquare. I'm blessed to have found him. Found him by accident on a friends Honda forum. More than just a mechanic. This guy has a degree in mech engineering. While he treats this stuff like science, he is still very personable. And reasonable. 297 hp at the flywheel!! OK I'm finished gloatin for the moment.
Old 11-26-2008 | 10:28 PM
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Originally Posted by powermark
Stock flywheels have a tension system built into them that allows the face of the flywheel to pivot seperately for a few degrees from the rest of the body. This is why the OEM clutch is quieter, not so much because it's aftermarket
I'm aware, I broke that part of my stock flywheel and the mating surface shoved forward.

The weight has a large part to due with the rattle reduction, it doesn't allow the synchros in the transmission to rattle around as much.

BMW guys have run different fluid mixes to varying success, but basically light weight = more rattle.
Old 12-02-2008 | 10:29 PM
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So I've just came to realize that because the JWT flywheel is half the weight of the stock one, I need to shift earlier. A lightweight flywheel is good for acceleration, however once it gets to the 7000-7500 rpm range, it just stops pulling. I literally tested it out with a friend about an hour ago. I raced him 40-140 shifting at 7500 every gear and were were dead even at 140. We did the same exact race, same exact direction and same exact road, however i shifted at 7000 every gear and i had him by about a car and a half at 140. interesting. o_o
Old 12-03-2008 | 06:01 PM
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Originally Posted by JZK
So I've just came to realize that because the JWT flywheel is half the weight of the stock one, I need to shift earlier. A lightweight flywheel is good for acceleration, however once it gets to the 7000-7500 rpm range, it just stops pulling. I literally tested it out with a friend about an hour ago. I raced him 40-140 shifting at 7500 every gear and were were dead even at 140. We did the same exact race, same exact direction and same exact road, however i shifted at 7000 every gear and i had him by about a car and a half at 140. interesting. o_o
Not sure if the results are from the flywheel or elseware.

Car should still pull a lot more in a lower gear, the gearing advantage is significant.
Old 12-05-2008 | 07:47 PM
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is it bad to drive on the highway during the break-in? just wanna make sure since I'm gonna have mine install soon
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