[dAng! E90]

I am about to purchase a SPEC clutch for my 335i. They have an option for a 14lb flywheel that is rebuildable. Just wanted to get some opinion on whether or not to do a lightweight flywheel? Any opinions are much appreciated!!!

[jpsimon]

if you can get over the rattle then it's great. I've had the stage 3 clutch+lightweight flywheel for 10's of thousands of miles now and it performs fantastic... you just need to get over the noise (i hold the clutch down at stop lights).

[cstavaru]

My opinion is that it is mandatory to either resurface or replace the flywheel when you replace the clutch, if you want it to last. If you could find a shop to resurface your existing flywheel I can't see a reason why you should spend the money on a lightweight flywheel that could chatter a lot and diminish the "daily driver" and "sleeper" status of a 335i. I think that a better option is to spend $700 on a new OEM flywheel.

[Bakeme521]

I love the one I just got from clutchmasters. The way I see it is if you have the transmission out and you are replacing the clutch you either need to resurface it or change it anyways, so why not upgrade? The chatter isn't that bad, but I do find myself holding down the clutch to shut it up at stop lights. Honestly though, if the radio is up a little or the AC is blasting you can't hear it. For me, the pros surpass the cons.

[99three]

Does anyone know the weight of the stock FW vs the light weight FW? As I recall a lighter FW=quicker spool up! I'd love to hear what all the "chatter" is about....a sound clip would be a great deciding factor. Are we talking marbles in a coffee can sound?

[#Tee]

Installed lighten fly wheels on many other previous cars including my own. The owners had a case of the placebo effect. I didnt notice crap and i even kept telling myself....it revs quicker!?? fast forward 100k miles later replaced it with an oem wheel and the car felt the same.

To sum up just run the lighten wheel so you can tell yourself its faster.

[jpsimon]

Originally Posted by 99three

Does anyone know the weight of the stock FW vs the light weight FW? As I recall a lighter FW=quicker spool up! I'd love to hear what all the "chatter" is about....a sound clip would be a great deciding factor. Are we talking marbles in a coffee can sound?

If I remember correctly the stock flywheel assembly is 35lbs give or take.. so it's a sizable difference. here are a couple videos of mine showing the shatter

[#Tee]

Clutch chatter isnt something that you can hear at idle or in motion. Its a combination of increased pressure plate force + kevlar/friction disc material type/puck style/unsprung disc. Its a sticky vibrating grabby sensation as the power train engages. You and the whole car will feel it.

[Former_Boosted_IS]

The whole LWFW chatter could be eliminated if we could raise the idle to like 900 rpms.

[bulldog_yyc]

spec blows

[jpsimon]

Originally Posted by bulldog x6

spec blows

does it? because my setup has been absolutely flawless for probably 30,000 miles or so... and it's what shiv has been running with the upgraded turbo (same stage as me) with no issues at all.

It all comes down to installer competence. many bad reviews of any clutch is due to install error

[jpsimon]

Originally Posted by StretchNpoke

Clutch chatter isnt something that you can hear at idle or in motion. Its a combination of increased pressure plate force + kevlar/friction disc material type/puck style/unsprung disc. Its a sticky vibrating grabby sensation as the power train engages. You and the whole car will feel it.

that's not what we're talking about, with these lightweight flywheels there is a lot of noise at idle.

[bulldog_yyc]

Originally Posted by jpsimon

does it? because my setup has been absolutely flawless for probably 30,000 miles or so... and it's what shiv has been running with the upgraded turbo (same stage as me) with no issues at all.

It all comes down to installer competence. many bad reviews of any clutch is due to install error

their customers service blows as well!

[Bakeme521]

Originally Posted by 99three

Does anyone know the weight of the stock FW vs the light weight FW? As I recall a lighter FW=quicker spool up! I'd love to hear what all the "chatter" is about....a sound clip would be a great deciding factor. Are we talking marbles in a coffee can sound?

stock is 34 lbs and i just switched to a 17 lb one. Half the weight is pretty noticeable to me.

Originally Posted by Former_Boosted_IS

The whole LWFW chatter could be eliminated if we could raise the idle to like 900 rpms.

I said that same thing when I installed mine, I can hold the revs up just a tad and it goes away.

