Stories, how-to, and reviews from my personal tuner shop... my garage.
My collection of media including photos, audio, and video.
Specs, history, pros/cons, and stories about my own 330i.
BMW places on the Internet that I find useful.
UUC LIGHTWEIGHT FLYWHEEL
A lightweight flywheel reduces rotational driveline mass. Less rotational driveline mass means more torque
gets delivered to your wheels. The UUC Lightweight flywheel weighs in at 13.4 pounds. The stock LuK dual-mass
flywheel is about 24 pounds. For each pound of rotational mass you remove from your drivetrain, it is the same as
removing about (7)
seven times that in vehicle weight. So, for example, the UUC lightweight flywheel will remove about 10 pounds of rotational mass. My car will perform like it is about 70 pounds lighter in weight.
What this means is better acceleration and quicker engine response. The downsides to a lighter flywheel are possible
audible idle chatter (where the pulses of the ignition cycle are no longer absorbed by a heavy flywheel and can be
heard in the transmission at idle) and it takes some time getting used to driving with one. A lighter flywheel will
make the engine easier to stall when starting from a stop and your shifts will need to be faster as the RPMs will
drop much faster when you push the clutch in and let off the gas.
1 - UUC Lightweight Flywheel
(UUC MOTORWERKS $499 part #LFWLE46)
This is simply *not* a DIY kind of job. My dealer owed me a new clutch based on an active TSB (Technical Service
Bulletin), and I got it installed at that time.
I looked into doing this modification myself, but it involves removing the driveline, exhaust, and transmission. And,
to get to a few of the transmission bell housing bolts, you have to unbolt the engine and rock it back on the mounts.
This is something I do not have the equipment to support, so I was lucky enough to time this install with my clutch replacement.
IMPORTANT NOTE: If you have a 323/325, you will need to use the clutch and throwout bearing from a 328/330 with
this flywheel. The 323/325 and 328/330 have different sized clutch plates in them. It is also recommended to pick up a
new set of (8) eight flywheel bolts. These are shear bolts and the old ones should not be reused.
PHOTOS Courtesy of UUC MOTORWERKS
Talk about impressive! The engine feels like it has been set free. It revs so easily and is much more responsive. No more
hesitation in the acclerator pedal. This thing just wants to get up and haul ass!
Acceleration feels much improved especially in the early gears, but the difference can be felt in every gear. The RPM
redline is acheived much faster with seemingly nothing standing in the engine's way.
Shifting took a few miles to perfect, but it is absolutely incredible now. I used to out-shift the engine/tranny before;
the RPMs never dropped enough to put me into my next torque "sweet spot". Now, my shifting speed is matched by the change in
engine speed almost as if by design. Even my short shift kit seems smoother.
Idle chatter is barely noticable inside the car. If you even have the A/C fan on, you won't notice it. If you use your
radio every day (like me), you will forget about any chatter in no time. Outside the car, the chatter is more noticable. I would
say it about doubles the volume of your engine. I only got chatter when in neutral and my foot off the clutch.
Since 99% of my driving involves NOT being in neutral, the performance gain far outweighs the noise issue.
SOON TO COME: I will be doing a short video of the tach before and after to show the difference in engine response and the
idle chatter inside and out.