LWFW in 1.9 Z3

[DanZ3]

Anyone have experience with a LWFW in a 1.9? Looking to get as much out of the 1.9 without FI.

[eluther3z3]

Lwfw?

[Z3DarkS1de]

Light Weight Fly Wheel

[z3540i]

I read somewhere about m3 flywheels working and being lighter than the dual mass.....several threads about it out there. I would look other places to mod as in maybe a diff swap to a 3.73.

you don't gain any horsepower with a lightweight flywheel you simply reduce the amount of drivetrain loss... Doesn't seem to be worth the money for the small gain

[setho1993]

Would it be possible to just lighten and balance the stock flywheel?

[z3540i]

I don't think so...the stock is a dual mass flywheel and i dont think they can be lightened.

[Joemamaman]

it might not seem like much on paper, but a ltwfw makes a noticeable difference in the driving experience... the engine revs up much quicker, and feels peppier. It also doesnt hang in the high rpm's when you let off the gas. Well worth the money. Get rid of the rotational mass!

I'm running Fidanza ltwfw, w/ Sachs M5 sprung disk, and Sachs '96 M3 pressure plate. Its a perfect combo/upgrade for the 1.9's. No clutch chatter. stock feel, but definitely better. It should hold fine for whatever we're up to.

Not to mention you can't resurface a DMFW (stock 1.9) You can only replace, so turns out you'll be spending almost the same amount as the lighter, uprated setup. As for long term, if you ever need to resurface a fidanza light FW, a new friction surface is $45-50, and just swaps right on.

[DanZ3]

The Fidanza, M5 disk, M3 clutch seems to be most common for the 1.9. No gear chatter at all? I was looking for a complete kit. Is there a lightened steel FW available that's between dual mass and aluminum?

[zmRoadster]

The issue is that just for swapping to a LWFW, everytime I see recommendations on getting a M3 part here, the clutch from there, replace the clutch slave cylinder from this BMW model and the LWFW from that another

Why not just buy the correct parts for the car (Z3 1.9)?
Im going to replace mine with a JB Racing LWFW (alum 9 lbs) and a stage 2 SPEC clutch (mine is DASC Supercharged). Both parts are OEM like and don't need any modification or changing any other parts (the JB Racing LWFW works with any stock clutch)

[Joemamaman]

Correct, no clutch chatter at all.
Come to think of it, I did swap in an M3 clutch slave too. I just figured while I was down there, and was going to install a SS braided clutch line anyway... why not. It was a no brainer.

Clutch drives and feels perfect. No heavy pedal, smooth and quiet. Not what I'd use for drag strip, but this isnt a drag racer. Awsome for street, and modest track days.


As for the M5/M3 setup.. it's not modifying anything. It's swapping parts made for oem. Just oe parts that bolt on perfectly. I think we're lucky all these uprated oem parts fit~

The reason to consider the M3/M5 setup is this:
-More options on aftermarket ltwfw for M3 than one for the 1.9
-M3 ltwfw is cheaper than lwtfw for 1.9 (at least when I was shopping)
-The clutch disk and diaphram are oe parts (Sachs is a oem manufacturer for BMW clutches...good quality at good prices)
-Many choices for M3, M5 clutch disks... (but oe M5 disk is fine for 1.9)
-The oem M3/M5 setup is slightly larger in diameter, and has a higher power capability than the smaller stock sized 1.9 clutch disk. You dont need aggressive compounds/disks or heavy pressure plates.

**by piecing the mixed ltwfw/clutch setup for the 1.9, its cheaper than buying a pre-arranged clutch kit.


The Setup w/ the JB flywheel for the 1.9 is nice, but it costs more than an M3 LWFW (when I was shopping), and the only clutch options are aftermarket. btw, I will never use a SPEC clutch in any of my cars again. Same thing with CrutchMasters clutch kits. But that's just from my own experience... so the choice is yours.

[zmRoadster]

The JB racing LWFW works with the stock 1.9 OEM clutch options, you don't need any aftermarket options

But as any change from dual-mass flywheel to a single lightweight flywheel (in street applications), you NEED to replace with a sprung clutch, to compensate for the removing of dampening in the driveline at the clutch engagement

I wonder if the fidanza flywheel, M5 clutch, M3 pressure plate, M3 slave cylinder is cheaper overall than the 600 bucks JB flywheel

[DanZ3]

The more research I do on LTFW for my application, DD + occasional club autocross the more I think it may not be the right thing to do.

[maxmoto]

The more research I do on LTFW for my application, DD + occasional club autocross the more I think it may not be the right thing to do.

LOL!

I read somewhere about m3 flywheels working and being lighter than the dual mass.....several threads about it out there. I would look other places to mod as in maybe a diff swap to a 3.73.

you don't gain any horsepower with a lightweight flywheel you simply reduce the amount of drivetrain loss... Doesn't seem to be worth the money for the small gain

maybe there's your answer, what's the original diff on a 1.9?

[BenFenner]

Dan, you've been lead down the wrong path. A light flywheel is a pleasure to deal with. There is absolutely no reason to avoid it, even on a lazy daily driver. There really are no down sides, and if you have even half a mind toward performance, they reward in spades.

