JB light flywheel

Duk996 · 11-03-2017, 03:40 PM

Anybody have any experience with this in their car? Not installing it but impact to drivability. I have always installed light flywheels in my bikes and it's made the throttle response much better and the bike therefore more fun.

spiderspider · 11-03-2017, 06:30 PM

I had a lighter weight single mass flywheel installed on my corvette before i sold it years ago. didn't like it. the chatter was annoying at idle and the noises at low rpm driving were terrible...it was like you were lugging the engine. so that's just my non-expert experience.

monterey · 11-03-2017, 09:24 PM

i agree, the chatter associated with a lightweight fly is not worth the trade off. i rather go with shorter gears like 3:73 with the differential.

deansbimmer · 11-04-2017, 08:53 AM

Your inquiry mentioned driveability. Driveability will suffer and depending on the setup, you'll likely get clutch rattle. Clutch engagement from a standing stop becomes touchy. Once moving and in the RPMs, the lighter flywheel will allow faster RPM adjustments when shifting etc.

A different animal from bikes.

spazzyfry123 · 11-04-2017, 09:00 AM

Could be fun at speed for quicker RPM changes in a purpose car (track car), but driving around town would not be fun in my opinion.

monterey · 11-04-2017, 10:30 AM

has anyone notice a change in their pickup after doing a clutch job in an 08. I hear they put in a heavier flywheel to elleviate the rattle.

deansbimmer · 11-04-2017, 11:47 AM

Quote:

Originally Posted by monterey

has anyone notice a change in their pickup after doing a clutch job in an 08. I hear they put in a heavier flywheel to elleviate the rattle.

This made me curious so I looked up the weights BMW per BMW.

Old flywheel/clutch assembly weighs 21.4kg
New flywheel/clutch assembly weighs 21.96kg

If those weights are accurate, I doubt anyone could tell a difference between the two.

decimation1 · 11-04-2017, 02:52 PM

Quote:

Originally Posted by deansbimmer

This made me curious so I looked up the weights BMW per BMW.

Old flywheel/clutch assembly weighs 21.4kg
New flywheel/clutch assembly weighs 21.96kg

If those weights are accurate, I doubt anyone could tell a difference between the two.

I noticed no difference after mine was replaced.

GT3fan · 11-04-2017, 03:57 PM

a true LWFW should notably improve throttle response and helps rev matching when downshifting. It does add noise/chatter at idle, but I consider it character to my gt3. Not sure if the results are similar with the s65, but worth considering if I ever need to replace my clutch.

Duk996 · 11-05-2017, 09:09 PM

Quote:

Originally Posted by AMG2M3

a true LWFW should notably improve throttle response and helps rev matching when downshifting. It does add noise/chatter at idle, but I consider it character to my gt3. Not sure if the results are similar with the s65, but worth considering if I ever need to replace my clutch.

What is meant by chattering? Does that mean it's grabby when starting off? If it's just noise what is making it?

deansbimmer · 11-05-2017, 09:36 PM

Quote:

Originally Posted by Duk996

What is meant by chattering? Does that mean it's grabby when starting off? If it's just noise what is making it?

Chatter is audible chatter. Think like a Ducati clutch, just not that severe. If you're a bike guy, this isn't much different of a concept.

Grabby clutches have to do with clutch selection, not flywheel. A lightweight flywheel will make it easier to stall from a standing start.

Duk996 · 11-06-2017, 09:47 AM

Quote:

Originally Posted by deansbimmer

Quote:

Originally Posted by Duk996

What is meant by chattering? Does that mean it's grabby when starting off? If it's just noise what is making it?

Chatter is audible chatter. Think like a Ducati clutch, just not that severe. If you're a bike guy, this isn't much different of a concept.

Grabby clutches have to do with clutch selection, not flywheel. A lightweight flywheel will make it easier to stall from a standing start.

Ack. I called JB and spoke with them about it before reading your post. He said the chatter is due to the backslash of the gears in the transmission essentially rattling due to the firing pulses. This depends on the backlash and weight oil used obviously and doesn't harm anything. Pretty much just like dry clutches in Ducatis like you mention; backlash. Anybody know specifically how our cars react?

deansbimmer · 11-06-2017, 10:32 AM

Quote:

Originally Posted by Duk996

Ack. I called JB and spoke with them about it before reading your post. He said the chatter is due to the backslash of the gears in the transmission essentially rattling due to the firing pulses. This depends on the backlash and weight oil used obviously and doesn't harm anything. Pretty much just like dry clutches in Ducatis like you mention; backlash. Anybody know specifically how our cars react?

