On my T5z, Length from input shaft tip to the T5 flange face is 7.145. :dunno:

If your dims are right, it all makes sense to me.

I'd rough cut the flange outer profile, weld it to your cut down donor miata bellhousing, then put it in your mill on your dowel locating fixture and surface mill it flat/parallel to the engine side flange to your 7.189+.410 dim. While its there, you mill the locating hole for the bearing housing and drill/tap the mounting bolts, using your fixture.

Or my models are way off, which is why the first thing I would do is redigitize it all.

Weird. I was going off this spec sheet: http://www.rsgear.com/TCase/TREMEC/T5.pdf

I'll measure again when I get home.

My fixture is going to use the bearing housing as the locating dowel for the tranmission side flange. So I planned on cutting out the bearing cover hole and mounting bolt holes with waterjet, then center the plate on the miata bellhousing with the fixture.

I'm not sure I am competent enough on a mill to mill the bearing cover hole myself.

here is a rough drawing of the fixture we plan on building.

Attachment 231073

You could use the longer 94+ input shaft too you know. That plus the camaro tail housing might equal no need to shifter extendo. And those camaro tail housings should be easy to get from any hot rod guy that put an s10 tail housing onto a camaro tranny.

My model is off, I updated my post to be clearer

It wouldn't put it close enough. I think it would actually put it in a really akward position, that would be hard to move back the correct amount.

Well your 7.145 number is a lot closer to my 7.189 I got off the interwebs.

The only thing I haven't confirmed is if the T5 input shaft should go in the same place that the miata input shaft goes. I need to compare the 2 shafts and make sure it doesn't need to be adjusted one way or another.

You're going to be constrained by the pilot bearing more than anything.

Should the input shaft go in as far as possible? I still need to fit a pair of twin discs on the input shaft too.

I've also started conversations with PTT (Power Train Technology) about a clutch disc for my 949 twin disc. Don't really want to bother emilio with a custom disc request, so I'm going to try and work with them.

When I replaced my organic discs they measured in at .308". They were riveted on organic surfaces.

The PTT discs are .250" thick, and have bonded organic surfaces. Theoretically they should be able to wear longer. I will be pulling my twin disc out eventually and measuring how much I was able to wear the discs over a year of use.

I have a call into competition clutch (makers of my 949 twin disc) to ask them about how thin you can wear the plates, before you will have a reduced clamping force. If the response is thin enough then I will go ahead and order some PTT discs for testing...I hope they have a decent return policy if I can't get them to fit.

The T5 has a very long splined area, so if I can get the input shaft in far enough then there is plenty of room for a lot of spline engagement.

What type of clutch is it? Depending on how the housing of the clutch is (part that holds the floater discs and pressure plate, and bolts to flywheel), it could be surface ground to match the preload with the new smaller discs. I'm going through the same thing right now, but opposite. I have a metallic triple disc 5.5" quarter master and the discs are 0.105", and the organic are 0.180" I think, so I'm trying to go to thicker discs. So I was thinking either going down to a twin disc and surface grinding the housing down, or surface grinding the floater plates down to keep it a triple disc. Usually the housing is one of the cheaper parts, so you could buy a spare and grind that one down.

For example, this is my housing: Quarter Master® V-Drive or Pro Series; Clutch Housing (5.5", 3-Disc)

For

Its a 949 twin disc. I assume that it could be ground down if needed. But I'm wondering if it could just handle it as is.

Just spoke with competition clutch. Their disks are spec'd at .250" new. Which matches those of PTT perfectly. They are spec'd for replacement at .235", which isn't a whole lot of wear.

Going to do some measuring tonight and see what I can come up with. This might work. Unless PTT has been tested by someone else.

I'm kind of worried, because if they fit so easily I'm surprised emilio doesn't supply them with the 949 twin disc, which makes me think there is something wrong with them...

Played with shifter ideas today. Drew a very technical drawing of my plans for an adapter.

Attachment 231072

This will lead out to a shifter mounted above the U-joint.

Kind of like how this video does it. But without the offset and angle shit needed.

You just rattled off a bunch of stuff and I have no idea what is what. On my 949 twin disc, I just bought ceramics to replace the organics since I didn't want to wait for 949 to get the new batch of organics. The organics I took out are the same thickness as the ceramics I'm going to put back in: 250". Now I didn't mic the discs but you can tell they are the same thickness. So yeah, .235" and they are no good for the organics. At the thickness, my pressure plate sits flat against the flywheel without ever tightening bolts.

So bonded organics at .250" thick sounds pretty much useless to me. I called comp clutch and they said they didn't have organics for this clutch.

comp clutch doesn't. Which is why I've been in contact with PTT. They spec their organic discs at .250", which is the same as what Comp lists their ceramics as. Like I said. The organics I installed were .308 so if I could get PTT to make some that thick I would do it for sure.

I don't know what kind of abuse you have in mind for your clutch but at 4 years, 15k street miles, and ~35 autox's, my organics were done. This poor life span might be enough for me to swear off the organics if I get any kind of acceptable driveability from the ceramics. I loathe taking out this transmission.

4 years would be plenty. I can do a clutch in a Saturday morning and still have time for stuff in the afternoon. Biggest issue is the PTT discs are $286. And can't be resurfaced. Ill be pulling my organics soon after a year to measure wear and see how things are doing.

I may just wait for Emilio to release new organics, then ask very nicely if his supplier could make a set for the T5.