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!

 

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.

 

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.

 

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.

 

this always confused me.

 

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.

 

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

 

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.

 

Anyone know the weight of that NA 13b transmission?

 

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

 

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.

 

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.

 

subbed

 

I made a video on YouTube. My channel is Shifthappens1992
na Miata tail housing bolts right up to 13b S5 non turbo transmission but you have to remove dynamic dampener for the Miata tail housing to fit.

 

13 yr old thread and OP last log in was july of 2021.