Has there ever been a 3 rotor 12a?

If not can a 3 rotor 12a be made?

Has anyone seen a carborated 3 rotor?

The only thread I could find that crossed a 3 rotor with a FB
https://www.rx7club.com/showthread.p...+rotor+1st+gen

 

Not by Mazda.

Yes.

Yes.

Then you aren't looking hard enough.
https://www.rx7club.com/search.php?searchid=6218192

 

The main thing that makes a 3-rotor 12a hard to do is the e-shaft. It has to be custom made, whereas with a 20b you can actually get an e-shaft and appropriate 3rd iron because the engine was produced by Mazda and sold in Japan, New Zealand and Australia in the Eunos Cosmo.

You can get entire 20b motors, or just the parts to make a franken-20b, whereas with a 3-rotor 12a you need to get a custom e-shaft, custom tension bolts, custom counterweights and figure out how to make it work with two middle irons. There's no bearing support in the regular middle iron so with a 3-rotor 12a you can have shaft bending/warpage at high rpms.

Not to mention a custom oil pan, intake manifold, exhaust manifold.....

That's why the 3-rotor 12a hasn't been done much.

Jon

 

Hurley Engineering used to sell a 12A-based side-port 3-rotor with three SU carbs. I believe it was supposed to make 250 BHP.

 

scoot made a 4 rotor 12a..

http://vids.myspace.com/index.cfm?fu...=608393899&n=2