So read a thread in the archive about someone swaping their transmission for a miatas. This was an NA though. I have a T2. I drove my friends miata last week and I liked the ratios. It accelarated quite nicely despite the weak engine. The only thing I didnt like was 5th gear felt really short and the engine was high reving at barely 70. I was wondering if anyone has swapped a T2 tranny for a miatas. Would that be a bad move? Is it even Possible? What are your thoughts?

 

I also read this thread and it's been eating away at me for a couple of weeks now. I have an NA S5 and am pretty sure I'm going to do this. My excuse to do it is that my 2nd syncro is out and I already have some transmission problems. The thing is, I need to find a miata transmission first. Next, I need to find a mechanic that believes in the spirit of the whole swap in the first place.

 

I know its tempting. I dont know if its good for me though sice im T2. I need to get more info. I think you have to get something machined but the miata gears fit in your cars gearbox aparently.

 

It d be cool to say u did it, but 1st and 5th gear would bee pretty much useless. My friend has a s/c miata and it can't find traction in first for anything, now that I think of it; most of second either. Its under 230whp btw

 

i saw this earlier.. and then i was just lookin around and found this post https://www.rx7club.com/2nd-gen-archive-72/miata-transmission-into-na-fc-results-524587/
pretty sure thats what you want right?

 

Whats an s/c miata? Is there something wrong with the transmission or the clutch? Why do you say first and second would be useless to me?

 

Ya this is the one I read. This is for an NA though. Im wondering about my T2.

 

S/C = Super Charged
5th = Fifth

There is nothing wrong with the transmission... when mated to an engine w/ no power (stock miata, n/a 13b etc...) Power + short gears = dorifto action!

First will be useless because anything more abrubt than a slow roll onto the throttle will break loose all but the stickiest tires.

Fifth will be useless because you'll be at like 4 grand doing 70 on the freeway, which is: 1) Annoying 2) Not fuel effiencient 3) Limits your top end (theoretically anyways).

I'm not sure what the purpose of this car is, but for anything other than auto-x such a swap has little merit. Also, I'm not sure what kind of power you're making (or plan to make) and how that would factor into the equation, the highest hp miata (non swapped) i've seen was low 300's not sure what the tranny can handle.

 

Ok guys given that I have actually attempted this and failed it is not a direct swap.

I was actually attempting to put an rx7 gear set in a maita case because of the taller gear and simply because the miata tranny took a **** on me.

You will have to take the tail housing off which is not that hard, but the main housing is. These trannies do not have bellhousings per se, most of the gear box is in the front housing and you have to beat the **** out of the input shaft with a sledgehammer to get the **** loose, and unless you have a press good luck getting that input shaft bearing in once you try to put the gearset in the proper housing.

All in all especially for your t2 this swap is not worth it at all, and for an FC it would be great for the track for the shorter ratios but 5th would suck *****. Basically if you are really nuts, have access to a machine shop, autocross your NA, swap all gears but 5th. Otherwise so not worth it.

 

You realize the Turbo transmission and the non-turbo/miata transmissions are completly differently. Like not even close. No parts are interchangeable.

You would have to swap in the entire miata transmission or source a non-turbo trany for some kind of hybrid. Then have a custom driveshaft and possibly trany mount made.

 

not if he got an NA tranny and swapped the gear sets. Then he would still have to get an adapter from Mazdatrix to run the NA driveshaft. Then you have a weaker tranny for your turbo car.

Altogether for your application it is a bad idea.

 

Agreed. In all reality the NA/Miata transmission family are too small (weak) for just about any 2nd gen RX-7 for anything other than going to work and back...much less a turbo car.

Hell the miata's blow them up constantly on the track.

 

Mine held tough at 200whp (via a Mustang dyno) for over 15k miles. When I sold the 'yata there was nothing at all wrong with the tranny or shifting. It was as smooth as ever.

My Miata was an NB (2001) though.

 

With the mazda transmissions it is not usually power that blows them up racing. It is downshifting. 3rd gear blows up when you downshift and put a lot of load on it engine braking then getting back on the gas.

Happens to the turbo ones too.

 

Ya. Thats what I noticed about my friends miata. 4k at 70mph. It sucked.

 

Ya my 3rd gear grinds sometimes on the down shift unless i rev-match or double clutch.

 

This is good info. Thanks guys. It sounds like a lot of work and it sounds expensive seeing as how I dont have many tools. It sounded simpler in the thread I read.

 

so I can keep 5th gear and use the rest? Is it possible to keep 1st also? Guess that would make for funny ratios. Lol

 

2001 tranny? 200hp is about what the T2 comes with. I wonder how much power they can handle. I read in another thread that the RX8 tranny is a moded version of the miata transmission.

 

so Im guessing that an FD transmission is out of the question. I feel that someone would have said "just swap it for an FD tranny" by now. Lol

 

Actually, the swap to RX-8 6 speeds (and the 5 spd, but that wasn't sold in RX-8s here, just Europe and Asia) is covered in the FAQs. The RX8 transmission is 4" shorter, so shifter ends up where your radio should be, or you have to relo the engine further back in the chassis. RX-8 final drive is actually shorter than the na FC, so mileage suffers, you basically just end up adding an extra ratio between 3rd and 4th in the FC.

As far as Miata (NB) transmissions go - a guy locally ran his 250hp sc NB for several years for lots of autocrossing and time attack track events, besides being his dd. No problems with that tranmission. Just one example, but they certainly can stand up.

 

Post count +1!!

 

Actually, I think I'm going to try it out anyway. I won't know personally until I try it.

Inspiration: http://www.mazdatrix.com/faq/miatainputshaft.htm

 

the 6 speed transmission is an aisin warner unit, and there is a version in the 99+ miata's, but it shares nothing at all with the 5 speeds.

the 2003-2008 rx8 6 speed is similar to the 99-05 miata 6 speed, its a similar design and case, but the rx8 has BEEFY shafts and gears and such.

http://en.wikipedia.org/wiki/List_of..._transmissions

the 2009 rx8 uses a mazda 6 speed, which is also found in the 2006+ miatas. this unit looks to be based off of the transmission mazda builds for the ford ranger/B-trucks

 

I knew someone was gonna laugh.