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Discussion Starter #1
So, this E39 M5 I recently picked up (I transitioned from an E46 M3) had some issues when I bought it. The issues were all small things (minus the clutch) and this didn't bother me since I practically stole the car for what I paid for it.

Anyways, the clutch is going out. I can tell because when I really get on it on the highway it will shoot up in RPMs until it catches. It only does this under WOT.

Since I'm going to pay the dealer to put in a new clutch (they told me roughly $2000 for a new clutch, resurfaced flywheel, and the labor) I figured maybe it would be a good time to upgrade, the problem is I'm not sure I need to.

I've taken a look at the UUC flywheel / clutch packages and they seem a bit extreme. First off they seem way too light for a street driven car (that's the key here, this car is 100% street driven, no track whatsoever) and I don't like the idea of rattling or gear lash at idle. On top of that, the price is out of this world.

So, I'm curious, is there some sort of happy medium here? Maybe a flywheel that's just a bit lighter than stock but not overkill? Can the stock flywheel on these cars be lightened enough to make a difference or is it even worth it?

As I said before, this car is a street driven car. I have no interest in racing it or getting myself up for rattles, gear lash, chattering clutches, etc. I want it to drive like a well behaved car.

Perhaps my best option is the stock clutch and flywheel which I'm not opposed to at all. I'm just trying to see what my best options are first. I know back when I was much younger and working on VWs you could just take the flywheel into a machine shop and have them 'lighten' it. Not sure if that's possible on these cars, but who knows?
 

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I just installed the South Bend Stage 3 daily clutch in my car, so far it's great. Pedal pressure is stiff but that's to be expected with stage 3 (I'm supercharged that's why I went stage 3). However as far an engagement and grip go I'd rate it 9.9/10 so far. For your application stage one or two would be appropriate.

Flywheel I have noticed that most people stay with the stock DMF. I did and even on my setup it's great, no chatter and smooth engagement.

ECS News BMW E39 M5 South Bend Clutch Kits - K70282HDO - Stage 2 Daily Clutch Kit - ES#2725258

ECS News BMW E39 M5 South Bend Clutch Kits - K70282HD - Stage 1 Heavy Duty Clutch Kit - ES#2725141
 

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So, this E39 M5 I recently picked up (I transitioned from an E46 M3) had some issues when I bought it. The issues were all small things (minus the clutch) and this didn't bother me since I practically stole the car for what I paid for it.

Anyways, the clutch is going out. I can tell because when I really get on it on the highway it will shoot up in RPMs until it catches. It only does this under WOT.

Since I'm going to pay the dealer to put in a new clutch (they told me roughly $2000 for a new clutch, resurfaced flywheel, and the labor) I figured maybe it would be a good time to upgrade, the problem is I'm not sure I need to.

I've taken a look at the UUC flywheel / clutch packages and they seem a bit extreme. First off they seem way too light for a street driven car (that's the key here, this car is 100% street driven, no track whatsoever) and I don't like the idea of rattling or gear lash at idle. On top of that, the price is out of this world.

So, I'm curious, is there some sort of happy medium here? Maybe a flywheel that's just a bit lighter than stock but not overkill? Can the stock flywheel on these cars be lightened enough to make a difference or is it even worth it?

As I said before, this car is a street driven car. I have no interest in racing it or getting myself up for rattles, gear lash, chattering clutches, etc. I want it to drive like a well behaved car.

Perhaps my best option is the stock clutch and flywheel which I'm not opposed to at all. I'm just trying to see what my best options are first. I know back when I was much younger and working on VWs you could just take the flywheel into a machine shop and have them 'lighten' it. Not sure if that's possible on these cars, but who knows?
The only setup that won't display any rattle is one that utilizes the dual mass flywheel. Forget about the UUC the JB setup all those with a solid flywheel will produce uncharacteristic noise. We have had four client E39 M5s and one E39 540i that have had solid flywheel clutch kits installed and within 6 months of installation each vehicle was converted back to the OEM setup. The reason for the change back had to do with noise and in some of the cases premature clutch failure (UUC kit). Keep in mind the customer had to pay for labor twice in this scenario. That being said you can install a lightened dual mass flywheel. Both Dinan and CNS offer this setup. I can vouch for the Dinan setup (we have installed two kits on clients vehicle) and can say it's a great system. There is a noticeable difference in revving up with the modified lightened flywheel but with no drawback of noise or chatter that would be encountered with other aftermarket setups. I cannot vouch for the CNS system because we have never installed this on any clients vehicle but their setup looks similar to the Dinan. If I were to go outside the Dinan setup I would use a modified Dual Mass Flywheel with a southbend clutch.

