Im running a 318is as a track car, does changing the flywheel for a lightened one make much difference ?
Any views on options/costs much appreciated
M42 flywheel upgrade
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Rav335uk
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It'll spin the engine quicker, less rotating mass ont he crank, but the downside is that it can feel lumpy on idle.
If you Got "Haters",Then your doing something Right!
CR24v??? Where's it all gone?? LOL
After reading up on a few articles of this myself it seems rather interesting. The gains would be in this case:
A: Quick of the line starts
B: Smoother at higher speeds (not sure)
c: Better fuel economy again not sure of this.
However what are the downsides of this upgrade apart from having a lumpy idle?
I have read up that most here on the zone quiet often will go with the M20 flywheel get that lightened and along with that comes the M20 Clutch and starter.
Now my question is after getting the m20 flywheel lightened and then attaching the m20 larger clutch, would this end up being heavier then the standard small m42 clutch and flywheel?
Just a thought thanks in advanced.
jon
A: Quick of the line starts
B: Smoother at higher speeds (not sure)
c: Better fuel economy again not sure of this.
However what are the downsides of this upgrade apart from having a lumpy idle?
I have read up that most here on the zone quiet often will go with the M20 flywheel get that lightened and along with that comes the M20 Clutch and starter.
Now my question is after getting the m20 flywheel lightened and then attaching the m20 larger clutch, would this end up being heavier then the standard small m42 clutch and flywheel?
Just a thought thanks in advanced.
jon
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Brianmoooore
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A straight comparison of the weights of the M20 and M42 flywheel is misleading. The bulk of the weight of the M42 version is in a big lump right around the outside - just where you don't want it for performance applications, so the advantage of using M20 components is greater than would appear at first sight.
Brianmoooore - I do remember reading up somewhere that downfalls include
general drive ability due to having less weight on the rear of the engine causing erratic idle which may cause inconsistent fuelling and or drink more fuel then necessary could this be the case?
Uphill starts and or rolling in traffic could possibly be a problem is this the case?
Trying to really weigh up the options of the advantages and disadvantages of this modification. It seems cost effective as it dose not seem to break the bank.
Thanks
general drive ability due to having less weight on the rear of the engine causing erratic idle which may cause inconsistent fuelling and or drink more fuel then necessary could this be the case?
Uphill starts and or rolling in traffic could possibly be a problem is this the case?
Trying to really weigh up the options of the advantages and disadvantages of this modification. It seems cost effective as it dose not seem to break the bank.
Thanks
I've been told....jon-m42 wrote:After reading up on a few articles of this myself it seems rather interesting. The gains would be in this case:
A: Quick of the line starts
B: Smoother at higher speeds (not sure)
c: Better fuel economy again not sure of this.
A: Yes, but at the expense of torque, so less smooth when pulling away/driving in traffic and when meeting a hill as there is less momentum from the lighter flywheel to keep the engine spinning.
B: I've been told that the car may surge and feel less smooth whilst cruising at speed due to the reduced spinning mass. BMW designed the flywheel to keep the car smooth so its at the optimal weight for that purpose.
C: Swings and roundabouts on that one I guess.
For a track car though, the above probably isn't so much of an issue.
A guy on M42club weighed the complete setups from M42 and M20, so flywheel and clutch kit. The site seems to be down at the moment, but IIRC they weighed within a couple kgs of each other.jon-m42 wrote: However what are the downsides of this upgrade apart from having a lumpy idle?
I have read up that most here on the zone quiet often will go with the M20 flywheel get that lightened and along with that comes the M20 Clutch and starter.
Now my question is after getting the m20 flywheel lightened and then attaching the m20 larger clutch, would this end up being heavier then the standard small m42 clutch and flywheel?
Just a thought thanks in advanced.
jon
I can't remember the outcome once flywheels had been lightened, but as Brian said above, you also need to consider where the weight is.
I've almost decided to go with a standard flywheel, mainly due to the fact mine is 95% daily driver, so I'd like to keep it fairly refined.
As the OP is looking for a track car, refinement may be less of an issue. I'd suggest looking at M42club once its back up.
James
'91 325i Sport
'93 318i touring 16v
'91 325i Sport
'93 318i touring 16v
Is there anybody on the zone who actually has done this simple yet effective Mod to their chariot?
I will be good to see what they can bring to light good and or bad things hey have experienced, although the change over between starter, clutch and flywheel can be easily done at a small cost but it will be interesting to know what they actually come up with..
