Transmission alternatives to the B3/B6 motors?
 

Being that everyone says the early Miata transmissions do not handle power well, what other RWD Mazda transmissions are available that can handle a fair amount of power?

I have read that the RX7 transmissions will work with the Miata bellhousing and vice versa. This is for a straight line, land speed project I am commuting to. I already have the engine and chassis I intend to use, I am just trying to weigh my options for the drivetrain.

And if there is anyone who offers adapters for say a GM transmission, a Ford transmission or anything big and old, I am certainly willing to entertain one of those.

Again, this is for a big horsepower B3/B6, rwd build. Thank you in advance for any help. I just cannot seem to nail down any solid answers by simple searches.

BMW transmission. Seems like it would have been hard to NOT run across information on that in the last couple years.

KMiata has a solution.

To be honest, I had not dove to far into my search here yet. Other places, just not here. I spoke with the owners of Kmiata and it seems like that is my solution unless I source other avenues on my own. The GM tranny idea still is appealing. I appreciate the info and at least I have a solid avenue to pursue.

Thank you

you're building a land speed Miata? or just a b6/bp powered vehicle?

It will be a B3 powered car. I have seen three or four Miata's at Bonneville. I just have to be different even though the Miata fits into quite a few classes.

At the front of my mind it will be a B3 block with a B6ZE cylinder head. I can make the B3 head work but, if I can figure out the valve clearance for a B6ZE work with the small bored I have a lot more potential for horsepower.

The car is being slated for the H/BGC class. H is the engine size ((62-92.99 cubic inches)(1.016-1.523 liters). Blown Gas Coupe is the class I am targeting even though I am handicapped by running leaded race fuel instead of the normal E85 or Methanol we run in our Mitsubishis.

I have been dying to build a Festiva for years and years but, I love the vehicle I am going to be doing the build for and will slowly convert it from my daily driver. I just cannot get rid of the vehicle and being different makes me enjoy it that much better. And what better way than use what I already own and have sorted out. The Festiva build I had in mind I was intending on running would likely be a faster chassis potentially (class rules state a stock body with no aero work or air dams).

Iirc the combustion chamber on the 1.6 head is bigger than the bore of the 1.3. So you end up with some weird overhangs that can't be good for performance. The valves may hit the cylinder walls also. You're probably better off trying to find a festiva gtx engine which is just a destroked 1.6. Some guys are trying to build one using a rio crank. Just waiting for the crank to find its way to the shop to see if it will be possible. Don't know if a stiva will have more potential with a stock body they're bricks compared to miata.

Edit: You can run up to 1.5l have you looked into the b5/z5/zl engines at all?

I meant as compared to the chassis i intend on using. I have never owned a Miata. I am aware of the difference with thr 1.6L head with the bore size. I will have to wait until the engine gets here before I can start working on clearance.

I am not sure where I would source a B5. And it is pretty strict on the engine class. The B5 looks like a viable option as even an over bore keeps it under the class limit.

B5 was available in usdm protégés. Someone on festiva forum did a write up of differences between it and the dohc 1.6. You really should look into the z series engines though. https://www.miataturbo.net/build-thr...e-build-62722/

The zl is a 1.5 with a better flowing head that came in jdm protégés. There's a few on ebay for under 700ish