Yes the chatter is from backlash but a V8 is already very smooth. There is very little time between pulses in a V8 compared to a 2 cylinder to allow much chatter. Our cars handle them well but it is a little more noisy than stock and requires you pay more attention from a standing start. Pretty typical.

Duk996 · 11-06-2017, 11:35 AM

Quote:

Originally Posted by deansbimmer

Quote:

Originally Posted by Duk996

Ack. I called JB and spoke with them about it before reading your post. He said the chatter is due to the backslash of the gears in the transmission essentially rattling due to the firing pulses. This depends on the backlash and weight oil used obviously and doesn't harm anything. Pretty much just like dry clutches in Ducatis like you mention; backlash. Anybody know specifically how our cars react?

Yes the chatter is from backlash but a V8 is already very smooth. There is very little time between pulses in a V8 compared to a 2 cylinder to allow much chatter. Our cars handle them well but it is a little more noisy than stock and requires you pay more attention from a standing start. Pretty typical.

Nice, the smoothness of all the cylinders makes sense. I don't mind the modulation part. I'm going to go for it. Thanks!

Duk996 · 12-07-2017, 01:01 PM

So I got a jbr lightweight flywheel and oem luk replacement clutch. I'm looking forward to installing it but am worried about it being a non sprung hub clutch. Any thoughts or experience out there?

deansbimmer · 12-07-2017, 01:56 PM

The factory clutch isn't a sprung hub either. Nothing to worry about.

Feels good man.

Duk996 · 12-07-2017, 02:24 PM

Quote:

Originally Posted by deansbimmer

The factory clutch isn't a sprung hub either. Nothing to worry about.

Feels good man.

I know, but the stock flywheel is! I'm probably overthinking this thing....

deansbimmer · 12-08-2017, 06:54 AM

Quote:

Originally Posted by Duk996

I'm probably overthinking this thing....

kerrit · 12-08-2017, 02:06 PM

Quote:

Originally Posted by Duk996

So I got a jbr lightweight flywheel and oem luk replacement clutch. I'm looking forward to installing it but am worried about it being a non sprung hub clutch. Any thoughts or experience out there?

post a review after it's on!

R3dliner · 12-08-2017, 02:10 PM

I had a single mass light weight flywheel with a stg2 south bend clutch on my G37 coupe. Stock's were a dual mass. There was a very loud chatter/rattle on low rpms but after a thousand miles or so it died down. I did notice the rpms did climb and drop much faster. chatter on idle did die down but was unbearable in the beginning. Also switched over to GTR fluid which I don't know if it helped.

Duk996 · 12-08-2017, 02:54 PM

Quote:

Originally Posted by kerrit

Quote:

Originally Posted by Duk996

So I got a jbr lightweight flywheel and oem luk replacement clutch. I'm looking forward to installing it but am worried about it being a non sprung hub clutch. Any thoughts or experience out there?

post a review after it's on!

I will! It's going to be a slow go though, the engine will be new and I will have to break it in...we should get a good understanding of how bad it is at idle though....which is where it's most annoying I guess.

VrooM3 · 04-22-2018, 02:15 AM

So any news on this? i wonder how the jbr lightweight flywheel and oem luk replacement clutch ended up turning out as i'm also considering this when the clutch is toast which may be in the next year as i'm nearing 81k miles.