I use the motor for mostly long drives and on weekends to town for the weekly shopping food etc. The child in me still wants to take her to santa pod and up the strip to:
A: See how quick/slow my time is
B: A weekend with a little fun driving
C: To get to know more and enjoy the sight seeing of e30's everywhere
D: starting to think a lightened flywheel could be of some what advantage off the line from stand still acceleration
I will be good to see what they can bring to light good and or bad things hey have experienced, although the change over between starter, clutch and flywheel can be easily done at a small cost but it will be interesting to know what they actually come up with..
I use the motor for mostly long drives and on weekends to town for the weekly shopping food etc. The child in me still wants to take her to santa pod and up the strip to:
A: See how quick/slow my time is
B: A weekend with a little fun driving
C: To get to know more and enjoy the sight seeing of e30's everywhere
D: starting to think a lightened flywheel could be of some what advantage off the line from stand still acceleration
I've done this modification to my M42, using the existing flywheel. When doing some research it was clear that the M20 flywheel upgrade was the most popular.
Instead I decided it would be cheaper to lighten the M40/42 flywheel than have to pay to buy and machine an M20 one as well as the cost of a different clutch and starter gear.
The photos show a standard M40/42 flywheel, on the right, next to my lightened one. The original weighed 9.3kg and after machining it was 7.4kg (-20%).
As you can see, the material has been removed from the outside circumference, axially, where it makes the greatest difference. The M20 flywheel is lightened in a different manner by removing material from the thickness, radially, between the ring gear and the engine-facing side (somebody else may be able to describe that better).
The tricky part with the M40/42 flywheel is that the only place you can remove significant material from is where you mount the clutch so you must be careful not to get carried away. Also be aware that this process will more than likely machine away any balancing holes (?) from when the wheel was originally balanced to the crankshaft. THis increases the chances of you ending up with an unbalanced flywheel (not good). Make sure you give it to a machine shop who know what they're doing.
A more extreme version of what I've done can be seen on the website of another zoner (rix313) who has done this:
http://www.visionracingdevelopments.co. ... ct-bmw.php
I'm sure there used to be a thread on here about this job but I can't find it.
It is a worthwhile modification as it has made a noticeable difference to the engine response and driveability without any negative effect on idle. Don't expect it to miraculously make your 318iS a fast car though. It won't.
Instead I decided it would be cheaper to lighten the M40/42 flywheel than have to pay to buy and machine an M20 one as well as the cost of a different clutch and starter gear.
The photos show a standard M40/42 flywheel, on the right, next to my lightened one. The original weighed 9.3kg and after machining it was 7.4kg (-20%).
As you can see, the material has been removed from the outside circumference, axially, where it makes the greatest difference. The M20 flywheel is lightened in a different manner by removing material from the thickness, radially, between the ring gear and the engine-facing side (somebody else may be able to describe that better).
The tricky part with the M40/42 flywheel is that the only place you can remove significant material from is where you mount the clutch so you must be careful not to get carried away. Also be aware that this process will more than likely machine away any balancing holes (?) from when the wheel was originally balanced to the crankshaft. THis increases the chances of you ending up with an unbalanced flywheel (not good). Make sure you give it to a machine shop who know what they're doing.
A more extreme version of what I've done can be seen on the website of another zoner (rix313) who has done this:
http://www.visionracingdevelopments.co. ... ct-bmw.php
I'm sure there used to be a thread on here about this job but I can't find it.
It is a worthwhile modification as it has made a noticeable difference to the engine response and driveability without any negative effect on idle. Don't expect it to miraculously make your 318iS a fast car though. It won't.
rust never sleeps
That looks good mrwhte.
Although i have thought about actually doing this to the current flywheel just as you have done but struggled to find information on this as nobody i could find had did this and now comes you
Is this safer then the m20 route as it is far cheaper i presume.
Although i have thought about actually doing this to the current flywheel just as you have done but struggled to find information on this as nobody i could find had did this and now comes you
Is this safer then the m20 route as it is far cheaper i presume.
I think the M20 one is easier (read safer) than the M40/42 to machine, that is probably why it is more popular.
It is cheaper to use the M42 flywheel but the machining still cost around £80 and I replaced the clutch anyway. The M42 clutch is like for like a bit cheaper than an M20 one but not by that much.
