Help with new flywheel and clutch for M42 turbo build.

[ccsdo5]

So just looking for some input. I'm currently working on rebuilding my M42 and turbocharging it. I want to try and make 250-300whp but would LOVE to make more power down the road. Clearly the stock clutch and flywheel will never be able to handle it... So would would you guys suggest getting for this? Personally I haven't done a whole lot of research about it but I think there is a way to use a M20 flywheel ... not totally sure lol

Any help would be awesome thanks!

[Dj Buttchug]

Stock dual mass flywheel and clutch will hold 10 psi.

Any more than that and your gonna want to go m20 fly with a good clutch and pressure plate.

Clutchnet.com has good stuff reasonably priced
My set up is as follows
M20 starter
Lightened m20 fly
2nd stage organic clutch and pressure plate
Euro 323 throw out bearing

[bmwman91]

So apparently the 323 TOB is not required. Metric Mechanic sent me a full M20 clutch setup with the lightened flywheel and it has worked fine like that. I too used a 323 TOB on my first 318 when I swapped flywheels, thinking it was required, but it seems that it is not.

Also, according to Metric Mechanic, the M30 flywheel and clutch fit. So there is that if one is pushing crazy boost.

[jntar]

Stock dual mass flywheel and clutch will hold 10 psi.

Any more than that and your gonna want to go m20 fly with a good clutch and pressure plate.

Mine's slipping on 10psi. Gets better after the car has been driving for 20-30minutes, but still slips in 4th on WOT.

[ccsdo5]

Okay thanks for the input guys. I've done a little more research and I think this is what I'm going to be doing.

http://store.bimmerworld.com/jb-racing-aluminum-lightweight-flywheels-p167.aspx

This flywheel

http://store.bimmerworld.com/clutchmasters-performance-clutch-kits-p1293.aspx

With this clutch kit.

http://store.bimmerworld.com/throw-out-bearing-p531.aspx

And this throw out bearing.

...I'm just not sure what stage clutch I want to get. I wanna daily drive the car too so anything too heavy might not be what I'm looking for lol.

[roguetoaster]

You should really consider going the M20 single mass route instead of spending more money on a flywheel that is only marginally (and probably imperceptibly to most of us) lighter. IIRC the M20 FW we had on the Chump Car with a stock M42 was ~13lbs and the stock dual mass was ~21lbs and it was all the improvement we needed. The point is 8lbs is a lot of change in that system, not to mention that a performance clutch kit may weigh less than stock with an altered PP.

As to the clutch there is no reason to go with a clutch above stage two for a DD. Unless of course you like abrupt engagement, which is really awful stop & go traffic.

As to the TOB, it does seem that the updated one will work in an M20 FW/clutch swap and you do not need the 323 unit. Wish I had known that before.

[bmwman91]

I second the M20 flywheel recommendation. If it has been lightened, you don't even need the spacer ring from the M42 flywheel since the flywheel will clear the upper pan. MM sent me a ~11lb M20 flywheel and it is perfectly fine to drive with in traffic. Spins up FAST! Now, the G240 tranny will sound like a coffee can full of rocks when sitting at idle with the clutch pedal up, and when engine braking, but that's the price you pay with a lighter flywheel.

Speaking of transmissions...you are going to shred G240's with 10PSI (assuming ~250bhp?). I'd look into fitting a beefier tranny. According to MM, you can take the G250 tranny/DS/diff from an E36 318ti and fit them in without too much trouble, and it will hold a lot more power while not being heavy as hell like the M20's G260. I have not done the swap myself though, so I can't confirm.

[ccsdo5]

I'll most likely go with an M20 single mass flywheel lol I'm months away from this though I just finished breaking my motor down and now gotta bring it to a machine shop lol.

As far as the transmission goes, I want to fit a better one in but for the mean time I'm gonna just beat on the g240 because what the previous owner told me it was probably on its way out. I think he said second gear was grinding a little. But when it is totally dead then I'll swap to something better

[glucklich21]

323i flywheel-13.6 lbs and getbmwparts.com was able to get it to me for $260 way back when. Run a higher stage Spec M20 clutch and I think you would be golden.

[irish44j]

My fairly extensive try/measure/etc of the M20 FW on M42. Both threads have different conversations, so figured I'd link to them both so you can get the most info.

http://www.r3vlimited.com/board/showthread.php?t=269072&highlight=definitive

http://www.m42club.com/forum/index.php?topic=16724.0

[TobyB]

the M30 flywheel and clutch fit.

I don't see how they could,

t

[MF DOOM]

You should really consider going the M20 single mass route instead of spending more money on a flywheel that is only marginally (and probably imperceptibly to most of us) lighter. IIRC the M20 FW we had on the Chump Car with a stock M42 was ~13lbs and the stock dual mass was ~21lbs and it was all the improvement we needed. The point is 8lbs is a lot of change in that system, not to mention that a performance clutch kit may weigh less than stock with an altered PP.