Miata/RX8 engine and bellhousing question

My Google foo is weak today.

Is the bellhousing pattern on the BP, B6, MZR and Rotary all the same?

What is the difference in the transmission in a RX-8 and a NC?

Thanks

I'm 99% sure on all of the following:

The rotaries are all the same, but they're not compatible with any piston engines and the bell housings are not removable. The B6 and BP are interchangeable, but the MZR is different. The early RX8 transmissions and the NB/early NC transmissions shared a common design for the internals and likewise, the later RX8 and NC transmissions shared a common design, but in different cases (no idea on the gearing differences).

to clarify, 3 different bellhousings: B6/BP, Rotary, MZR

3 different guts but the timing of the guts and the bellhousings are not the same. Correct?

MZR and Ecoboost are the same, which opens up some interesting possibilities.

There's actually an NA/NB split in the bellhousing design, but it's only one bolt for the starter. Otherwise interchangeable.

The guts have more in common than you might think, but given the bellhousing incompatibility it's irrelevant.

I was hoping for the Ecoboost and the RX-8 bellhousing to be interchangable, that makes things REALLY interesting given the # of blown engine RX8s around

I would have sworn the bellhousing on the RX-8 transmissions came off. Now I have to go look at one, though I am guessing that betting against Keith is a losing proposition.

If you want that Ecoboost in an RX-8, remember that the NC Miata and the RX-8 are related under the skin. Front subframes interchange, for example. The MZR bolts in, which means it's quite likely the Ecoboost does as well. The high pressure fuel pump overhanging the bellhousing may be a packaging challenge.

NC Miata bellhousing is not removable.

It looks removable (RX8).

JamesMcD wrote: It looks removable (RX8).

it is... kinda.... the front seam is one to the front of the gears, not just a bell housing

For example... here is an RX8 trans, but it is now fitted with the bellsection from Nissan's S15

As to gear ratios....

S15 6 spd 3.626 2.200 1.541 1.213 1.000 0.767

NISMO 2.907 1.989 1.537 1.218 1.000 0.862

RX8 6 spd 3.760 2.269 1.645 1.187 1.000 0.843

Miata 6-spd 99- 3.760 2.269 1.645 1.257 1.000 0.843

SXE10 6 sp 3.874 2.175 1.484 1.223 1.000 0.869

TRD(33030-SE100) 3.106 2.175 1.585 1.223 1.000 0.869

Oh.. the FRS transmission... is a further developed version of the AZ6 -

FRS - First Gear Ratio 3.626, Second Gear Ratio 2.188, Third Gear Ratio 1.541, Fourth Gear Ratio 1.213, Fifth Gear Ratio 1.000, Sixth Gear Ratio 0.767

All but one used from the S15 version.....

Additionally, the S15 6th gear has been fitted into the Toyota transmission (known as J160)

here is the Toyota version with the original bell housing, and the LEEN adapter which closed off the bellhousing and accepted a T50 bell

JamesMcD wrote: It looks removable (RX8).

NC Miata is not. BTW, that's an Ecoboost in the background.

The Toyota version fully modified to fit into an AE86...

I am seeing RX8 in the challenge money range. I am seeing NCs in the $5k~$6k range that would be good swap candidates.

The issue is money and seats. I like the RX8 seating for my boys, and the Ecoboost, but the the costs start going way up when I have to do a front cross member, and transmission.

Grrrrrr.

You want access to a wrecked NC, not a driver. I'll bet most yards would be happy to get rid of a front subframe, and there's no demand for the trans.

Who would have thought it might cost money to change to a totally different engine type?

RX8driver wrote: I'm 99% sure on all of the following: The rotaries are all the same, but they're not compatible with any piston engines and the bell housings are not removable. The B6 and BP are interchangeable, but the MZR is different. The early RX8 transmissions and the NB/early NC transmissions shared a common design for the internals and likewise, the later RX8 and NC transmissions shared a common design, but in different cases (no idea on the gearing differences).

Miata and RX-8 input and output diameters are different.

Rotaries are mostly the same everywhere 1974 and newer, although FD and Cosmo got a little oddball. Especially automatic models. Couldn't tell you on RX-8 but RX-8 transmissions bolt up to '74-up engines so it can't be too far off.

Keith Tanner wrote: Who would have thought it might cost money to change to a totally different engine type?

So how much is a Miata LS conversion Keith? I should call you and ask lots of questions right now.

Might be worth it. My front subframe, trans and blown engine for your front subframe and trans. I get rid of what I don't need want for something they don't need.

Might work.

You might be able to find an NC Miata owner who really wants a rotary swap Or someone doing a V8 swap, they will have parts you don't need.

Looks like we actually have a subframe left over from a swap. $125 plus shipping - although the latter might get spendy as they're bulky. No transmissions alas.

Keith Tanner wrote: You might be able to find an NC Miata owner who really wants a rotary swap Or someone doing a V8 swap, they will have parts you don't need. Looks like we actually have a subframe left over from a swap. $125 plus shipping - although the latter might get spendy as they're bulky. No transmissions alas.

Greyhound should be able to ship it for a relatively reasonable price, if you guys are willing to drop it off at a Greyhound station for the OP.

Keith Tanner wrote: Looks like we actually have a subframe left over from a swap. $125 plus shipping - although the latter might get spendy as they're bulky. No transmissions alas.

Colorado to DC? It would cheaper to build one out of titanium I think than ship it. I am planning, don't worry, I know when it comes suspension time I will be giving you guys a call.

I don't want to thread jack, but does anybody know if there's a mid-shift style kit for that NC Miata trans? I've never seen one, but if anybody would know where such a thing might be hiding, it's you guys.

mid shift style kit?

Stefan (Not Bruce) wrote:

Keith Tanner wrote: You might be able to find an NC Miata owner who really wants a rotary swap Or someone doing a V8 swap, they will have parts you don't need. Looks like we actually have a subframe left over from a swap. $125 plus shipping - although the latter might get spendy as they're bulky. No transmissions alas.

Greyhound should be able to ship it for a relatively reasonable price, if you guys are willing to drop it off at a Greyhound station for the OP.

And if the OP is willing to hang around at a Greyhound station.

Flight Service wrote: mid shift style kit?

A lot of manuals, typically Tremecs, can have different shifter locations. Many had the shifter in the tail, but the shifter could also be moved closer to the center using a special kit. It's common to use a mid shift kit on T5s and T56s when swapping into another vehicle if the stock shifter location won't work.

Sorry for the thread jack.

no biggie, I had no idea the term was Mid-Shift.

I dunno, would make different installations easier but I am willing to bet with the lack of desire for these parts that you would have to fabricate a remote shifter.

but that is purely hypothetical

JamesMcD wrote:

Stefan (Not Bruce) wrote:

Keith Tanner wrote: You might be able to find an NC Miata owner who really wants a rotary swap Or someone doing a V8 swap, they will have parts you don't need. Looks like we actually have a subframe left over from a swap. $125 plus shipping - although the latter might get spendy as they're bulky. No transmissions alas.

Greyhound should be able to ship it for a relatively reasonable price, if you guys are willing to drop it off at a Greyhound station for the OP.

And if the OP is willing to hang around at a Greyhound station.

To further the slight thread jack: I shipped my entire NA soft top (frame and all) from CA to NJ for ~$30 via Greyhound. It got there in three days too.

Greyhound just takes anything these days?!?!?