[jippii ensio]

Originally Posted by StretchNpoke

Installed lighten fly wheels on many other previous cars including my own. The owners had a case of the placebo effect. I didnt notice crap and i even kept telling myself....it revs quicker!?? fast forward 100k miles later replaced it with an oem wheel and the car felt the same.

To sum up just run the lighten wheel so you can tell yourself its faster.

This.

Paying hundreds for removing 17lbs makes a difference in your wallet, but it does not result in any measurable effect in acceleration. I hear Clutchmasters resurfaces the stock flywheel for $30.

[cstavaru]

Originally Posted by Former_Boosted_IS

The whole LWFW chatter could be eliminated if we could raise the idle to like 900 rpms.

You can, with the INPA software. The car will just consume a bit more fuel in city driving.

[99three]

Originally Posted by Bakeme521

stock is 34 lbs and i just switched to a 17 lb one. Half the weight is pretty noticeable to me.

17 lbs is quite a bit! For everyone else who is skeptical about the lighter flywheel phenomenon consider these facts:

• A LWFW provides the increased response which equals increased acceleration.
• The engine can rev higher, faster and doesn't have to use as much power to do so.
• Transmissions and drive train parts, like a flywheel, suck up a good portion of an engine's power. The more you can do to reduce that, the more power gets to the wheels.
• The less weight the engine has to rotate, the faster that engine will rotate. This translates into an increase in throttle response, which means it will require less pressure on the gas pedal to achieve the same result.

I also like the fact that 17 lbs is being shaved off the car...especially in the front end where it counts!

If we measured the power output of an engine first with light flywheel and then again with the standard part on an engine dyno, no change in power will be seen. At first it appears that the light flywheel has done nothing and was a total waste of cash as some have already suggested. This is not the case. A dyno that shows max power at constant revs does not demonstrate what happens to an engine's power output in real life situations - like acceleration. If an engine is accelerated on a dyno (we are talking about a rate of around 2000rpm a second ) it would show a power output of around 20%-25% less than at the constant rev state.

The reason for this is that when accelerating a vehicle the engine not only has to push the total mass of the car but the internal components of the engine need to be accelerated also. This tends to absorb more power as the extra power is used accelerating the internal mass of the engine components and is why a motor accelerating on a dyno will produce less power than at constant revs. Also it must be remembered that the rate of acceleration on the engine internals is much greater that the rest of the car. This would then suggest that by lightening the flywheel, less power would be required to accelerate it and therefore more power would be available to push the car along.

[A4rings]

Originally Posted by jpsimon

if you can get over the rattle then it's great. I've had the stage 3 clutch+lightweight flywheel for 10's of thousands of miles now and it performs fantastic... you just need to get over the noise (i hold the clutch down at stop lights).

That is bad for the pressure plate.

[A4rings]

Originally Posted by StretchNpoke

Installed lighten fly wheels on many other previous cars including my own. The owners had a case of the placebo effect. I didnt notice crap and i even kept telling myself....it revs quicker!?? fast forward 100k miles later replaced it with an oem wheel and the car felt the same.

To sum up just run the lighten wheel so you can tell yourself its faster.

This is just not true...there was something fishy about your set up or you are the same type of person who can't tell the difference between oem DP's and Cattless DP's.

[A4rings]

Originally Posted by StretchNpoke

Clutch chatter isnt something that you can hear at idle or in motion. Its a combination of increased pressure plate force + kevlar/friction disc material type/puck style/unsprung disc. Its a sticky vibrating grabby sensation as the power train engages. You and the whole car will feel it.

?

[#Tee]

again its on my previous cars and others and not a n54. This is not engine specific, just going off what ive experienced. But you can go ahead and keep telling yourself its faster.

[A4rings]

Originally Posted by jippii ensio

This.

Paying hundreds for removing 17lbs makes a difference in your wallet, but it does not result in any measurable effect in acceleration. I hear Clutchmasters resurfaces the stock flywheel for $30.

http://chicaneculture.com/2010/05/basics-flywheel/

"If you accept that you will accelerate faster with a lighter flywheel, you also have to accept that you will lose speed faster and have to work harder (more frequent input) to maintain your momentum. There isn’t any power increase in the scheme of things, just a change in the rate of rotational momentum and the storage efficiency of this momentum."