Author Topic: The real lightened flywheel benefit...? (Read 7601 times)

M42_Jester · « **on:** November 02, 2011, 06:08:06 AM »

ok...so what are the actual benefits of having a lightened flywheel? are there noticeable differences?

about to get a lightened flywheel and 228mm clutch assembly from MM and was just wondering what the real benefits are. will also be asking my mechanic about this...so more just after some thoughts

Cheers,

Jester

romkasponka · « **Reply #1 on:** November 02, 2011, 07:39:46 AM »

http://www.zf.com/media/media/document/corporate_2/products_3/motorsports_1/product_range_motorsports/catalogue/sachs-racing/RCS_zf.pdf

page 11, clutch mass comparisons and benefits

Geoff · « **Reply #2 on:** November 02, 2011, 08:31:30 AM »

basicly, your engine will rev up faster, with less weight in the rotating mass assy. also lose revs faster. may exhibit additional roughness at idle, as one of the reasons for some weight on the flywheel, is to smooth the idle. May also need a little blip on the throttle from an idle, as it wont have the weight where it used too, to take off smoothly. these are just my impressions from having driven cars with lightened flywheels, the effect depends of course on how light you go. I personally dont feel the need to lighten flywheels on everyday drivers, but do on track cars or toys that dont see everyday use. your experience may differ.
Geoff

91 e30m42 · « **Reply #3 on:** November 02, 2011, 04:20:05 PM »

Quote from: Geoff;107824

basicly, your engine will rev up faster, with less weight in the rotating mass assy. also lose revs faster. may exhibit additional roughness at idle, as one of the reasons for some weight on the flywheel, is to smooth the idle. May also need a little blip on the throttle from an idle, as it wont have the weight where it used too, to take off smoothly. these are just my impressions from having driven cars with lightened flywheels, the effect depends of course on how light you go. I personally dont feel the need to lighten flywheels on everyday drivers, but do on track cars or toys that dont see everyday use. your experience may differ.
Geoff

Well ive been having mines ever since the new engine and my idle is smooth, no need to feather the throttle to go from zero.. i can let the clutch out slowly to start rolling with out problems basically... i have all the benefits of a light weight flywheel without the negative side effects.. could it depend on the weight as mine is rated at 9 lbs... and it is my daily driver

Geoff · « **Reply #4 on:** November 02, 2011, 04:48:02 PM »

I didnt say that those things would happen, I said they may. :cool: these are pretty well known down-sides to a lightened flywheel, but maybe the effect is not as much on a M42 motor.
Geoff

91 e30m42 · « **Reply #5 on:** November 02, 2011, 05:09:53 PM »

Quote from: Geoff;107836

I didnt say that those things would happen, I said they may. :cool: these are pretty well known down-sides to a lightened flywheel, but maybe the effect is not as much on a M42 motor.
Geoff

well youre not the only one that have said that these have happened on their car when they put a lightweight fly wheel on (not saying that you have one as i believe yuo have stated that you dont have a lwf) .. i havent experienced none of these negative effects on mine and i daily drive my car when i get the chance..
maybe it depends on the set up as i hear ppl here used the 323 layout or so...
thats why i would recommend the lightweight flywheel but i went with the JB racing one so i cant say for the other lightweight flywheel conversions or set ups ....

M42_Jester · « **Reply #6 on:** November 03, 2011, 02:50:27 AM »

the MM Lightweight Flywheel and 228mm Clutch Assembly is the one i have chosen to go with, purely based on the fact that it is designed for the M42 without the need for modifications for it to work. it weighs 11 - 11.5lbs and the 228mm clutch is rated up to 230ft. lbs of torque...

cost: USD$975 + USD$225 freight
total = USD$1200

the other lightweight flywheels i have looked at for the M42 are close to $900 by themselves, and required a 240mm OEM M3 clutch for fitment (which is a further $400)

there is the option of getting the a 240mm Clutch + 240mm Lightweight flywheel assembly, and for only an extra USD$75...

out of these 2 options...which would be better suited?

FYI: future plans for the car include a 2.1 MM M42 and a DASC...