By the way there is no resurfacing of the dual mass flywheel. The dealer should advise you that the Dual Mass Flywheel will be changed at the time of the clutch change out.
 

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FWIW my flywheel was in perfect shape after 130K, I felt guilty changing it. No additional play between the two halves vs. a brand new one and machining marks in the surface still totally crisp and perfect. Unless there is a problem with it I wouldn't be so quick to change the DMF as a wear item.
 

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Discussion Starter #6 (Edited)
Got it, you guys shed some light on this for me.

So, to get my facts straight:

1) You can't lighten the factory dual mass flywheel
2) You can't resurface the factory dual mass flywheel (you just need to buy a new one instead?)
3) Solid flywheel kits (i.e. UUC) are going to produce noise no matter what in comparison to a DMF?

I've heard horror stories about the UUC kits anyways. Some people love them while other people hate them. Bottom line is from what I've read a lot of guys who go the solid flywheel route (i.e. UUC) end up switching back to a dual mass flywheel. Although I've never been in that situation I can imagine. To me, an expensive car like the M5 shouldn't be chattering at idle or making noise from the flywheel, that just seems annoying.

I'll look into the Dinan or CNS flywheel with a Southbend clutch!

By the way, how do you guys like these Southbend clutch kits? From what I read about the stock M5 clutch it seems like a weak point and a bit 'under-designed' for this particular car. Do these Southbend kits offer a similar feel to stock while being a little more 'capable' in regards to handling the power of the car?
 

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Got it, you guys shed some light on this for me.

So, to get my facts straight:

1) You can't lighten the factory dual mass flywheel
No. Dinan does and CNS does. The difference is Dinan takes some weight out ( I think about 8 lbs) and the stock DMF mates to the stock size disc.

CNS machines the surface to allow a bigger surface area and hence a bigger (10.5 inch disc vs. 9. 625 inch disc). I am not sure how much weight they remove. Where weight is removed is just as important as how much (removing less weight at the outside is more effective).

2) You can't resurface the factory dual mass flywheel (you just need to buy a new one instead?)
In the past conventional wisdom is you may be able to get a second use out of the DMF. If the clutch has overheated the DMF (the self adjusting mechanism is the issue here), then you are better off with a new DMF. If you have a ton of miles, you may also be better off. The price of the DMF has come down over time. If you are paying for labor, you want to be SURE the used DMF (after being scuffed up a bit) will work; otherwise it is cheaper to just buy new and be done with it.

3) Solid flywheel kits (i.e. UUC) are going to produce noise no matter what in comparison to a DMF?
That has been the collective experience here.

I've heard horror stories about the UUC kits anyways. Some people love them while other people hate them.
If you track the car and have increased the power, this is one of the best setups. You won't care about gear lash, and the system SHOULD be robust. My CNS 10.5 DMF seems robust also, holding up easily on the street with well over 550 hp. I have had no issues with it (although I have not taken the car to the track).


To me, an expensive car like the M5 shouldn't be chattering at idle or making noise from the flywheel, that just seems annoying.
That was my feeling. After all, this is a street car, and a luxury one at that.
From what I read about the stock M5 clutch it seems like a weak point and a bit 'under-designed' for this particular car.
Yes. It may have been intentional, as the weak link in a drivetrain that will fry a clutch before anything else breaks. But the 540, putting out about 115 LESS hp, uses the same setup. If you are running stockish power levels, and don't abuse the clutch (such as dumping the clutch from a standstill on a regular basis) , the stock setup (or southbend upgrade with no SAC and better PP) will do just fine IMHO.

Regards,
Jerry
 

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The CNS DMF is 11 pounds lighter than stock (I have the CNS 10.5 clutch/DMF)

Love it, but not sure I'd buy from them again due to some questionable practices in the past...
 

