What lightweight flywheel do you guys reccomend for my 540? I can't find on at UUC (unless you upgrade the clutch too....$2500+) so I'm having to look around. I found one here: http://jbracing.com/flywheel-bmw5.php#e39models that someone on this forum mentioned, but I'm not sure if I trust them.

Suggestions?

-George

PS: SPEC also makes one at Evosport. Are they reputable?

The thing to point out about the UUC flywheel is that is that it is a conversion... you use the much bigger clutch from the V12-powered 850CSi. This gives you more torque capacity, longer life, better clutch feel (no SAC mechanism like the OE 540i setup), and a sprung-hub center for the clutch to reduce or even eliminate flywheel/gearbox rattle. For details on what causes gearbox rattle, please see:
http://www.uucmotorwerks.com/flywheel/gear_rattle.htm

The problem with lightweight flywheels for the E39 V8 cars (540i and M5) is that they end up being too light... this results in difficulty achieving a smooth, slow take-off in 1st gear, excessive gearbox rattle, and negatively impacts how the car feels.

The UUC setup is a modest 13lb overall weight reduction - enough to give you a nice performance boost and quicker throttle response, but not so much as to create the negative effects listed above. For details on this product, please see:
http://www.uucmotorwerks.com/flywheel/V8/index.htm

If you visit m5board.com, you'll see plenty of complaints about standard-clutch lightweight flywheels. As the chassis and transmission are the same between the M5 and 540i, their comments apply directly to the 540i.

Damn....that's annoying....so you're saying I have to spend $3000 to get a good clutch and flywheel? That seems a little steep.....

-G

Damn....that's annoying....so you're saying I have to spend $3000 to get a good clutch and flywheel? That seems a little steep.....

-G

Not "good" - simply the "BEST".

This is the same setup that Discovery Automotive uses in all their M5 and Z8 supercharger packages.

... and it's not $3000, it's $2750.

- Rob

I have the JB Racing Flywheel... it is a nice piece... I have around 30k miles on it so far without a problem. Car revs nicely but there is some chatter at idle with the clutch disengaged and the air conditioner on.

I have the JB Racing Flywheel... it is a nice piece... I have around 30k miles on it so far without a problem. Car revs nicely but there is some chatter at idle with the clutch disengaged and the air conditioner on.

The E39 idles at a lower rpm than your E34, making the rattle even worse.

- Rob

The E39 idles at a lower rpm than your E34, making the rattle even worse.

- Rob

interesting... i didn't know that... where do the m62's idle?

My car idles around 500 rpm, maybe even a little lower. This post has some great info. for when I have to do a clutch (probably next year).

There is some helpful info. However, $2700 is just too much. I'm probably going to go with the SPEC lightweight flywheel for the time being and then the SPEC Stage 2 clutch eventually. SPEC makes really nice stuff (even if their customer service sucks) and that's a whole lot cheaper than the UUC.

-George

There is some helpful info. However, $2700 is just too much. I'm probably going to go with the SPEC lightweight flywheel for the time being and then the SPEC Stage 2 clutch eventually. SPEC makes really nice stuff (even if their customer service sucks) and that's a whole lot cheaper than the UUC.

-George

Have fun replacing the Stage2 kevlar when it burns out after your first stoplight drag race. Kevlar does not belong in a street car, particularly a heavy 5-series.

- Rob

Have fun replacing the Stage2 kevlar when it burns out after your first stoplight drag race. Kevlar does not belong in a street car, particularly a heavy 5-series.

- Rob
:)

Point taken.

-G