M44 Dual Mass to Single Mass and Beyond

[zedonist]

It comes down to degrees of slip and grip Jim, the more power you put through a clutch the more it slips, you therefore have to either put greater back pressure on the clutch with a stronger sprung back plate, or change to a more grippy friction material such as Kevlar or do both, obviously heat is a contributing factor and steel flywheels hold the heat and will degrade a drag racing clutch rapidly, an aluminium flywheel acts as heat sink and draws the heat away, so has an advantage over steel, structurally aluminium can be heat treated to the same strength as steel ones (6000 series) and 7000 series alloys to even greater strengths, but may have a weaker shock performance so perhaps not the best choice for dragging,

 

[EnthuZiaZT]

I can think of several potential problems, wear as already stated would be my main concern. After all aluminium in what ever grade is still comparatively a soft material. I would have thought that it would be better to buy a single mass flywheel and lighten that. Or leave the flywheel alone and look at turbo charging the engine. Which would give similar results.

Mike

 

[oldcarman]

It comes down to degrees of slip and grip Jim, the more power you put through a clutch the more it slips, you therefore have to either put greater back pressure on the clutch with a stronger sprung back plate, or change to a more grippy friction material such as Kevlar or do both, obviously heat is a contributing factor and steel flywheels hold the heat and will degrade a drag racing clutch rapidly, an aluminium flywheel acts as heat sink and draws the heat away, so has an advantage over steel, structurally aluminium can be heat treated to the same strength as steel ones (6000 series) and 7000 series alloys to even greater strengths, but may have a weaker shock performance so perhaps not the best choice for dragging,

Thanks Rich, that's why we decided to go with an automatic for the drag car the school kids are building. We figured with so many different drivers getting to use it a clutch would just be too tortured. JIM

 

[oldcarman]

I can think of several potential problems, wear as already stated would be my main concern. After all aluminium in what ever grade is still comparatively a soft material. I would have thought that it would be better to buy a single mass flywheel and lighten that. Or leave the flywheel alone and look at turbo charging the engine. Which would give similar results.

Mike

Hi Mike, all the best for the holidays to you and Sandy! I've been thinking along the same lines as Zedonist since before my car ever arrived from the UK. I tossed turbo/ supercharging around but decided it was just to difficult to make either appear like they came from the factory that way. Lightening that DM clutch looked like a way out but after showing the info I had to a friend it was decided it wasn't quite that easy to do. Have been looking into swapping transmissions and rear gearing but certainly not with the expertise Zed has. I look forward to seeing this as it plays out. JIM
Hit the button too soon. I'm also considering going with NOS as a quick easy to accomplish solution. The little 1.9 appears stout enough for a fairly good hit of nitrous if the body can hold together.

 

[zedonist]

I can think of several potential problems, wear as already stated would be my main concern. After all aluminium in what ever grade is still comparatively a soft material. I would have thought that it would be better to buy a single mass flywheel and lighten that. Or leave the flywheel alone and look at turbo charging the engine. Which would give similar results.

Mike

Mike,

Thanks for the comments, I dont want this to turn into a thread of reasons not to do it, it is happening as we speak, the answers to your questions are posted back up earlier in the thread. But I will post again below:

A turbo or DASC costs circa £2000 plus to fit, this costs less than £200,

I bought a steel single mass, but it does not have the potential to have enough material removed and be safe, therefore an Aluminium one of the same dimensions exactly to the steel one, will reduce weight and still be dimensionally correct as per OEM conditions.

Aluminium in its pure form 99% or series 1000 is very soft, however series 2000 upwards are alloys of Aluminium and can all be heat treated to the same strength as steel so there is not an issue with hardness or strength. That said aluminium does not provide the correct surface characteristics for working as a clutch surface and a hardened steel clutch plate is bolted to the aluminium fly wheel and the friction material of the clutch acts upon this surface the same as a cast iron or steel fly wheel.

The steel plate will wear and need cleaning up or replacing, but this is no different to any steel fly wheel.

Again this is not new technology it has been around for many years, a number of road cars had an aluminium fly wheel as standard, and it is used in a lot of performance car engines and race cars today and actually race approved in some classes for dragging, you can Aldo buy them off the shelf, but with shipping etc are more expensive than getting one made in the UK.

This fly wheel is being made out of 6000 series aluminium so will be more than enough for the job, with an EN8 hardened steel plate.

Hope that helps clarify things a bit further.

 

[oldcarman]

@zedonist , I appreciate what you are doing and the information you're passing along is right on. My friend has been drag racing an aluminium clutch in a 500+HP 55 chev for years and has occasionally changed the steel disc but the torture the aluminium has lived through is proof that they are plenty strong enough. Let's keep on track here and get on with the project. We all, I'm sure know turbo, S/C, more CC's etc will give results. I for one like your approach, let's see what can be accomplished for a smaller amount of outlay. Here, they'd be on the pull that little 4 banger and drop in a v8 of whatever brand you favour. I have those, now I want to see the other side of the fence. Just my thoughts, JIM

 

[zedonist]

Thanks Jim you echo my sentiment in this project, I love the big engine projects and the super charge projects, it hits my sweet spot of interest in cars. That said this project is looking at the other side of modification and looking at enhancing rather than transforming.

It does not mean I won't add a DASC at some point as I am always looking on ebay

 

[oldcarman]

Thanks Jim you echo my sentiment in this project, I love the big engine projects and the super charge projects, it hits my sweet spot of interest in cars. That said this project is looking at the other side of modification and looking at enhancing rather than transforming.

It does not mean I won't add a DASC at some point as I am always looking on ebay

Isn't everyone looking for one?? I would if I found one I could afford. lol

 

[hard top]

I am just throwing one in here, how about L80 22% Chrome?

 

[Brian H]

Great thread and great read, thanks to all involved, every day is a school day

 

[zedonist]

I am just throwing one in here, how about L80 22% Chrome?

Duplex stainless, mainly sourced in seamless tube, going to be expensive, the preferred steel would be EN24 in billet form, make a great replacement against grey cast iron flywheels, but not light enough, for what I'm doing and would weigh the same as the current steel one I have which is probably EN24.

 

[TaffZee]

I was not refering to the pressure plate (as this would need to be high grade steel as an alloy would wear far to quickly) I was refering to the other moving parts of the flywheel, one of which was springs built into the flywheel, these springs are continuosly undergoing movement and pressure as these little springs drive the car and may wear the alloy where they come into contact with the flywheel. Although used widely on performance cars, these alloy flywheels generally are of the single mass type flywheel where no moving parts exist.

 

[Lee]

Another cheap option to consider again is the diff. I have a friend who races in the BMW Kumho series and have learnt from him that the majority of the BMW diffs are cross compatible, for example he runs a 1.8 diff on his 2.8 for the tight twisty tracks. Ok his top end has dropped from 140mph to 110mph but the rate he gets there is beyond the reach of the M3's on track. If you jump on my BMW buy n sell page on facebook they often change hands alot for less then £100.

Lee

 

[zedonist]

TaffZee, there are no moving parts in the fly wheel, in replacing the DMF with a solid flywheel, for dampening it uses a sprung clutch plate, below is a picture of the Valeo Steel fly wheel that is being used as the template

 

[zedonist]

The aluminium one will be an exact representation of the picture above.

 

[zedonist]

Another cheap option to consider again is the diff. I have a friend who races in the BMW Kumho series and have learnt from him that the majority of the BMW diffs are cross compatible, for example he runs a 1.8 diff on his 2.8 for the tight twisty tracks. Ok his top end has dropped from 140mph to 110mph but the rate he gets there is beyond the reach of the M3's on track. If you jump on my BMW buy n sell page on facebook they often change hands alot for less then £100.

Lee

Hi Lee,

I agree with you, the trouble is that the duffs came in different sizes and the M44 uses what is called a small case diff, where as all other Z3 use the medium case diff, which was used on all other E36 and others.

The only diff therefore that will provide the gearing you suggest is from the E30, and these are rare, highly coveted and cost more than £100, ive been looking for a while. Other wise I will need to change drive shafts etc to make a medium case one fit.

The other down side on using the E30 one is that first gear becomes pretty useless, so not so good for a road driver, with the fly wheel change I only expect to have to keep the revs up.

 

[hard top]

Duplex stainless, mainly sourced in seamless tube, going to be expensive, the preferred steel would be EN24 in billet form, make a great replacement against grey cast iron flywheels, but not light enough, for what I'm doing and would weigh the same as the current steel one I have which is probably EN24.

True, I have not seen it often in bar stock form and we use it in tubular form for sour gas/oil wells.
A while back I could have got you a slice of incoloy 825 or duplex 995 for nothing
But it would probably still be to heavy and incoloy is a SOB to machine.

 

[EnthuZiaZT]

Well Zedonist, it depends on how you lighten a flywheel. One method would be to remove some material from the back of the plate on a lathe. Another would be to drill holes in it. Both methods work well and by using both it would be possible to remove quite a bit of weight from the flywheel without compromising the strength to much. As for turbo charging, adding a turbo underneath the car would be quite easy and cheap if you bought a secondhand turbo and some aluminium pipe to duct the in and out air flow. Of course this puts the turbo in a vulnerable place, but with a bit of thought, it could be easily protected.
Gearing changes are also quite straight forward by changing the Diff ratio.Unfortunately its not the ratio of the diff that is at fault with these cars the gear ratios in the gearbox are in my opinion to close together, for example i'll bet the guy in the 2.8 goes through the gears really quickly to get up to speed. What is needed is gear ratios that allow you to hang on to 3rd and 4th a little longer to make uses of the extra power of the engine. Put a diff from a 2.2l in it and see if that helps.

Mike

 

[oldcarman]

Mike, your views are accurate and each vehicle making changes such as these require a lot of thought to what the exact end use will be. Some need rear gear some need tranny ratios but ultimately you want to be able to hit and keep that motor and mechanics behind it in it's optimal range for what you're doing. I for one will be waiting for Rich's posting results. JIM

 

[zedonist]

Hi Mike, valued contribution, but Jim is correct in this instance, I'm not looking to radically alter the mechanics of the car, so for me a Turbo is out of the question, and in reality it's not that easy it will require a fair amount of fabrication to the inlet and out let manifolds it will require some way of controlling boost and venting over boost, the boost cannot be too high due to existing compression ratios, and I would not like to add pressure to internals I have not reviewed, at which point I would reduce compression anyway, then you have control heat, which means an inter cooler and control the fuel air ratio which means mapping or a new ECU and perhaps an improved fuel pump and regulator, so perhaps not so easy or cheap.

The Diff I have already explained, to get one to fit direct is an E30 and like hens teeth or its a complete rear axle transplant, which is not cheap again.

I also wish that lightening the flywheel was that easy too but you have to remember safety, at 5000rpm this will go through the car like a buzz saw through butter if it let go. Putting holes in one adds stress areas, and not maintaining at least 10mm wall thickness at thinnest point makes it weak, hence why my steel one cannot be done.

I have done a fair amount of research on this, and while the turbo or DASC sounds tempting, if I were to take the engine apart I would just have if taken out to 2.1 litres and keep normally aspirated, with fast road cams, and everything lightened and balanced etc, it's not a FI car and as such I think it would lose its driving character, well for me anyway.

Hopefully this thread will provide information for other M44 owners when clutch change time comes as to an alternative that may enhance the driving experience, if it does not work, then nothing lost as I get a new clutch and my selector seal changed as already planned.