Lightweight Flywheel conversion

[lambertius]

So what sort of weight do you reckon is a good balance between street use and getting a sportier drive from the car - something a bit more suitable (or rather enjoyable since the stock unit can stand up to it) for the occasional track day?

I've seen the UUC one at around 3.8kg (~8 pounds) which sound pretty much race only to me, but then I'm not sure what else to pick from. Getting some wrecked parts can be quite difficult here in Australia, so finding a decent lightweight kit that I can just buy would make my life a lot easier!

Is there anything anyone can recommend?

[wazzu70]

I typically use something between 13-15 pounds (6-7kg) as the lightest weight. The 8lb (3.5kg) units are too light.

Your best option is an M20 flywheel or a M42 non-A/C flywheel. Either one will probably require shipping for you though

[Warsteiner]

I would say no less than 11-12lbs. For reference, the E30M3 LWF is 12lbs which was made specifically for the EvoII and other iterations.

It does make a huge difference from the stock unit in terms of spooling up. But you also have to watch your shifting because your revs drop much much quicker now.

Cheers,
~Ralph

[lambertius]

So if I were to get something like this http://www.ebay.com.au/itm/BMW-E30-M20-Manual-flywheel/201106527634?_trksid=p2045573.c100033.m2042&_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D20131017132637%26meid%3D7581593044856384339%26pid%3D100033%26prg%3D20131017132637%26rk%3D2%26rkt%3D4%26sd%3D281231408861

and this

http://www.ebay.com.au/itm/CLUTCH-KIT-BMW-E30-E36-316i-318i-318ti-M40-M42-M43-M44-SOLID-FLYWHEEL-/360940079850?pt=AU_Car_Parts_Accessories&hash=item5409b48aea&_uhb=1

That would be a good solution?

Do I need to get a different type of flywheel bolt, and the ring gear should be fine for the starter motor on the M44?

[bmwman91]

I'm running a 11.5lb MM M20 flywheel in mine. Perfectly pleasant to drive, no chatter, shifts smooth. The M20 PP weighs 5lbs more than the M42 one, so really the entire assembly is 13lbs lighter rather than 18lbs.

Rattle. Yup. Car sounds like a coffee can full of rocks when idling with the clutch pedal up. I also get some fairly loud rattle/grind when engine braking in 5th gear under 40MPH and sometimes in 3rd gear if the road is smooth (quiet). I cared at first, but at this point I just ignore it. Maybe the car DOES sound like an old beater, but since I live in an area where people have way more money than brains, I'd have to drive a new $80k car to "get any respect" anyway. Since impressing strangers isn't exactly on my list of concerns it's all good. Now, if you are a little more concerned with being seen in a car that sounds like it is falling apart (and it's perfectly fair to want to avoid that), then maybe stick with the stock flywheel. Even when I ran a stock 19lb M20 flywheel, I had some tranny rattle. Not nearly as loud as it is now, but it was there.

I am running RedLine MT90. It is a little quieter than RedLine MTL. Both are quiet when the tranny is cold, but once it heats up and thins out the oil it gets noisy. Wazzu's suggestion about the gear oil mix sounds intriguing and I'll probably try that next time I am due for a fluid flush.

I avoid sitting with the clutch pedal pressed at idle. Certainly on a stock engine it is not a hot plan because that half-shell thrust bearing is notorious for pooping out, and idle is when oil pressure is lowest. I have a full 360 degree thrust bearing pair, but even still I don't want to put any undue stress on it. On a related note, NEVER start the car with the clutch pressed in. Full clutch force on half a thrust bearing with zero oil pressure is going to lead to massive crank end play eventually, guaranteed.

[nickmpower]

I have an 8.5lb flywheel, you have to try pretty hard to hear any chatter/rattle at idle or otherwise. I think I bumped up the idle speed

[lambertius]

I have an 8.5lb flywheel, you have to try pretty hard to hear any chatter/rattle at idle or otherwise. I think I bumped up the idle speed

Whats it like driving with such a light flywheel, especially on the road?

[Slowered318]

I'm running a 11.5lb MM M20 flywheel in mine. Perfectly pleasant to drive, no chatter, shifts smooth. The M20 PP weighs 5lbs more than the M42 one, so really the entire assembly is 13lbs lighter rather than 18lbs.

Rattle. Yup. Car sounds like a coffee can full of rocks when idling with the clutch pedal up. I also get some fairly loud rattle/grind when engine braking in 5th gear under 40MPH and sometimes in 3rd gear if the road is smooth (quiet). I cared at first, but at this point I just ignore it. Maybe the car DOES sound like an old beater, but since I live in an area where people have way more money than brains, I'd have to drive a new $80k car to "get any respect" anyway. Since impressing strangers isn't exactly on my list of concerns it's all good. Now, if you are a little more concerned with being seen in a car that sounds like it is falling apart (and it's perfectly fair to want to avoid that), then maybe stick with the stock flywheel. Even when I ran a stock 19lb M20 flywheel, I had some tranny rattle. Not nearly as loud as it is now, but it was there.

I am running RedLine MT90. It is a little quieter than RedLine MTL. Both are quiet when the tranny is cold, but once it heats up and thins out the oil it gets noisy. Wazzu's suggestion about the gear oil mix sounds intriguing and I'll probably try that next time I am due for a fluid flush.

I avoid sitting with the clutch pedal pressed at idle. Certainly on a stock engine it is not a hot plan because that half-shell thrust bearing is notorious for pooping out, and idle is when oil pressure is lowest. I have a full 360 degree thrust bearing pair, but even still I don't want to put any undue stress on it. On a related note, NEVER start the car with the clutch pressed in. Full clutch force on half a thrust bearing with zero oil pressure is going to lead to massive crank end play eventually, guaranteed.

Changed my fluid from RedLine D4 ATF to Redline MTL last week, seems to have slightly reduced gear noise. I may try MT90 next time if I find the MTL doesn't get too thick in the cooler season.

I was never aware of the start up issue you described. I have always started the car in neutral with the clutch fully depressed (easier on my starter motor) then I leave in in neutral during warm up to get the gear oil flowing. Is this bad for my drivetrain in some way? I drive quite a bit in heavy traffic at low RPM (usually second gear) working the clutch quite a bit, never had a major clutch failure due to this.

[bmwman91]

I wouldn't worry about the tranny. Just the crank & thrust bearing. The starter might sound like it is working a little harder with the clutch pedal up, but it isn't hurting it. Even if it did, you can get a used starter for like $40...can't say the same about a bottom-end rebuild!

[Slowered318]

I wouldn't worry about the tranny. Just the crank & thrust bearing. The starter might sound like it is working a little harder with the clutch pedal up, but it isn't hurting it. Even if it did, you can get a used starter for like $40...can't say the same about a bottom-end rebuild!

Noted, I'll give it try from now on.

[Slowered318]

Update:

Been running a MM 11 lb single mass flywheel with 228mm clutch since last fall. Very pleased with the Metric Mechanic product compared to the Valeo, experiencing much less noise and vibration.