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I went the completely stock route when I did my clutch (80k miles on the car). I didn't need a new flywheel so I just replaced the clutch with the OEM LUK clutch. I am happy as can be, it drive just as it should, smooth. The factory clutch can certainly take the power that a stock M5 can put out, but there are clutches that will last longer at that power level then the stock clutch.

I am happy with what I did and I can't imagine anyone that wants a nice driving M5 would have any regrets replacing their clutch with a stock clutch.
 

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Discussion Starter #10
No. Dinan does and CNS does. The difference is Dinan takes some weight out ( I think about 8 lbs) and the stock DMF mates to the stock size disc.

CNS machines the surface to allow a bigger surface area and hence a bigger (10.5 inch disc vs. 9. 625 inch disc). I am not sure how much weight they remove. Where weight is removed is just as important as how much (removing less weight at the outside is more effective).



In the past conventional wisdom is you may be able to get a second use out of the DMF. If the clutch has overheated the DMF (the self adjusting mechanism is the issue here), then you are better off with a new DMF. If you have a ton of miles, you may also be better off. The price of the DMF has come down over time. If you are paying for labor, you want to be SURE the used DMF (after being scuffed up a bit) will work; otherwise it is cheaper to just buy new and be done with it.



That has been the collective experience here.



If you track the car and have increased the power, this is one of the best setups. You won't care about gear lash, and the system SHOULD be robust. My CNS 10.5 DMF seems robust also, holding up easily on the street with well over 550 hp. I have had no issues with it (although I have not taken the car to the track).




That was my feeling. After all, this is a street car, and a luxury one at that.


Yes. It may have been intentional, as the weak link in a drivetrain that will fry a clutch before anything else breaks. But the 540, putting out about 115 LESS hp, uses the same setup. If you are running stockish power levels, and don't abuse the clutch (such as dumping the clutch from a standstill on a regular basis) , the stock setup (or southbend upgrade with no SAC and better PP) will do just fine IMHO.

Regards,
Jerry
Thanks for all that info, it helps!

I've read about numerous people having their stock clutch setups last over 100k. I suspect I could easily be one of those people since I never dump the clutch, I don't drag race, and I don't take it to the track either. For me it's just a fun weekend car that we take on long highway trips and what not.

However, it does sound discouraging that the same clutch is used in the 540i which has significantly less horsepower. There's two clutches I'm looking at (aside from stock) and those are as follows:

ECS News BMW E39 M5 South Bend Clutch Kits - K70282HDO - Stage 2 Daily Clutch Kit - ES#2725258
FX Racing Stage 2 Rigid Clutch Kit 2000-03 BMW M5 E39 Z8 E52 S62B50 4.9L V8 DOHC

Now, the Gripforce clutch is significantly cheaper and seems to be rated for higher horsepower than stock while still being a good street solution. I question the cost of some of these aftermarket clutches as I suspect some of them are made by the same supplier just branded with different names and therefore higher prices. I know this is the case with automotive batteries. There are only a handful of battery makers, but once they apply a brand name to them they sell them for more regardless of if they're made by the same manufacturer.

I'm just going to go with the LUK DMF flywheel (the stock one). I found it for $387 brand new which is a good deal. My car has 165k and while they are all easy miles, I know it's the stock flywheel in there so any attempt to resurface it would be pointless when I can get a new flywheel for such a cheap price.

I guess all it comes down to now is the clutch. I have no big power plans for this car. I plan on getting an Evolve Tune, Evolve headers, and maybe down the road some Shrick cams and some headwork. That's it though, I won't go beyond that. So, in the end I suspect my car would never see more than 400rwhp (with all of those mods) on a very good day.
 

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Thanks for all that info, it helps!

I've read about numerous people having their stock clutch setups last over 100k. I suspect I could easily be one of those people since I never dump the clutch, I don't drag race, and I don't take it to the track either. For me it's just a fun weekend car that we take on long highway trips and what not.

