Clutch kits with 350 Nm torque capacity?

[weber]

I finally got my electric NA6 registered so I can test drive it and I find that the existing clutch has no hope of coping with the 350 Nm of my electric motor. I understand this would be the torque expected from a forced induction engine producing about 220 kW. But don't get too excited -- with the electric, that torque tapers off beyond about 3000 rpm.

I've found it very difficult to get torque capacity figures from dealers or manufacturers, and when I do it is often conflicting.

I can't easily upgrade to an NA8 flywheel as the flywheel was made specially to couple to the electric motor's keyed shaft, and unfortunately we made it for a 200 mm clutch.

Can anyone recommend an inexpensive NA6 clutch kit that they _know_ can cope with 350 Nm?

Smooth engagement is not essential as the electric doesn't stall but gives nearly full torque down to zero rpm. I don't mind some extra pedal effort, but it would be nice if my wife can still drive it. Thanks.

[davekmoore]

How will your gearbox, diff and tyres get on with that torque?

[Locutus]

Give NPC a call and ask them to put together a custom clutch.

[zossy1]

No need for a custom clutch.

You could use an ACT 4-puck or 6-puck clutch, or if you don't want such a heavy pedal, go for a Tilton or OS Giken twin plate.

I too am a little concerned about putting that much torque through the stock drivetrain though!

[16bit]

http://flyinmiata.com/index.php?deptid= ... r=08-19010

http://flyinmiata.com/index.php?deptid= ... r=08-19015

http://949racing.com/SuperMiata-Sport-C ... ta-B6.aspx

all of these are relatively in expensive and rated higher than 350nm. the 949 one would need the ceramic option.

[davekmoore]

...... and one of them mentions that it'll be stronger than the rest of your drivetrain. Perhaps you need a couple of space saver wheels on the back?

[NitroDann]

If you want a no BS solution that is guaranteed to work and also feels really nice(I can confirm), use the 949 twindisk, rated at 400 and the ceramic version rated at 550ftlb.

Its 1k though.

Google '949 twindisk'.

Dann

[weber]

Thanks so much for all your suggestions guys. The single most useful piece of information was the link to the 949 Sports clutch. http://949racing.com/SuperMiata-Sport-Clutch-Miata-B6.aspx Thanks 16bit. This is because it confirms that a clutch kit with about 50% more clamping force and ceramic pucks will do the job. I'd seen the figures on the ACT website but I'd been given much lower torque figures for what seemed to be comparable products by a guy at Exedy. So I didn't know which to believe. Thanks zossy1 for confirming the ACT figures. I now wonder whether the Exedy guy was giving me ft-lb figures but calling them Nm. I had also seen the Flyin' Miata kits, but they are 225 mm clutches, not the 200 mm I need. But thanks davekmoore, for pointing out what they imply about the strength of the transmission, namely that it breaks somewhere between 430 and 480 Nm (318 and 353 ft-lb). At Richard Larsen's suggestion we replaced our NA6 diff with the tall Aussie NB diff (3.636:1) which we understand to be stronger. We don't expect to have much use for first gear.

Thanks NitroDann, but $1k is OOTQ. And thanks Locutus, I hadn't found NPC in my searches.

I now have a Brisbane supplier Direct Clutch Srvices offering me a kit similar to the 949 Sports (+50% force, ceramic) for $575. Anyone know what the typical additional costs are for importing?

Now I'm having trouble deciding whether to go for a solid hub or a sprung hub. I'm getting some problems with torque oscillations even on gentle takeoffs (clutch fully engaged the whole time) and my motor controller guru tells me that a solid hub would be better from a control point of view. Springiness in the drivetrain just confuses the electronics. But I worry about the shock loads on the gearbox when changing gears. I probably don't need to change gears, but I want to change gears, on the fly, quickly and under hard accelleration. After all, it is a sports car. Can I risk solid?

[mazmad]

No additional costs other than freight, which could be exxy. I recently bought in a couple of flywheels, so probably larger and heavier, can dig out the freight cost of that if it helps.

949 will quote you on the freight cost too btw.

[davekmoore]

A Tesla makes do with one gear. With all your torque could you do the same?

[zoomzoom]

I can recommend the Direct Clutch product first hand. I have a NA6 clutch and flywheel in my track car for reduced mass and I had Direct Clutch custom build a unit with increased clamp load and a sold centre like the one pictured in the lower image. My car is putting down about 370Nm/235KW and so far seems to be holding well after around 12 months of trackdays.

Cheers,

Tim

[and1]

The reason the 949 Racing twin disk is more pricey is because it comes with the flywheel which is mated to this particular clutch.

I can't wait for mine to arrive!!

[weber]

I can recommend the Direct Clutch product first hand. I have a NA6 clutch and flywheel in my track car for reduced mass and I had Direct Clutch custom build a unit with increased clamp load and a solid centre like the one pictured in the lower image. My car is putting down about 370Nm/235KW and so far seems to be holding well after around 12 months of trackdays.

That's great to know, Tim. Thanks.

This page (and others)
http://www.turbomagazine.com/tech/0407tur_clutch_tech_basics/
make it clear that the spline damage that can occur with solid centre clutches is primarily due to the torque pulsations that are an unavoidable result of using an internal combustion engine -- one per explosion. Not an issue with electric motors.

So I'm going with the solid centre in the hope of minimising control issues caused by drivetrain windup.

[elitee]

Your looking at about $400 delivered for the sports clutch with ceramic plate I am about to purchase one and have already priced it up

Sent from my HTC_PN071 using Tapatalk

[weber]

Your looking at about $400 delivered for the sports clutch with ceramic plate I am about to purchase one and have already priced it up

Thanks elitee. So that's this device https://949racing.com/SuperMiata-Sport-Clutch-Miata-B6.aspx and you're in Australia and that's Australian dollars?