It is cheaper to use the M42 flywheel but the machining still cost around £80 and I replaced the clutch anyway. The M42 clutch is like for like a bit cheaper than an M20 one but not by that much.
rust never sleeps
is there a big difference in weight
once the m42 flywheel has been lightened how much would it weight with the added m42 clutch ?
and
once the m20 flywheel has been lightened how much would it weigh with the added m20 clutch ?
is there a big difference between the two?
and do you recommend any companies/garages who can perform the lightning and balancing with share quality??
once the m42 flywheel has been lightened how much would it weight with the added m42 clutch ?
and
once the m20 flywheel has been lightened how much would it weigh with the added m20 clutch ?
is there a big difference between the two?
and do you recommend any companies/garages who can perform the lightning and balancing with share quality??
You can probably answer your own questions by doing a search on here. Flywheel weights are talked about quite often. Clutch kit weights are probably stated on the manufacturer information, unless somebody has the figures to hand and can comment. I'd guess that the total flywheel+clutch weights would be fairly similar when compared.jon-m42 wrote:is there a big difference in weight
once the m42 flywheel has been lightened how much would it weight with the added m42 clutch ?
and
once the m20 flywheel has been lightened how much would it weigh with the added m20 clutch ?
is there a big difference between the two?
and do you recommend any companies/garages who can perform the lightning and balancing with share quality??
Regarding machining companies to do the work, it really depends where you are, but you shouldn't have to look far to find a machine shop who routinely do automotive work - head skimming and engine work etc.
I had mine done in Glasgow by West of Scotland Engineering.
rust never sleeps
Mrwhite firstly love your zone id name lol
secondly I am located in Essex near Romford. I have not a clue where to go or who to go to get such work done.
There are a few garages around the area however i do not know any who have done this before or any other specialist engineering shop who can take this on like a piece of cake.
Is there anybody on the zone who can recommend a good garage/engineering shop who has done this before in and around east london?
secondly I am located in Essex near Romford. I have not a clue where to go or who to go to get such work done.
There are a few garages around the area however i do not know any who have done this before or any other specialist engineering shop who can take this on like a piece of cake.
Is there anybody on the zone who can recommend a good garage/engineering shop who has done this before in and around east london?
As standard, the complete setup (flywheel, clutch and release bearing) weigh almost the same, M42 - 15.5kg, M20 - 15.48kg (info from M42club)jon-m42 wrote:is there a big difference in weight
once the m42 flywheel has been lightened how much would it weight with the added m42 clutch ?
and
once the m20 flywheel has been lightened how much would it weigh with the added m20 clutch ?
is there a big difference between the two?
Looking at the posts above, I think we can say an M42 flywheel can be taken down to roughly 7kg.
I seem to remember people on here saying 5.6kg is the lightest for an M20 flywheel, but reckon on 6kg for safety.
So all in, about a 1kg-1.5kg difference once lightened.
James
'91 325i Sport
'93 318i touring 16v
'91 325i Sport
'93 318i touring 16v
I did this on mine aswell as I didn't know about the m20 flywheel mod at the time. But saying that I wouldn't have wanted to buy a new flywheel and clutch either. Got about 1kg maybe less taken off from the outer edge of the fly wheel. (Can't remember exact weight)
I did it at the same time as swapping from a m40 to m42 so couldn't compare the difference. All I can say is the idle is slightly lumpy but nothing to worry about. I wouldn't say it stalls much easier but maybe I'm just used to it? Does rev up nicely though! I think the clutch also bites a bit harder like a racing clutch, but only slightly.
I did it at the same time as swapping from a m40 to m42 so couldn't compare the difference. All I can say is the idle is slightly lumpy but nothing to worry about. I wouldn't say it stalls much easier but maybe I'm just used to it? Does rev up nicely though! I think the clutch also bites a bit harder like a racing clutch, but only slightly.
'89 Lachsilver m42 coupe - Sold
'92 Laguna Green Convertible M50
'97 e36 328i sport - Daily
'89 Alfa Romeo Sprint cloverleaf
'92 Laguna Green Convertible M50
'97 e36 328i sport - Daily
'89 Alfa Romeo Sprint cloverleaf
Well i guess the questio now is which to go for ?
The m20 flywheel with its larger rotating mass helps with smooth running a higher speeds.
The m42 nothing extra is needed as all the cluth starter is all there, however has a smaller rotating mass.
Which would be better to ;lighten and install?
I do nto mind pay for the extra clutch kit and starter if it means its going to add and or be more of a benifit to the overall perfomance and drve.
