m20 singlemass flywheel machining

[F34R]

Mine rattles and it was a Metric Mechanic one...

My understanding is it's from the transmission? Mine only rattles when I have the clutch in (as in, the tranny is turning in neutral)

How light is it?

[kendogg]

Idiot....I guess because "techno 550" (or should I say "notech 550") said it over on bimmerforums it must be correct

Actually, he's an automotive engineer, owner of TRM (The Racers Market), and has extensive engineering experience in the pro racing community. I think you're the moron here buddy. Perhaps you should stop and listen, and perhaps take some physics courses before spouting about whats correct and what isn't (since you're completely NOT correct)?

[kendogg]

It is from being too light, or done wrong. Also you got to think about all of the given things in play: pressure plate, torque from engine. Everything could make an issue if done wrong.

Could snap and shatter if too much is removed. I have heard of 11lbs being run with a 6 puck, no issues. But I WOULD not do it, I felt happy with 13lbs.

The rattle spoken of comes from the gearbox. Has nothing to do with the clutch.

[F34R]

The rattle spoken of comes from the gearbox. Has nothing to do with the clutch.

I have never had a light fly yet or ever researched much on where the rattle comes from. All I know is it helps out tons with reving.

[kendogg]

I have never had a light fly yet or ever researched much on where the rattle comes from. All I know is it helps out tons with reving.

With free-revving (unloaded, rev-matching, etc.), yes. It doesn't make the car accelerate any faster though. If you like it - cool, get one, just don't expect to feel any power difference, because you won't. I suggest attempting to drive a car with one first though.

[erik325i]

LTW flywheel is ricer crap no matter what you guys say. The intertia of your car means the .00001% of weight you shave basically does dick...but think what you want, I will still think you are a clown with a car that rattles while you tell yourself that you are a racer.

BTW: Cars built for racing (ya know, ones that take a trailer to the track) are a whole different ballgame. I only laugh at the clowns rattling at a stoplight.

You do know not all light weight flywheels rattle, right? As long as you don't get too carried away and make it too light, it shouldn't rattle.

I do agree that a car that sounds like it has marbles in the transmission has no place on the street.
I'm all for having a light flywheel though (within reason). It makes driving and rev matching much more enjoyable.

[F34R]

You do know not all light weight flywheels rattle, right? As long as you don't get too carried away and make it too light, it shouldn't rattle.

I do agree that a car that sounds like it has marbles in the transmission has no place on the street.
I'm all for having a light flywheel though (within reason). It makes driving and rev matching much more enjoyable.

That is why I went safe with 13lbs

With free-revving (unloaded, rev-matching, etc.), yes. It doesn't make the car accelerate any faster though. If you like it - cool, get one, just don't expect to feel any power difference, because you won't. I suggest attempting to drive a car with one first though.

I rode in a friends that had it done, he loves it and I love matching revs.

[rThor432]

There sure are a lot of opinions in this thread..

I'll share a fact:

I experienced no increase in NVH when I switched from the stock 27 lb. (or however heavy..) dual mass flywheel to an 8 lb. JB flywheel in my 318is-- with a stock unsprung clutch disc. There was no extra gearbox noise or anything.

And an opinion:

The flywheel swap made the car drive like it should have from the factory.. The heavy flywheel is quite a burden on that poor little powerless 4-pot.

[ZekeTheSneak]

yes i plan to go with a 13lb flywheel, it does help with acceleration but you loose momentum in top end but i want the fun r3v matching and quick shifting. thank you all for the input. I will be installing a light weight flywheel and i will let you all know how it goes :)

[ZekeTheSneak]

oh and most rattles come from crazy clutch setups such as unsprung and heavy duty clutch packs.

[Jand3rson]

oh and most rattles come from crazy clutch setups such as unsprung and heavy duty clutch packs.

This. I will be using a stock M20 Sachs clutch kit. Lightweight flywheels on the street don't faze me. It's the retards running 6-puck unsprung racing clutches on the street that make me giggle.

[F34R]

It's the retards running 6-puck unsprung racing clutches on the street that make me giggle.

Like that one kid with the SHIT turbo 5er a week or so back. Spent 600 or so on something that he will NEVER be able to match in HP/tq.

[ZekeTheSneak]

Haha this goofy drifter kid at my highschool had an unsprung clutch and he always had to Honda r3v to move anywhere, his 240 did have an sr though

[Aptyp]

I like 12-13lbs flywheel and stage 3 sprung clutches... makes m20 a whole lot smoother. It's kind of pointless on the E, because you're not reving too far anyway.



Also, people arguing that it's not making car quicker... It helps power delivery to take parasitic weight off. Taking weight off the flywheel is the same as getting lighter rods or aluminum pulleys, or taking fan clutch off. Little improvements like that do make the car quicker, just by smoothing out torque and hp curves. It's a lot more enjoyable to smoothly rev up an engine in a 20 year old car.

Another machining upgrade is to take weight of the front harmonic balancer.

[Drew325is]

Here's another link with mathemagics 'n' stuff to explain the benefits of light flywheels:

http://www.pumaracing.co.uk/FLYWHEEL.htm