Where the heck are these engines from and what versions can you get 'em in?

 

It's an engine from the Japan-only Mazda Cosmo.
It has a 3 rotor engine (20B).
"Basically" just a normal 13B (RX-7) engine with an extra rotor added on.

I'm not sure about power output, but I know a stock 20B with stock 3rd gen twin turbos at 12.5psi boost makes approx. 550hp.

 

The 20B comes in only one version: Twin-turbo, 3-rotor, fuel-injected, automatic transmission. The JC Cosmo wasn't sold in North America, so you will need to find a specially-imported engine. I got mine from Ray Lockhead:
http://www.srx7.com/

Yes, that's it basically, but it's more like the Cosmo 13B, not the RX-7 13B. Compared to the RX-7 13B, it has different engine mounts, intake, turbos (similar to a 3Gen), and some other stuff.

Pettit gets 550HP with stock turbos and a ported engine with aftermarket EMS and other goodies, but 550HP is also possible with the stock ports if the boost is upped to a less-reliable level. The 20B was rated at only 276HP (probably a lowball figure) as installed in the original JC Cosmo.

You can learn more about the Cosmo here:
http://www.3rotor.com
http://www.dmrh.com.au/

Here's a good site on a 13B Cosmo FC conversion:
http://www.wickedrotary.freeservers.com/photo.html

Here are sites on 20B Cosmo FC conversions:
http://www.3rotor.com/chito.htm
http://www.cris.com/~Asam/20B.html
http://www.geocities.com/neo_beta1/20B_FD.html
http://www.k2rd.com/Projects/20B/20Bpics.htm

Sites with my 20B FC:
http://home.talkcity.com/ThePits/spinracing/index.html
http://www.spinracing.net/
http://www.rx-7.cc/edgar/auto/rx-7picnic/index.htm

 

That's about what the 3 rotory rx-7 concepts made in 88 were tuned to. It buys you more low end torque and greater performance potential.

 

I accidentally gave you an FD 20B page instead of this one:
http://www.se-rx7.com/20b/

This is probably the best site out there for those interested in a 20B swap for an FC.

Hehehe, as you can tell, I have been researching this a bit.

 

well then you might want to research it some more, because the cosmos 20b did not only come in one version, it came in a turbo and non-turbo version. my friend has a 1st gen cosmo with a 20b NON turbo.

 

Does anyone know what a 20B conversion costs?

 

OK, I really like research ...

A Cosmo brochure from 1968 - no 20B engine, though:
http://www.eunos.com/keith/110S/
Hehehe... Our engine runs circles around your engine!

Hmm, a 20B rotor comparison, but still just 2-rotor engines:
http://members.nbci.com/craigpage/PG16.HTM

Nope, no 20B for the 1Gen Cosmo here, either:
http://www.monito.com/wankel/engines.html

Und der Cosmo ist heir mit dem 2-rotor (kein 20B):
http://www.der-wankelmotor.de/Fahrze...smo_sport.html
... aber ich habe das drei-rotor flugzeugmotor gern!
http://www.der-wankelmotor.de/Motore...-vaz-lada.html
(Sorry, I got off track)

Man, my research is really lame - No 20B NA 1Gen Cosmo anywhere! I guess it could be because the 20B wasn't developed until the mid-80's, but I like to keep an open mind.

Help me out here, where can I find a 3-rotor NA 1Gen Cosmo?

 

It all depends on how you do it and what resources you have - the engine swap is a process you go through, not a part you can order from Nopi. To do everything yourself will probably cost at least $10,000 to convert an FC or FB, and a little more for an FD because of the subframe. It would cost less in 20B-friendly countries like Japan, Australia, and New Zealand. Pro builders like PFS and Pettit will do the conversion for around $40,000 - $50,000.

Here's a recent link on the subject:
https://www.rx7club.com/vforums/show...threadid=17205

 

i dont know a site on them, but its a first gen cosmo, but im not sure the year. but its a 20b non turbo. known for a fact

 

$40-$50 grand is a lot. You think a Renesis conversion will be any cheaper when the time comes? For an N/A.

 

The N/A 20B started life out as a twin turbo 20B from the latest Cosmo (late 80s through the mid 90s) line up. Mazda never sold 20B as N/A, only twin turbo and only in the Cosmo. Of course that never stopped anybody with the money and imagination from swapping the 20B and making it N/A. Out of Japan I've seen in a magazine a FC with a carbed 20B N/A. The Option video specifically for the RX7 (#33 I think) has a N/A 20B in a FD doing a top speed run on a test track.

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