However, it does sound discouraging that the same clutch is used in the 540i which has significantly less horsepower. There's two clutches I'm looking at (aside from stock) and those are as follows:

ECS News BMW E39 M5 South Bend Clutch Kits - K70282HDO - Stage 2 Daily Clutch Kit - ES#2725258
FX Racing Stage 2 Rigid Clutch Kit 2000-03 BMW M5 E39 Z8 E52 S62B50 4.9L V8 DOHC

Now, the Gripforce clutch is significantly cheaper and seems to be rated for higher horsepower than stock while still being a good street solution. I question the cost of some of these aftermarket clutches as I suspect some of them are made by the same supplier just branded with different names and therefore higher prices. I know this is the case with automotive batteries. There are only a handful of battery makers, but once they apply a brand name to them they sell them for more regardless of if they're made by the same manufacturer.

I'm just going to go with the LUK DMF flywheel (the stock one). I found it for $387 brand new which is a good deal. My car has 165k and while they are all easy miles, I know it's the stock flywheel in there so any attempt to resurface it would be pointless when I can get a new flywheel for such a cheap price.

I guess all it comes down to now is the clutch. I have no big power plans for this car. I plan on getting an Evolve Tune, Evolve headers, and maybe down the road some Shrick cams and some headwork. That's it though, I won't go beyond that. So, in the end I suspect my car would never see more than 400rwhp (with all of those mods) on a very good day.

Remember, just hp is not that hard on a clutch once you are moving. And if you heel and toe (rev matching) when pushing the car, you take the strain off the synchros.

I think the real weak link in the stock setup is the self adjusting mechanism (SAC). I suspect that if you replace the pressure plate and disc without the SAC and you are an intelligent driver, you will be fine. At under $400, I would get the new DMF.

As to power plans, if you get to 400 at the wheels, that is basically Dinan S2 level, about 470 at the crank. That is pretty healthy.

I am pleased with my CNS notwithstanding the questionable marketing practices. It does not take away from the quality or design of the product.

Regards,
Jerry
 

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Discussion Starter #13
I always, always, always rev match between shifts, that's just a habit I've been in since I was a kid. So, that's no an issue at all.

I'm going to go with the factory LUK DMF flywheel and one of these clutch kits. I'm worrying too much about having some high horsepower clutch when in reality the most I'll ever see is 400 at the wheels, and even then, I won't be driving it like some teenager.
 

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FWIW my flywheel was in perfect shape after 130K, I felt guilty changing it. No additional play between the two halves vs. a brand new one and machining marks in the surface still totally crisp and perfect. Unless there is a problem with it I wouldn't be so quick to change the DMF as a wear item.
I would agree that depending on the clutch wear not all dual mass flywheels have to be changed; however when we get a client's car that needs a clutch change on these bmw e39s and they have over 120k we recommend changing the DMF at time of the clutch. It's a good piece of mind measure.
 

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It is a solid bit of kit, I have 45K miles on mine...
By the way does your CNS clutch and flywheel kit work and sound like stock?meaning no rattle at idle or clutch chatter upon engagement?

Regards

Jay
 

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Indeed it does, no chatter at all, ever. CNS takes the stock dual mass flywheel and shaves it down to remove the weight, so you're left with all the benefits of a dual mass, but much lighter than stock kit.
 

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Discussion Starter #17
If all CNS is doing is taking the stock flywheel and shaving it to remove weight, it seems a bit crazy that they would charge $1600 for it:
BMW E39 M5 CNS Racing Lightweight Dual-Mass Flywheel for OEM Clutch

Am I wrong in thinking that? I mean I can get the stock LUK dual mass flywheel for under $400. Couldn't I just take that to a machine shop and have them lighten it, or am I missing something?
 

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If all CNS is doing is taking the stock flywheel and shaving it to remove weight, it seems a bit crazy that they would charge $1600 for it:
BMW E39 M5 CNS Racing Lightweight Dual-Mass Flywheel for OEM Clutch

Am I wrong in thinking that? I mean I can get the stock LUK dual mass flywheel for under $400. Couldn't I just take that to a machine shop and have them lighten it, or am I missing something?
Dinan charges a similar amount. There's a thread on here somewhere with the machining dimensions, but I don't know if anyone has ever gone that route... should certainly be possible though.
 
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