RX7 fd3s transmission in my MX5
 

The miata transmission is very nice, but can't handle safely more than 250 WHP.

At stock situations or at light turbo setups you 'll not deal with problems, but with 300+ WHP the 2th or 3th gear sometimes will gone:sadwavey:

So there are two solutions
1)exotic stuff gears (os giken, quaife etc) but very expensive
2)adaptate transmission from another car, more inexpensive from the first solution but very difficult to do a perfect job.

So I put a turbo trans model "R" from RX7 fd3s (93-95).
It was from the beginning a difficult modification but the engineer succeed in this 100%.

The gear lever is exactly in the same position like the stock, and the "sense" of changing gears maybe is better than a stock transmission miata.
The 1-2-3d gears are a little shorter than stock gear ratio
The 4th is the same 1:1 ratio
And the 5th is much longer than stock ratio!! And this is very nice for a 340+ hp turbo miata!. :)

The modification based to a new housing between the block and the RX7 transmission. We modificated the miata housing (bellhousing? ) and connect to its end, the end of the RX7 housing.It was a very difficult job because it had to be perfect at straight line with the stock one.
You will see at the fotos what exactly we have do because my english are not so good to explain exactly what I want to tell.
The driveshaft was cut and modificated to match to the RX7 transmission.

How much did this cost?
Is it cheaper than purchasing the Quaife gearset offered through FM?

I dont suppose you took any pictures of the process of doing this?

Of course is very very cheapper than buying the gears!
It's the best value for money solution.

The pictures are from the mobile phone, and I think I have not pictures of the process. :mad:

FD trannies on car-parts.com are $500-1000, FWIW.

Getting the bellhousings cut and welded right is what will cost, if you don't weld.

Frank

so what about the tail? does the FD tranny have a ppf that matches ours?

no, you would need to modify it to retain the ppf. Or just make a custom mount for the tranny and the diff.

The adapter plate seems to be the cheapest solution - guys were doing that for around $300. Welding up that front to the rx7 trans and keeping it aligned was a task indeed.

friggin sweet i love junk yard shopping LOL

hmmm this maybe in my future. Closer pictures of the area you welded will help alot. What type of welding did you do this with?

Is there much difference between FD and FC transmissions? I have 3 Turbo II transmissions that I was thinking of using. And with the Price of torsens I as thinking about doing the 8.8 swap to get a bullet proof driveline.

Also wouldn't you have to get a custom clutch disc? Being that the input shaft splines are different?

No. The big difference is that the FD is setup for a ppf on the exhaust side. Nobody uses them for the swap because they cost more and it's the same center section as the FC tII. The FD rear has no "wings" for mounting, where the FC does. You need to resolve the hub/half shaft connection since the FD/FC shafts are larger. Going to the big rear though, only requires shortening the drive (propellor) shaft. Whereas keep the Miata rear would mean combining a Miata and FD/FC shaft. You will need a spline specific disk, but any clutch builder can do this since it's just swapping out the center hub.

Here's a good link on the subjects:
http://www.geocities.com/Crash41301/

Here's some excellent photos from the "miataroadster" guy- my guess is he'd make/sell you the plate:
http://billwilner.myphotoalbum.com/v...album07&page=1
- rob

thanks Rob!

The way you describe is not so good.

The reasons are:

1)The lever goes 10 cm back from the stock position
2)You have to cut chassis and modify many thinks to the car such as dowpipe etc, because the slave cylinder is from the other side.
3)It' more difficult to do, more difficult to succes the distances at the adapter plate etc
4)FD 93-95 trannie is better than an FC trannie because it's the latest version of "R" series mazda transmissions.

Nick i cant believe you arent versed IN BD lore or old you dissapointed me there. :(

what about www.racingmazda.com ? Anybody have an FC rear from them?

RacingMazda :(

I am still waiting for a simple answer to my e-mails (10 of them) about their 3 inch cat's.

I would not trust them with my money.

I am versed.....lol.... but I was just wondering why he was using a FD tranny when you can get FC trannys for a buck fifty. Plus I have 2. Just wanted to know the hoopla bout the fd tranny

Sell me one of your TII trannies one the cheap!!!

BTW SCREW racingmazda.....go hard core http://www.racingconcepts.net/product.html

I won't be home for another 30 days or so....one has 87k (inputshaft has some scaring due to a seized pilot bearing) and the other 124k (shifts like a champ)
If my ex wife didn't get pissed after the divorce they'll be in my garage and I would let go of them cheap. the first one I'd get rid of for 50 bucks....and the other 75...I should have a sixspeed by then so I won't need em.

http://www.racingconcepts.net/product.html do they have a turbo II tranny swap.? i couldnt find it on there website.

If i dont have a 6 speed in a timely fashion, i might get Bryan to put in one of your trannys since you are selling at such a reasonable price, or hell youll have a welder by then all we need from him is the plate :D

racingconcepts is all about LS v8s in Miatas- nothing turbo II.

Bigturbo- I didn't describe anything, just posted some links. Keep in mind that there are people on this forum just as capable as your mechanic, so I'd leave it to the individual to choose the method by which they would install the TII trans. Your way is surely the most expensive- and that's a $kill some of us don't have. The FD trans improvements are insignificant given the price of the FC unit. Moving the shifter lever foreward is possible, not that complicated, and the Miata lever assembly can be moved over. I bet these guys cut the shifter hole because it took five minutes. I didn't see any other chassis cutting and the slave cylinder solution worked fine. I guarantee it is far more difficult for the majority to section and weld together two bellhousings on the exact same axis vs. to make an adapter plate out of 1/2" plate. You said it yourself "It was from the beginning a difficult modification but the engineer succeed in this 100%." -BIGTURBO. Sounds to me like it was a difficult job from start to finish- and that was for a skilled engineer. My guess is that's the reason that those three guys with 400hp Miatas chose to use adapter plates.

I don't have a link, but I have seen a ppf adapter built for the TII tailshaft which retains the rest of the 1.8 setup. That's what I will do.

RandyS (solomiata.com) has come up with a solution that will allow bolting up an FD diff. It's in the middle of fabrication, but once made could be duplicated. In this case that would allow using the FD trans and ppf. Left with the usual problem of connecting that to the B engine AND finding room for the exhaust on the exhaust side with the ppf now on that side too. The reason for doing this was that the FD diff is a torsen - makes for a dirt cheap indestructible rear. - rob