tervanun

Hello all,

I'm new here and trying to get an answer to:

Which year(s) 13b's will bolt up to a miata transmission?

I have a 94 miata transmission that I want to mate to a soon arriving
13b NA, BUT, I'm not sure which years make this swap possible.

I already tried an FD transmission and it does not match up...

So before I get another incorrect tranny, can someone please point me in the correct direction

THANKS!

gracer7-rx7

iTrader: (16)

What didn't the FD trans match up against?

I don't think any bolt right up. I think the bell housings are different. Maybe also the location of the input shaft.

I have read of people installing the guts of the Miata trans inside of a rotary trans.

hioctane-dtc

iTrader: (1)

You need to mod the input shaft in order to make it fit.

Miata Input Shaft Modification

Most people use the gears out of miata tranny like gracer7 said.

krgoodwin

The miata bellhousing, input shaft and tailshaft housings are different than the N/A RX-7 trannies. A lot of guys just swap the gears into an RX-7 Tranny instead of reusing the whole thing.

In my Miata I added an RX-7 bellhousing to my Miata tranny so a 13b would work with the stock tranny in my car. The input shaft still needs to be machined as it it too long.

If you are using an rx-7 chassis your best bet would be to swap the Miata internals into the RX-7 case.

RBURR

this always confused me.

vampirebeats

iTrader: (9)

Are the miata gears more robust than the S4 N/A gears?
I feel like it would be a waste of time to swap my auto with a N/A S5 manual box.

bass2theplace

i dont think the miata boxs are tougher than a s/4 box, especially not a turbo box

tervanun

Thanks for the replies guys, got it figured out now.

Its not going into an Rx7 chassis, its going into a 240Z....
I know the miata transmission is almost 20lbs lighter than the FD trans,
So I'm guessing its still also a good amount lighter than the FC.....

So I'm gonna use the miata if I can.

tervanun

Anyone know the weight of that NA 13b transmission?

tervanun

And a place to get at least the front housing so I can do this swap?

RXSpeed16

iTrader: (41)

Somewhere about 80 lb. I think.

Non-turbo transmissions don't have a detachable bell housing. This is why people swap the miata gears into the rx7 case. Since you'll need the miata trans open to remove the input shaft, its just easier to swap the internals.

RotaryEvolution

iTrader: (30)

basing a decision based on the weight of a transmission is generally a bad choice to start with. if i had an FD, FC n/a and a miata box i can tell you which one i would almost always pick.

Brian Keene

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