Cheers,

Jester

91 e30m42 · « **Reply #7 on:** November 03, 2011, 10:50:10 AM »

JESTER,
well if that sounds good go for it the better the fitment will be the less negative side effects you will get.. i went with sachs oem clutch because my M42 wont be rated at that much torque anyways unless i go turbo which it wont be for a while... personally i like my set up no worries in every day driving and no slippage for the spirted canyon carving as well.. and this is my set up
http://www.turnermotorsport.com/p-3769-e30-318i-e36-318i-z3-19-jb-racing-aluminum-flywheel.aspx

http://www.turnermotorsport.com/p-4182-e30-e36-318-clutch-kit-for-cars-with-ac.aspx
i dont have A/C in my car i took it out but the clutch kit still works..

this is only my opinion and not a recommendation which i believe is what your looking for...

wazzu70 · « **Reply #8 on:** November 03, 2011, 11:14:47 AM »

Quote from: Geoff;107824

basicly, your engine will rev up faster, with less weight in the rotating mass assy. also lose revs faster. may exhibit additional roughness at idle, as one of the reasons for some weight on the flywheel, is to smooth the idle. May also need a little blip on the throttle from an idle, as it wont have the weight where it used too, to take off smoothly. these are just my impressions from having driven cars with lightened flywheels, the effect depends of course on how light you go. I personally dont feel the need to lighten flywheels on everyday drivers, but do on track cars or toys that dont see everyday use. your experience may differ.
Geoff

This is spot on. I daily my car with a 323 flywheel and its not bad, but the idle is a little more rough and the flywheel loses momentum fast. Can be a bit of a pain on hills, but its not bad at all. Car revs like a dream though

I track my car as well and the LTW flywheel comes in handy there.

Boyracer · « **Reply #9 on:** November 04, 2011, 06:24:08 AM »

I have this:

In total 6,5 kg or 14,5 lbs.

Noticeable difference on how engine revs up or down. Gear changes down are faster because you don't have to wait engine to lose revs. Also engine gains revs faster when you engage clutch after downshift, good for braking to turns.

I changed diff ratio 3.45 -> 4.1 at the same time so cannot really compare how much difference it does on acceleration. Car seems much more eager to go on 1st and 2nd gears.

91 e30m42 · « **Reply #10 on:** November 04, 2011, 01:04:09 PM »

Quote from: Boyracer;107881

I have this:

In total 6,5 kg or 14,5 lbs.

Noticeable difference on how engine revs up or down. Gear changes down are faster because you don't have to wait engine to lose revs. Also engine gains revs faster when you engage clutch after downshift, good for braking to turns.

I changed diff ratio 3.45 -> 4.1 at the same time so cannot really compare how much difference it does on acceleration. Car seems much more eager to go on 1st and 2nd gears.

what clutch set up you running

Hey-u · « **Reply #11 on:** November 04, 2011, 01:36:10 PM »

This is my set up:
- SACHS Clutch disk 1861661133228
- SACHS Pressure plate TYP MF 228
- Aasco motorsports Lightweight flywheel 100811-11 (11lbs)
It's hard for me to tell how much difference it makes because it was installed at the same time as my SC motor. I would say that the car was more pleasant to drive with the heavier flywheel and requires more attention with the lightened one. My wife would think it is stupid but I think it was the correct choice for my set up. My opinion might change if I had to daily drive.

91 e30m42 · « **Reply #12 on:** November 04, 2011, 02:45:26 PM »

Quote from: Hey-u;107888

This is my set up:
- SACHS Clutch disk 1861661133228
- SACHS Pressure plate TYP MF 228
- Aasco motorsports Lightweight flywheel 100811-11 (11lbs)
It's hard for me to tell how much difference it makes because it was installed at the same time as my SC motor. I would say that the car was more pleasant to drive with the heavier flywheel and requires more attention with the lightened one. My wife would think it is stupid but I think it was the correct choice for my set up. My opinion might change if I had to daily drive.

how much did you spend for your SC set up... im debating whether i go SC or turbo

Hey-u · « **Reply #13 on:** November 06, 2011, 12:31:03 PM »

Quote from: 91 e30m42;107889

how much did you spend for your SC set up... im debating whether i go SC or turbo

Hard to put a price on it but if I was to do it again I don't think I would not go Megasquirt. I would buy the DASC package and run with stock motronic. $2k in tunning alone hasn't got me to a perfect world. I really like the SC set up and I'm glad I went that route but turbo will bring more HP for less$

91 e30m42 · « **Reply #14 on:** November 07, 2011, 11:08:19 AM »

Quote from: Hey-u;107918

Hard to put a price on it but if I was to do it again I don't think I would not go Megasquirt. I would buy the DASC package and run with stock motronic. $2k in tunning alone hasn't got me to a perfect world. I really like the SC set up and I'm glad I went that route but turbo will bring more HP for less$

i understand that but i would like it to pass smog as well to keep it street driven and well sc here in Cali is street legal but turbo is a little more harder if not came from factory... they both nice set ups as i would love a turbo but still debating but thanks for your input