The m20 flywheel with its larger rotating mass helps with smooth running a higher speeds.
The m42 nothing extra is needed as all the cluth starter is all there, however has a smaller rotating mass.
Which would be better to ;lighten and install?
I do nto mind pay for the extra clutch kit and starter if it means its going to add and or be more of a benifit to the overall perfomance and drve.
Are you doing all the work yourself? Seems a pointless exercise if you're paying a garage to do it, that's a lot of money that could be better spent elsewhere, a few replacement bushes and a good service would return better driving experience results.
The only reason the M20 is mentioned so much is because it's a requirement for the M50/2 install so it's a tried and tested method. Haven't seen too many people on here mention lightening an M42 flywheel.
The only reason the M20 is mentioned so much is because it's a requirement for the M50/2 install so it's a tried and tested method. Haven't seen too many people on here mention lightening an M42 flywheel.
I fitted an m20 flywheel to my IS. I had it skimmed for the new 325i clutch and then i had some weight cut out of the back too. I did a like for like weight test of the m42 flywheel and clutch combo vs the m20 lightened flywheel and clutch setup and there wasnt a huge difference, but as others have pointed out, on the m20 setup you have less mass farther away from the centre of rotation and it made a big difference. I used the car for sprint racing, and as a daily. I would recommend it. I didnt see any downsides at all.
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rix313
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Looks like I got the standard weight wrong when I wrote that, oops. I had that done by a local machine shop then sent it away to an engine specialists who then balanced it for me.MrWhite wrote: A more extreme version of what I've done can be seen on the website of another zoner (rix313) who has done this:
http://www.visionracingdevelopments.co. ... ct-bmw.php
I'm sure there used to be a thread on here about this job but I can't find it.
The potential problem with what I've had done and I'm not ashamed to admit it is I may have had too much taken out and subsequently reduced to overall integrity and strength of the flywheel. I don't fancy dropping the clutch on the start line and having it fail. I have however been speaking to a company in the UK who machine billet flywheels and they do a replacement lightweight flywheel at around 5kg which I'm looking into.
Last edited by rix313 on Tue Sep 03, 2013 9:03 pm, edited 1 time in total.
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AdamGardner
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where did you get that from?
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AdamGardner
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what sort of clutch will that take? ideally want a paddle clutch set up for my rally car build
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rix313
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That one is for a standard size clutch, you can buy paddle plates to fit the standard flywheel and clutch cover, they're about £160. They do a flywheel for the small motorsport clutches as well though.
Have you fitted it yet? Im thinking of fitting an aluminum flywheel sold as a direct replacement for the m42 flywheel...
http://www.turnermotorsport.com/p-3769- ... wheel.aspx
Anyone tried this?
http://www.turnermotorsport.com/p-3769- ... wheel.aspx
Anyone tried this?
http://www.turnermotorsport.com/p-3769- ... wheel.aspx
Stock Flywheel Weight = 27.0lbs
JB Flywheel Weight = 9.0lbs
This item fits the following BMWs:
1989-1992 E30 BMW 318i 318is 318ic
1992-1997 E36 BMW 318i 318is 318ti 318ic
1996-1997 Z3 BMW Z3 1.9
Shipping Dimensions: 12 X 12 X 6
Shipping Weight: 11.00
Price: $629.95 (USD
Stock Flywheel Weight = 27.0lbs
JB Flywheel Weight = 9.0lbs
This item fits the following BMWs:
1989-1992 E30 BMW 318i 318is 318ic
1992-1997 E36 BMW 318i 318is 318ti 318ic
1996-1997 Z3 BMW Z3 1.9
Shipping Dimensions: 12 X 12 X 6
Shipping Weight: 11.00
Price: $629.95 (USD
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rix313
- E30 Zone Team Member
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They are a good, happy with mine although it needed modifying. They did the work and were quick at turning it round. This is from my race car thread:
Credit where credit is due, TTV turned around my flywheel pretty quickly all things considered and it arrived back today. They machined the mounting holes to accept the bolts with the perfect amount of tolerance for a socket. I can't bolt it on as my bits from BMW haven't arrived but I have a weekend lined up to nail it. This is before:
This is after:
Credit where credit is due, TTV turned around my flywheel pretty quickly all things considered and it arrived back today. They machined the mounting holes to accept the bolts with the perfect amount of tolerance for a socket. I can't bolt it on as my bits from BMW haven't arrived but I have a weekend lined up to nail it. This is before:
This is after: