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bilgladstone

Cdi Sport Clutch...

20 posts in this topic

With crazy power-up mods to the CDI, and for those who tow, it is expected that there will be early clutch wear. In following UK discussions, we've read about upgrade clutches, i.e. Roadster, Brabus and Bonalume.So enquiring as to what more robust options might be available that would fit the CDI, I contacted Denis at S-P-D, smart specialists of solid reputation, and this was his answer:

Smart make only one clutch for diesel models, the engine is virtually same as always on the older model from 200-2006, just a few more horses from 2009. Unlike the petrol variants of the older models where there were 3 clutch types going up to 101 hp, the diesel has only ever had just the one.

Rather a disappointment... unless anyone else knows differently?Bil :senile:

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I maybe wrong but I thought Bonalume used to make a clutch for the CDI with the same power rating but better friction material than the clutch supplied to Smart. Why not write them and see what they can do for you ? Would not a stronger clutch require a matching stronger clutch actuator ? Good luck Bill you "little engine that could". PS. Have you got your reservation for a camp site in the Tofino - Ucluelet area yet? In "Prime time Season" I have seem 300 campers lined up at 6 am trying to get into a site that couldonly hold 100 cars and No Camping signs on every level piece of land out side the park for many miles around.

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Did a Google translation and have now written to Bonalume Italy. Hopefully I won't need one real soon but it's always good to line up parts sources for the future if you intend, as I do, to keep the wee smartie for an extended time. The race clutches for the petrol engines didn't mention anything about different actuators...I am giving it just one more day to hear back from other friends on the Island as to their available dates and then will book Thursday afternoon whether they get back to me or not!Cheers,Bil :sun:

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If the springs are @ the same tension as the regular pressure plate springs, then another, stronger actuator would not be required. On the other hand, the torque rating of the clutch would also be unaltered, so it would not resist remapped torque any better than the OE clutch. Hence I would be curious what the advantage would be. Wear resistance? If so, how would the clutch feel when moving off? The OE clutch is already jerky! Inquiring minds etc.

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For one, I thought the clutches were all interchangeable -- though it would be seemingly unnecessary below 130 Nm at the flywheel. I can't imagine the actuators are different at all.

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Straight from Angelo Bonalume himself:

no for diesel no

regards

Angelo

Il giorno 22/apr/10, alle ore 04:55, Bil Gladstone ha scritto:

> 2005 smart fortwo 0.8L CDI, 89,000km

>

> Is Bonalume racing clutch available for this engine?

>

> Sono le corse Bonalume frizione disponibili per questo motore?

>

> Grazie,

> Bil Gladstone

> British Columbia, Canada

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Mike, by changing the friction material you can get more/less holding power for the same applied force (same spring tension). Depending on the friction material there will be all kinds of tradeoffs - different organic/metallic/ceramic compounds will have different friction/wear/noise/smoothness/dust etc. Hub design will change the properties as well, whether the hub is sprung or not or how stiffly will drastically change how the clutch engages (might be wonky on the smart though because the computer might not be able to deal with it). AFAIK, hub design won't change how much force it takes to depress the clutch, as the clutch acts linearly against the pressure plate springs whereas the springs in the clutch hub are just dampening out torsional vibration...

Edited by booneylander

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Sure, that's a given but: Clamping force increases are the only way to make a significant increase to the torque rating of a clutch. Simple mathematics, like cylinder head bolt torque determining the kg equivalent of force on the head...and as I wrote, stiffer PP springs would require a stronger actuator.But the point is moot: the part is not available.

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Clamping force increases are the only way to make a significant increase to the torque rating of a clutch.

I disagree with this statement.A good read:http://www.motoiq.com/magazine_articles/ar...n-material.aspxHere's a good table, unfortunately the data is Qualitative (1-5 scale) rather than Quantitative (actual Mu). But some good info.

Friction Material Characteristics(Rating 1-5, with 5 being best)Material Type Smoothness Burst Strength Mu Cold Mu Hot Life AbrasivenessOrganic 5 1 5 2-1 2 5Kevlar 5 3 4 2 3 5Semi Metallic 4-2 3-4 4-2 4-3 3-4* 4-2Copper Ceramic 2 5 2 4 2-4* 2Sintered Iron 1 5 2 5 2-5* 1Carbon 5 5 2 5 2-5* 5* The smaller number is street use, the higher number is racing use

The fact that an over-the-counter drop-in clutch for the cdi isn't available doesn't mean we're SOL. Clutches are not rocket science. There are tons of shops that can re-line your clutch, with whatever friction material you want... and probably for less money than a stock replacement... modify the hub? no problem...You just need to know who to talk to to get exactly what you want, and be ready to live with the downtime while they rework your disk.

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Yeah... moot.I also understood that the Bonalume clutch has wider mating surfaces and a lighter flywheel. Both important factors.FYI, a new OEM CDI clutch costs about $550 plus installation.Bil :senile: ...takin' 'er easy.

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I disagree with this statement.

Well the disagreement is likely down to what "significant" means. More grippy (and therefore useless on the road) linings won't make a 110 Nm clutch pack a 150 Nm clutch pack.But...the point is moot!

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:rolleyes:

I gotta say, I'm really surprised that for a couple of car guys, Bil, with all the custom mods you've done, and Mike with your sizeable vintage fleet, that you guys are going to tell me 'I can't buy it over the counter... so... it's impossible'.

F=µN

And the µ can range from 0.35-0.55 for various 'streetable' clutch materials. So a 110Nm clutch could be made into a 170Nm clutch just by changing the lining, and still be streetable...

Anyways, I guess I'm wasting my time, since we've already decided it's moot...

Oh, and the last clutch I had re-lined was in the 80$ ballpark IIRC.

Edited by booneylander

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I'd believe that if I saw it. Every proper racing clutch I've ever seen has uprated pressure plate spring tension. Even OE clutches for the Peugeot 404 had uprated PP springs for the fuel injected version; the linings were the same. The 404 had three: PKSC 12 (12 mkg), PKSC 14 (14 mkg) and PKSC 15 (15 mkg), the latter being for the fuel injected car I have. And yes the pedal effort is higher. There is a good reason they used uprated clamping force and not different fricton linings....And: the point is moot!

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[back from moot court - I'm not that much of a car guy ;) ]

This is interesting; I didn't know you can get a smart clutch relined. You're right in that I was searching for the plug-n-play solution. Is there a core charge when you get a smart clutch replaced, or is it like the smart turbo+actuator+wastegate+exhaust manifold assembly that 95% good stuff just gets turfed when all you need is the actuator? What else besides the lining wears out when you "need a new clutch"?

What about the flywheel? Can it be made lighter?

Bil :senile: .... living' and learnin'

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Bil, are you worried about premature clutch disc wear-out due to the remap? Has the clutch slipped on you?

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Mike, the launch is pretty smooth compared to what I'm reading of others' experience. I have had Eddy digitally micro-tune the drag point twice and next time I visit him I'll likely have him do it again because it does get less crip over time.

I won't say that it slips any more than a conventional standard clutch would, e.g. a bit stuttery taking off on a steep grade.

So I don't need it now, but I can see eventually needing it replaced one day. At this point though, it's basically a thought experiment. Or "bench racing" as I've heard it called.

B :senile:

Edited by bilgladstone

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Bil,Depending on wear of each component:-You will always replace/reline the disk - this is what has the 'wear' material. Often, when you buy a replacement disk from a place like Canadian Tire, they will actually sell you a remanufactured disk anyways, one that has had the friction material replaced and depending on the quality, they will change the springs for the hub as well.-You will often replace the pressure plate assembly - the steel that is in contact with the clutch disk will wear over time, and the clamping springs will get tired and not exert as much force as they do when new. *Usually* the presure plate CAN be re-used, but it's one of those "might as well replace it while we're in here because the cost of the replacement part is nothing compared to the cost of labour to re&re it later, and it's already off the car to get the disk out".-You will often want to re-surface the flywheel. Again, one of those "might as well since we're in here", the metal face on the flywheel wears over time, but there is a ton of meat there, and resurfacing just makes sure you have a clean, smooth, surface to mate to your new clutch disk. The whole system is very similar to brakes. If you imagine the disk as being like brake pads and the presure plate & flywheel as being the rotor. The pads wear their own pattern into the rotor, there's nothing stopping you from just replacing the pads if the rotor is in good shape, but it's nice to have the rotor turned down to be smooth, or replace it altogether.When they re-line your clutch disk, they just remove what's left of the old material, bond/rivet the new material on, and trim it down so that everything is clean and smooth and flat, then balance the disk.In a performance application, you could even take the flywheel to a machinist and have them turn the flywheel down so you can use replaceable friction material on the face, allowing you to have different interfaces (carbon/carbon vs. steel/organic etc). There are a ton of friction materials to choose from, each with their advantages and disadvantages, and there's lots that will have as good or better 'feel' AND clamping power as the stock clutch, but as with anything in life, you have to pay for it (a carbon/carbon clutch setup is in the 2k$+ range). Just like anything else on the car, the OE stuff is the generally the best 'bang for the buck' solution, which doesn't mean the 'best' solution by any stretch of the imagination.Cheers,

Edited by booneylander

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"Clutches are not rocket science. There are tons of shops that can re-line your clutch, with whatever friction material you want... and probably for less money than a stock replacement... modify the hub? no problem..."

I must agree, and as you have stated, once they have opened her up they usually replace what they can and when upgrading that also includes the springs if available. How many people replace only their brake pads on their cars or bikes and swear by the significant improvement (myself included).

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The smart clutch is self-adjusting for wear, unlike most others. So the clamping force of the PP remains virtually constant despite disc, flywheel and PP wear. You might be able to get away with doing the linings only because of that (like re-using disc rotors at least once).But if you have to replace the whole clutch anyway (they do not sell the individual components at any dealer) and you've not experienced slippage up to now, I would skip the relining unless you want an even more grabby clutch action!

Edited by Mike T

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I was at the dealer today and they said they have replaced a 1/2 dozen clutches, one with only 80,000 kms.The clutch cost is around $600 and about 4-5 hrs labour.

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