11-03-2017, 03:40 PM	#1
Duk996 Second Lieutenant 245 Rep 256 Posts Drives: E92 m3 Join Date: Oct 2017 Location: west virginia iTrader: (0)	Anybody have any experience with this in their car? Not installing it but impact to drivability. I have always installed light flywheels in my bikes and it's made the throttle response much better and the bike therefore more fun.
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11-03-2017, 06:30 PM	#2
spiderspider Captain 312 Rep 657 Posts Drives: E90 M3 DCT, 991 C4S, E46 330i Join Date: Dec 2014 Location: Danville, CA iTrader: (0)	I had a lighter weight single mass flywheel installed on my corvette before i sold it years ago. didn't like it. the chatter was annoying at idle and the noises at low rpm driving were terrible...it was like you were lugging the engine. so that's just my non-expert experience.
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11-03-2017, 09:24 PM	#3
monterey Major 339 Rep 1,239 Posts Drives: 2008 M3 Join Date: Mar 2016 Location: United States iTrader: (1)	i agree, the chatter associated with a lightweight fly is not worth the trade off. i rather go with shorter gears like 3:73 with the differential. Last edited by monterey; 11-03-2017 at 09:33 PM..
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11-04-2017, 08:53 AM	#4
deansbimmer BimmerPost Supporting Vendor 3749 Rep 2,907 Posts Drives: 2011 E93 M3 Join Date: Nov 2014 Location: DFW, Texas iTrader: (17) Garage List 1988 BMW M3 [0.00] 2013 BMW M3 [0.00] 2011 X5M [0.00] 2011 BMW M3 [0.00]	Your inquiry mentioned driveability. Driveability will suffer and depending on the setup, you'll likely get clutch rattle. Clutch engagement from a standing stop becomes touchy. Once moving and in the RPMs, the lighter flywheel will allow faster RPM adjustments when shifting etc. A different animal from bikes.
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11-04-2017, 09:00 AM	#5
spazzyfry123 Lieutenant Colonel 4341 Rep 1,913 Posts Drives: Here and There Join Date: Jul 2013 Location: North Georgia Mountains iTrader: (1) Garage List 97 Toyota Land Cruiser [7.50] 16 Toyota Land Cruiser [10.00] 11 BMW E90 M3 Stripper [10.00]	Could be fun at speed for quicker RPM changes in a purpose car (track car), but driving around town would not be fun in my opinion.
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11-04-2017, 10:30 AM	#6
monterey Major 339 Rep 1,239 Posts Drives: 2008 M3 Join Date: Mar 2016 Location: United States iTrader: (1)	has anyone notice a change in their pickup after doing a clutch job in an 08. I hear they put in a heavier flywheel to elleviate the rattle.
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11-04-2017, 03:57 PM	#9
GT3fan First Lieutenant 239 Rep 356 Posts Drives: e90m Join Date: Dec 2016 Location: North Bay CA iTrader: (0)	a true LWFW should notably improve throttle response and helps rev matching when downshifting. It does add noise/chatter at idle, but I consider it character to my gt3. Not sure if the results are similar with the s65, but worth considering if I ever need to replace my clutch.
	Appreciate 0 Quote

12-07-2017, 01:01 PM	#15
Duk996 Second Lieutenant 245 Rep 256 Posts Drives: E92 m3 Join Date: Oct 2017 Location: west virginia iTrader: (0)	So I got a jbr lightweight flywheel and oem luk replacement clutch. I'm looking forward to installing it but am worried about it being a non sprung hub clutch. Any thoughts or experience out there?
	Appreciate 0 Quote

12-07-2017, 01:56 PM	#16
deansbimmer BimmerPost Supporting Vendor 3749 Rep 2,907 Posts Drives: 2011 E93 M3 Join Date: Nov 2014 Location: DFW, Texas iTrader: (17) Garage List 1988 BMW M3 [0.00] 2013 BMW M3 [0.00] 2011 X5M [0.00] 2011 BMW M3 [0.00]	The factory clutch isn't a sprung hub either. Nothing to worry about. Feels good man.
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12-08-2017, 02:10 PM	#20
R3dliner Lieutenant Colonel 935 Rep 1,930 Posts Drives: 18 M3 6MT Join Date: Mar 2016 Location: NYC iTrader: (5)	I had a single mass light weight flywheel with a stg2 south bend clutch on my G37 coupe. Stock's were a dual mass. There was a very loud chatter/rattle on low rpms but after a thousand miles or so it died down. I did notice the rpms did climb and drop much faster. chatter on idle did die down but was unbearable in the beginning. Also switched over to GTR fluid which I don't know if it helped.
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04-22-2018, 02:15 AM	#22
VrooM3 Private 24 Rep 52 Posts Drives: 2008 M3 Coupe Join Date: Jun 2013 Location: Vancouver iTrader: (0)	So any news on this? i wonder how the jbr lightweight flywheel and oem luk replacement clutch ended up turning out as i'm also considering this when the clutch is toast which may be in the next year as i'm nearing 81k miles.
	Appreciate 1 Assimilator1591.50 Quote