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      03-09-2012, 07:04 PM   #1
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Lightweight Flywheel pros/cons

There hasn't been a lot of info regarding lightweight flywheels posted on these forums and I was hoping to get some more info.

What are some of the advantages and disadvantages of a lightweight flywheel? How do they compare to the dual-mass flywheel that we have in our cars already?

I'm talking to OS Giken to see if we can get an option for our cars. Thanks in advance.
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      03-09-2012, 07:16 PM   #2
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Lightweight flywheels let you rev up more quickly, but they also drop revs more quickly and tend to be noisier (clutch chatter/vibration).
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      03-09-2012, 07:32 PM   #3
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I was looking at going lightweight when my dual mass started slipping, I was advised strongly against it as they had swapped one out before and the person came back days later saying it was too noisy.

I'd like to try one to see how it feels, but couldn't justify the cost of having to replace it with a DMF if I didn't like it so I got a new DMF
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      03-09-2012, 08:05 PM   #4
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JB racing already makes a really good one.

Cons, can make more noise and will change the way the car shifts, which may be in a positive way or a negative way depending on how you drive.

Pros, slightly less parasitic loss, JB racing one has replaceable surface which is nice for people needing to do clutch changes a lot. Not as expensive as an OEM one.


If you don't already know the pros and cons though, then you probably don't need it, because if you were having a problem with what it solves, you would already know what it does to solve it.
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      03-10-2012, 09:43 AM   #5
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SPEC 8lb lightweight fly wheel is noisy as hell. Very chatty.

Pros: Its spins up nice a smooth very quickly.
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      03-10-2012, 12:37 PM   #6
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You'd notice the weight reduction in 1st gear the most, and maybe a bit in 2nd gear
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      03-12-2012, 03:32 PM   #7
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I went single mass light weight in my 02 VW Golf IV turbo, it has a dual mass stock. It revs waay faster and applyies the power better in every gear. It does not change the way the car drives or make any more noise than the stock did. I will do to my z4mc when funds are available.
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      03-13-2012, 03:38 PM   #8
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My 2006 MC has the JB flywheel and clutch and it is a little chatty, plus a little grabby, but once you get used to it, it isn't too bad. You do have to shift a little more aggressively/faster because the revs drop fast. Because of this it is harder to drive smoother.

But it does rev quicker. I have to pay attention or I am bangin' into the rev limiter in 1st and 2nd.
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      03-31-2012, 11:28 AM   #9
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Keep in mind UUC is trying to sell you a lightweight flywheel:

How a lightweight flywheel works

How to choose a clutch

What actually causes "lightweight flywheel noise" / "gear rattle" / "gear lash noise"

How to reduce BMW Transmission Rattle / Gear rattle / Gear lash noise

Is there any torque loss with a lightweight flywheel?
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      11-23-2012, 10:10 PM   #10
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bump, any one recently change over to a LTW flywheel?
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      11-24-2012, 12:31 AM   #11
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Anyone do weighing for said LTW flywheels? How much lighter are the aftermarket ones compared to the OEM DMF? Wonder if it's worth the hassle

For my old MR2 turbo, it was a no-brainer, as OEM was quite expensive for such an old and rare care. I upgraded the motor and turbo and had a lot of other supporting mods including LSD diff, beefed up axle cages, etc. and when it came time to drop the transaxle, I decided to get a pretty hardcore setup: an ACT stg. 3, 6-puck unsprung clutch kit with heavy duty pressure plate and Fidanza LTW flywheel, as well as a GFB LTW crank pulley. Needless to say, the car accelerated quite flawlessly
The ACT stg. 3 clutch kit was supposed to be for drag racing, and coupled with the LTW flywheel, it took some getting used to. The bite was VERY quick and harsh, but allowed for very quick shifts. I did have a bit of clutch chatter, but it seemed to have come from the older throwout bearing.
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      11-24-2012, 05:07 AM   #12
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Don't you want to pair a sprung hub clutch with a single mass flywheel, or an unsprung/solid clutch with a dual mass?
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      11-24-2012, 02:29 PM   #13
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Quote:
Originally Posted by pokeybritches View Post
Don't you want to pair a sprung hub clutch with a single mass flywheel, or an unsprung/solid clutch with a dual mass?
I'm not sure if all applications are the same, so I can't really comment. All I know is that for the Z4M, I feel as if the revs drop quick enough as-is. I don't think I'd change the OE DMF unless for power-holding purposes (in which case I'd need to get a blower put in first ).
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      11-24-2012, 06:21 PM   #14
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Quote:
Originally Posted by DSC_OFF View Post
bump, any one recently change over to a LTW flywheel?
My friend who works with TCK has a LTW Flywheel (single mass). IT's a JBR with a M5 Clutch disc

Holy crap...what a difference. I drove his car multiple times (street and auto-x) and my head gets thrown back into the seat.

And this is from an E36 M3. If I wanted to turn my car into a track car (I have plans for another car to do that duty), I would get one instantly.

Chatter was present, but only at idle. The car was changed completely, it jumped off the line, and into 2nd gear was amazing. I'm still shocked it threw me into the back of the seat...driving my car into 2nd is all just "meh" now.

lol.

But seriously, LTW Flywheel
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      11-30-2012, 02:08 PM   #15
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I recently put the UUC lightweight flywheel and oragnic clutch in my 2007 z4mc!!!!

The flywheel itself it ALOT lighter but the m5 pressure plate they use is heavier so it is not exactly as light weight as you would think.

Overall I have not seen any drivability changes with cruise controll or any other ordinary driving changes. I do get some gear lash chatter with the cluth out in nuetral so I am going to do the UUC recomended fuild change to help with this, though it is not really that bad.

As for the performance change OMG lol

I am just over 650 miles on this clutch so I have not played with it much but rolling in second at 4k RPM if you step on it, it will spin the tires (275/35 supersports).

If you do a launch which I have only done one, as I continue to baby it a little longer you get very little wheel spin and the car is a rocket. Because it gets the weight trasnfered nice and fast.

I also put it a set of red UUC poly engine and transmission mounts, (will post a pic) the stock driver side mount was craking and easily defleted with fingers at just 60k miles.

The trans mounts are bolt-through and I think with having them maybe a little over torqued etc I am putting in the isolated mounts this weekend to get rid of the vibrations the bolt-through are causing.

Other than that I would never go back to the dual mass unit. It was out of spec in play @ 60k miles but did not really give any indications anything was amiss untill I put the mounts in my car. It sounded like flicking one of those spring door stops when taking off in first gear while in traffic. It had a bad throw out bearing as well but was not making any bad noises for that.

I will get with txz4 so we can compare the diffrences (we both have 2k7 z4mc in TiSilver) in person going back and forth from one to the other. Maybe do a video as well.
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      11-30-2012, 02:10 PM   #16
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Quote:
Originally Posted by davesz4mc View Post
I will get with txz4 so we can compare the diffrences (we both have 2k7 z4mc in TiSilver) in person going back and forth from one to the other. Maybe do a video as well.
This would be much appreciated.
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