Dual Mass or Single Mass Flywheel

[EthanolTurbo]

Thanks for sharing your experience with this. I've also looked at this, did you go with their stage 1 clutch then?

I went with the Stage 1 PCS steel flywheel. I waited so long for the order he discounted it to the cheaper aluminum price lol. That being said, NVH and gear lash noise with a single mass on a 420g should be expected but if you're OK with that, the performance boost and driving feel are worth it.

[sdwz_m3]

Well I guess I'll post some thoughts, about to get the car up and running again but I still remember how it was a few months ago.

Really good responsiveness, makes downshifts more fun and definitely adds an extra edge of speed and lightness to the drivetrain. There is quite a lot of idle "chatter" (which from what I've been able to research is a result of gear lash noise when the 420g has a singlemass and also may vary depending on the age and condition of your trans) even with the steel flywheel, so if you hate NVH stick to stock.

I would say stock is REALLY hard to beat for the price and longevity. But if you have a solid build going on and your clutch needs refreshment, going single mass wouldn't be a bad idea. I did this mod because I was already in there, my stock clutch worked fine but I had no idea the remaining lifespan, and because my build pretty much has everything else so it would be weird to hamstring it with a stock clutch and dual mass. I also never want to change the clutch again, and from what I can tell this clutch should last 200k+ miles.

At the end of the day, there's way more important, meaningful upgrades that should take priority over this one but if you are already doing a build and need to do the clutch job and/or want maximum performance, this is worth the extra $700-1000 over OEM.

Thanks for sharing your experience with this. I've also looked at this, did you go with their stage 1 clutch then?

[EthanolTurbo]

Ordered a Rogue Engineering PCS clutch kit with steel flywheel. I'll post some thoughts in this thread after I install it and break it in. Hoping it ends up scratching my OEM+ itch.

Well I guess I'll post some thoughts, about to get the car up and running again but I still remember how it was a few months ago.

Really good responsiveness, makes downshifts more fun and definitely adds an extra edge of speed and lightness to the drivetrain. There is quite a lot of idle "chatter" (which from what I've been able to research is a result of gear lash noise when the 420g has a singlemass and also may vary depending on the age and condition of your trans) even with the steel flywheel, so if you hate NVH stick to stock.

I would say stock is REALLY hard to beat for the price and longevity. But if you have a solid build going on and your clutch needs refreshment, going single mass wouldn't be a bad idea. I did this mod because I was already in there, my stock clutch worked fine but I had no idea the remaining lifespan, and because my build pretty much has everything else so it would be weird to hamstring it with a stock clutch and dual mass. I also never want to change the clutch again, and from what I can tell this clutch should last 200k+ miles.

At the end of the day, there's way more important, meaningful upgrades that should take priority over this one but if you are already doing a build and need to do the clutch job and/or want maximum performance, this is worth the extra $700-1000 over OEM.

[chapmans]

I have a JB Racing flywheel and a RTD shifter and it is really loud. The idle chatter is fine but the one that really annoys is a nasty resonance around 5k rpm.

[EthanolTurbo]

Ordered a Rogue Engineering PCS clutch kit with steel flywheel. I'll post some thoughts in this thread after I install it and break it in. Hoping it ends up scratching my OEM+ itch.

[BTB]

I had a BimmerWorld 'street' kit - Clutch Masters kevlar sprung disk w/ JB Racing flywheel (link). As much fun as the lower rotating mass was (and it was very drivable, smooth, just loud) I will not be going back. Stock is smooth, quiet, and you hardly notice any difference in willingness to rev free.

Just another data point/opinion in favor of OE.

[digger]

Digger,

It should have been said It helps a lot. No one is
mentioning it will fix the problem. Straight MT90 is
is very thick compared to ATF family oils. MT90 takes
a lot of time to heat up in order to chatter and
still then never as loud as ATF family thin oils.

But everything comes with a price. In cold
weather it won't shift properly till the oil sees some
heat.

Those who don't like chatter should go with Dual
Mass and call it a day.

Regards,
Anri

It will still make noise when it’s hot. When hot the difference in viscosity between grades gets smaller and smaller

[sapote]

I have both G420 and Citroen Sm boxes in the garage. Will check and compare the gears backlash.
Both should have zero input shaft axial and radial plays.

[9kracing]

I'm running the full face ACT clutch and flywheel package and I love it.

-In gear acceleration for 1st/2nd quicker. The car really comes alive above 3k and pulls hard until redline.
-The exhaust sounds a tiny bit different as it moves through the range quicker.
- Downshifting, the revs come up a little faster, but not a super dramatic change.
-The clutch pedal is firmer, and I do like the increased feel.
-The engagement is not choppy or harsh, and feels similar to the stock clutch.


There was a rattle in neutral, but I've bumped my idle to 950 and it sounds like stock inside the car now.

Another vote for ACT here. I'm running the clutch and flywheel and it's pretty close to stock feeling for how much torque it holds.

[Anri]

Oil won’t fix the problem.

Digger,

It should have been said It helps a lot. No one is
mentioning it will fix the problem. Straight MT90 is
is very thick compared to ATF family oils. MT90 takes
a lot of time to heat up in order to chatter and
still then never as loud as ATF family thin oils.

But everything comes with a price. In cold
weather it won't shift properly till the oil sees some
heat.

Those who don't like chatter should go with Dual
Mass and call it a day.

Regards,
Anri

[digger]

Oil won’t fix the problem. I lightened e28 m5 smfw will still rattle a bit on the older getrags but still bearable and thicker oil has a minimal effect

[Anri]

But why no tranny gear rattling?

Not sure why are you comparing Transaxle with G420 Getrag ?

Gear mesh design, teeth shape, gear lash, input shaft play all
contribute to chatter.

The Input shaft on every BMW is very lose by its design, next time you
do clutch job on your car while the gear box is out grab the input
shaft and move it up and down...and note how much play you will
find.

Go do the same test on Mercedes NSG370 the input shaft moves
much less.. and no chatter at all.

Transmission Chatter is related to single cause, gear lash settings,
also input shaft lash/play.

[Anri]

Yes, as you said about the guide sleeve and so I believe the guide sleeve for the throw out bearing. I just can't see how do the 4 springs around this location can dampen the input shaft and the gears inside from rattling.

Sapote,

No no what you tougth is called Input-Shaft-Guide-Sleeve,
the Sleeve goes over the Input shaft and its bolted to the
bell housing.

I am talking about Internal guide sleeve, it is located inside
of the transmission behind the input shaft gear

Regards,
Anri

[sapote]

My Citroen SM with the Maserati 90* V6 odd-fire engine with the ignition timing having different period, and so it runs so uneven at idle like a Harley Davidson. But why no tranny gear rattling? Heavy gear oil I think. 90* V8 is smooth because the ignition firing is even, not the V6.

[sapote]

Inside the gear box in the guide sleeve internally BMW installed
if memory serve me well 4 small springs.

TOB means (Throw-out-Bearing)?

Yes, as you said about the guide sleeve and so I believe the guide sleeve for the throw out bearing. I just can't see how do the 4 springs around this location can dampen the input shaft and the gears inside from rattling.