Hard to imagine a better Miata clutch!
That is the custom clutch version is it not?
I talked to custom clutch about a dual clutch that I thought was the 949 clutch...and mixing that with a T5 6 months ago...
The head of oddball clutches said it was totally doable.


Getting it to fit a BMW doesn't seem like a quantum leap, but who knows.
I can look up the email of their head wizard of weird clutches if you want?

What is the BMW clutch diameter KMiata?

It's not a custom clutch. It's a comp clutch. And it has to do with the spacing not the size. You want a 7.25" because of the smaller MOI.

Got bored and made some graphs. Figured out that the E36 5 speed and the Miata 5 speed share some pretty similar ratios, the E36 being much lower. Gears 3-5 line up very well when comparing the MIata 5 speed with 4.1 rearend and the E36 with the new 3.3 rearend with the E36 having slightly lower 1 and 2 gearing.

https://cimg6.ibsrv.net/gimg/www.mia...9347512391.jpg

The E46 6 speed is basically the 5 speed plus an overdrive gear. Mapping the 6 speed with the same 3.3 compared to the Miata 6 speed with 3.9 (my current config) makes some interesting results. E46 1-5 has the same spread as Miata 1-6 with a super nice cruising gear on top of that (3000rpm at 80mph anybody?).

https://cimg6.ibsrv.net/gimg/www.mia...fee5d5a818.jpg

I'm still curious about why it's specified non-M e46 6speed trans. Ive been able to find more m3 transmissions than 330i/z4 unless they are all just the same. Everything is attractive about these solutions, I'm still in the honeymoon phase

Nice graphs Dane, thanks for posting!

240mm clutch disc.

Non-M trans is specified for two reasons. The first is the 330i trans is less than half the cost used, and is still very strong.

However, the main reason is the rear mount style. BMWs use two rear isolators below the mounts. This works perfectly with the shorter 5 speed trans, but the 6 speed is 4" longer, and as the tunnel narrows, we lose all ability to clear a 3" exhaust if we stick with the factory isolators. The M3 trans has the prongs on the back of the trans cast into the casing, just like the 5 speed. But the 330i trans conveniently has this bracket on the back that can be unbolted:
https://mail.google.com/mail/u/0/?ui...&sz=w1366-h638

Since it can be removed, we have built a 6 speed-specific mount that replaces the OEM bracket and uses a GM style rear isolator, just like a T56. It makes everything fit much nicer and allows for easy 3" exhaust clearance. I'll post pictures of both the 5 and 6 speed mounts once I have final samples that look beautiful. They are being fixtured right now.

Also, on a somewhat unrelated note. This Getrag diff is fantastic. For those who don't know, its a clutch-type diff vs. the gear-type Torsen.

I drove the test car for two hours straight at Gingerman yesterday evening, and I was pleasantly surprised by how much better the rear end of the car hooked up compared to a Torsen.

Considering the diff cost me $124, its an upgrade I'd like to see a lot more customers choose. They are dime a dozen. My used parts guy offered me three of the 3.42 LSDs for $300 delivered!

Sure, you need to buy the parts to make it all work, but afterwards you have some really nice benefits. Dirt cheap diff options, good ratio selection, upgraded axles, optional upgraded hubs, near-solid diff mounts, and a super easy PPF delete. I certainly would choose this over a 3.63 or 3.3 in the Miata carrier, specifically if you're paying someone to swap the gears. if you go with our trans upgrade, you need a custom driveshaft anyway, plus the front diff mount to delete the PPF, so this is a perfect combo.

^^ that's exactly why i'm holding off on changing gear ratios on my car. When I am ready to go, I will spend the money on the getrag.

Super thanks for the clarification! The search for a 330i trans continues!

Pilot might be interesting, good point. Figured it was the same size, and that the length was already right. The hydraulic tob is much nicer feeling that the miata setup though, and you would probably just buy the whatever tilton 52mm (or whatever size you need for the 949 pressure plate fingers) one that fit the BMW lever.

You just send the flexplate and some input shaft measurements to quartermaster and $800 later you have a button flywheel and twin disk clutch that fits your setup, and a hydro TOB that doesnt that you can ebay for $200.

Dumb question: what's the difference between a hydraulic TOB and a concentric slave cylinder like on the C5 Corvette? Just that the bearing on the hydraulic version is attached to the hydraulics and not a separate part?

How much do we bribe you guys for a PPF delete "kit," retaining Miata trans?

Same thing, different name. I don't think I've ever seen a concentric slave cylinder without the bearing built in.

They are the same, but different markets call them differently. Production cars generally refer to them as slave cylinders, and motorsports generally refer to them as hydraulic release bearings.

Haha. We could easily do it, but I'm curious to hear why you want it.

PPFs are gross and we could get away with less aggro motor/diff mounts while still having less driveline slop.

Less weight. More room for exhaust. Less things on car.

Bonus points for giving multiple mounting points for use with V8R setback engine mounts.

You know... since you guys are already going to be making mount kits for Miata diffs. :)

is there something specific about v8 rails and trans mounts? I have FM rails and really would like to avoid re-drilling the floor if holes aren't aligned. Though I'll do what I have to do run a BAUS trans setup. Just kinda bummed to add more holes.

But adding holes is weight reduction!

If you go with a 5 speed, no need to change a thing, just keep your existing frame rails. Only the 6 speed rear mount ties directly into the frame rails due to the added length, and then you'll need our specific ones with the mounting pads welded on.

I can't find the original picture I saw. But does the 5 speed mount bolt to the trans tunnel walls?

Correct. It's simple, light, and works great. I'll be going with a little 5 speed in my blue car eventually.

Hmmm. Did you pull that picture or am I going crazy.