A light flywheel is near the top of my enjoyment/dollar metric (assuming labor is "free").

[Joemamaman]

Totally agreed w/ Benfenner~

It's great because there's no tuning involved.. just install, and enjoy... and you WILL notice the difference.


For price.. I got my Fidanza M3 ltwfw for $400.. give or take a few bucks... from HPfreaks a couple yrs ago. I think I spent aaround $300 +/- $50 on the disk and diaphram setup.. Overall, less than $800, and its a helluva better setup than a stock replacement.

It's correct to use a sprung hub clutch disk when you swap to a ltwfw, but what oe application has a sprung disk for a 1.9? I never found one. Only aftermarket.

Meanwhile, you can use Sachs oe sprung disk for an M5. Good oem quality.

Overall, it's up to you.. but imho, it's a no brainer to swap to M3/M5 clutch setup when replacing a 1.9 clutch. Driveability is excellent.


Btw, if you want to swap final ratio, consider if you drive hwy miles... because you're gonna be reving higher just to cruise. It sucks we only have 5 gears, and they run out quick w/ a final ratio swap.
I'm ok with it because I drive almost all surface streets... accelerating all the time from block to block, so the new ratio is fun. meanwhile, when I get on the fwy... it sucks. Need a 6th gear~
(I went from stock 3.46 to a 3.64 LSD)

[maxmoto]

There's another post here on BF:
http://forums.bimmerforums.com/forum...d.php?t=692230
It seems to be quite a debate on which setup to use, and some interesting discussion between UUC and Bimmerworld...

[Joemamaman]

yea.. its up to you to do what makes you feel comfortable.

All I can say is I'm happy with my setup.

[maxmoto]

I'm running Fidanza ltwfw, w/ Sachs M5 sprung disk, and Sachs '96 M3 pressure plate. Its a perfect combo/upgrade for the 1.9's. No clutch chatter. stock feel, but definitely better. It should hold fine for whatever we're up to.

If you do decide to change... my recommendation is:
-'96 E36 M3 lightweight flywheel (any decent aftermarket)
-'96 E36 M3 Sachs pressure plate
-M5 sprung clutch disk (I forgot what year... you can search it though).

All the rest can be oem replacement (doesnt have to be genuine BMW)
I also changed:
-plastic pivot pin (a metal one is available too)
-Throw out bearing
-All small rubber bushings in the shifter linkage (they all need to be removed anyway)
-Delrin bushing in front end of shifter linkage
-E36 M3 Slave (I just did it. Stock on should be ok)
-Stainless braided clutch line

Joe can you help me out here?
Do you have the parts numbers to make the perfect combo?
I need to change my clutch and was thinking on going the same way you did. Unfortunately I have no mechanical skills and my knowledge in this is very poor, besides I live far away from US so I have to import all parts.

It would be of great help if you could point th PN or where to buy all parts.

Thanks!

[Joemamaman]

Hi, It's been a while now, so I'll try to see what notes I have.

Fidanza: Lightweight flywheel for '97 E36 M3
Sachs Pressure plate: '97 E36 M3 (Part number: Sachs 3082 281 031) ($153 at RockAuto.com)
Sachs clutch disc: E34 M5 (Part number: Sachs 1861 931 034) ($104 on Amazon, Prime= 2 day free ship)

I also replaced:
Throw out bearing
Pilot bearing
Throw-out-arm
Throw out arm pivot pin (plastic one)

Additional work I did (not always necessary, but I chose to do)
-New main seal (I had 106k miles on it... why not.)
-new clutch slave (E36 M3)
-new clutch master cyl (Z3 1.9 <-- in hindsight I should have just used M3 Master too)
-new shifter linkage refresh (all bushings associated with shift linkage + delrin pieces too)

****IIRC, with this setup, the sprung, M5 clutch disk installs with sprung hub facing toward the Engine (into the flywheel)


Overall, I did this work on the driveway w/ the car on jackstands. A transmission jack/trolley was key to making it effortless.
Just a lot of nuts and bolts, but no particular step was notably difficult.
Love wrenching on Bimmers... if there's something hard to do, you're either doing it wrong, or using the wrong tools...


Hope this helps~

[maxmoto]

Hi, It's been a while now, so I'll try to see what notes I have.

Fidanza: Lightweight flywheel for '97 E36 M3
Sachs Pressure plate: '97 E36 M3 (Part number: Sachs 3082 281 031) ($153 at RockAuto.com)
Sachs clutch disc: E34 M5 (Part number: Sachs 1861 931 034) ($104 on Amazon, Prime= 2 day free ship)


****IIRC, with this setup, the sprung, M5 clutch disk installs with sprung hub facing toward the Engine (into the flywheel)

Hope this helps~

My new LWFW setup is being installed, can anyone please explain the correct position of the disk???

[Joemamaman]

My new LWFW setup is being installed, can anyone please explain the correct position of the disk???

Wow... its been some years now. I'm sure Maxmoto got it figured out... but from what I recall, the M5 disk has to be installed reversed (flywheel side vs pressure plate side) compared to what's marked on it.
It'll be obvious because of the clearance required with the pressure plate and the area that's milled out on the lighter billet flywheel.
Anyway, its late info, but just in case someone else comes across this thread years later...
:-)