What are the effects of a LTW Flywheel?

[Keanan]

I know Lightweight Flywheels will help the engine rev easier but how do they effect a M52/S52? If stock flywheels are 20 some odd pounds what are 18, 12 or 8 pound flywheels like? Can a lightweight flywheel get to light? What are you guys running and how does it effect your engine?

- Keanan

[dpgrand]

go to www.uucmotorwerks.com, go to their flywheel section, and read.

[rThor432]

Acceleration feels more smooth (and quicker), there is less resistance to revving (duh), and some cars have a rattle 'issue' at idle.

Ive got an 8.5 lb. flywheel in my 318is and I switch off driving that one and a standard 318is we keep at work regularly. So 8.5 lb. vs. 28 lb. That is the basis for my comparison. Mine does not chatter or rattle.

I have a 12.5 lb. flywheel for my S52, but I havent installed it yet so I cant give any input based on that.

Oh, and like the last guy said ^^ the UUC article is a helpful (and quick) read.

[Keanan]

go to www.uucmotorwerks.com, go to their flywheel section, and read.

I read all of the stuff on flywheels before hand. What I am trying to figure out is: How does a lightweight flywheel effect an M52?
Does an M50 seem to prefer a 12 lb flywheel over a 16 lb flywheel? Does it idle differently, With a Lightweight Flywheel is there a loss of torque or launching ability compared to stock flywheel? If I can put a M20 flywheel on an M50, then can I put an 8 lb M20 flywheel on an M50? Is that to light?
If you have a lightweight flywheel on your M50/S50 can you tell me how much it weighs and how it has effected things?

[hoveringuy]

I have a 13lb M20 flywheel.

Revs gloriously, great for snappy downshifts.

My wife tends to stall it more easily.

Only downside is the clanky rattling sound from the gearbox when it gets warm.

[mikeedler]

I have the evo III wheel in my S14 and it doesnt seem to really rev up any different, but when you take your foot off the throttle at 100mph, it sure does slow down alot faster.

[bmws50b30]

only downside to LTW flywheel is if you don't have th eproper chip it will stall if you don't keep the revs up. AS you slow down the revs drops too low that the car stalls. i have a jb racing flywheel

[bwh13]

Take off is a little harder to do smoothly with my 8.5lb FW with S52. I do have it chipped so it's no big deal but it does take a bit of touch to do it without revving the engine too much. Other than that I can't see any downside, other than the idle rattle in nuetral with the clutch out.

[416stroker]

my m50 revs really good my m20 flywheel was cut down just under 8lbs. It's got a pretty good rattle to it at idle . Has a small hesitation off idle other than that of drives great.

[der affe]

slightly OT, but, is the rattle a M/S-50/52 problem or is it in the M-20's too?

[etxxz]

you guys must suck at "stick" i have ltw fly and i can take off in 3rd gear keeping rpm's under 1200. i also have short gearing (3.25 w/ ZF) To be honest, my comparison is my e30 and a stock e36M3. they feel the same, the e36 actually felt faster which lead me to believe my s52 is tired or the main O2 sensors are garbage...neways. there ya go.

also, is good to know that lighter may not be better. You have to consider the moment of inertia of the flywheels. The ebay fly claims 16lbs, when i saw it, it was a solid chunk of chromoly steel so its weight is mostly along the outer diameter making it not so light. There are better flywheels out there.

o yeah, my shit rattles somehow idk why. i keep thinking is the TO bearing..

[pedal2metal]

Take off is a little harder to do smoothly with my 8.5lb FW with S52. I do have it chipped so it's no big deal but it does take a bit of touch to do it without revving the engine too much. Other than that I can't see any downside, other than the idle rattle in nuetral with the clutch out.

+1, if you use, say a JB Racing M20 8lb flywheel, the idle will have to be increased. I think mine is @850-900rpm. The real advantage with a lightweight flywheel comes when you match revs during downshifts.(the engine will rev a lot faster and in turn loose revs a lot faster-with the clutch disengaged) and engine braking during decelleration is noticeably increased aswell. I allready had the 8lb flywheel so I used it, but if I were to put another one in, it would be around 12lbs.

[rThor432]

slightly OT, but, is the rattle a M/S-50/52 problem or is it in the M-20's too?

Generally, it is an issue for any car with a light weight flywheel.

Not sure why I havent had any rattle from my M42 with the 8lb flywheel.. I also havent had any idle or take-off issues with any of the cars I've driven equipped with lightened flywheels and stock engine management.

[1990m3]

you guys must suck at "stick" i have ltw fly and i can take off in 3rd gear keeping rpm's under 1200

He speaks the truth. I have used a 3.46 and a 3.23 with my jb racing flywheel and it feels like a stock car on take off. I can start in 2nd or 3rd gear and it doesn't matter, smooth as silk with the revs very low or close to 1k RPM. My chip does account for the flywheel and raised the revs slightly to compensate. I love the flywheel, best bang for the buck mod I've ever had. I have one in my s14 car as well...love it in the 4-cylinder just as much

[416stroker]

+1, if you use, say a JB Racing M20 8lb flywheel, the idle will have to be increased. I think mine is @850-900rpm. The real advantage with a lightweight flywheel comes when you match revs during downshifts.(the engine will rev a lot faster and in turn loose revs a lot faster-with the clutch disengaged) and engine braking during decelleration is noticeably increased aswell. I allready had the 8lb flywheel so I used it, but if I were to put another one in, it would be around 12lbs.

What's an m50 suppsed to idle at mine idles at 500rpm.I can still idle out on a take off but it hesitates a little