In the early 90's I read about a NA 20B. I am in the research stage of building a Lotus (Locost) 7 and I am considering using a NA 20B as a powerplant, if they are available. I was wondering if you guys could point me in the direction on where to do some research on these motors. TIA

 

The NA 20B (replacement for the 13G) was and is only available to racers, and has never been in a production car. It is rather expensive, so if you don't need it for the track (ie dry sump, peripheral port, etc.) then it may be cheaper to buy a used 20B-REW (approx. $4K used) from a Japanese-only JC Cosmo and modify it as needed. Before you start building your car, note that the 20B engine mounts are located on the block in a different place than the RX-7 13B engines.

Race 20B engines/parts:
http://www.mazdamotorsports.com/weba...0001&langId=-1

Apparently Roger Mandeville can build you a less-expensive race 20B for around $28K. I'm not sure what all that includes, but his shop is one of the premier rotary businesses in the world, so it wouldn't hurt to call:
Mandeville Auto Tech
Roger Mandeville
350 Simuel Rd.
Spartanburg, SC. 29301
voice: 864-582-0038
fax: 864-585-3353
e-mail: rmandeville@mindspring.com

Some 3-rotor links:
http://www.3rotor.com/
http://www.geocities.co.jp/MotorCity/6881/
http://www.dmrh.com.au/ (See JC Cosmo)
http://www.atkinsrotary.com/
http://www.rotaryaviation.com/custom_mazda_engines.html

 

OK. Thanks for the info. I'll think I'll strike the NA 20B from the list.

 

Why not... take a 20B-REW pull the turbos off, install S5 high compression N/A rotors, bridge port the housings. Then you have hell of a N/A 20B. Jesus Padilla runs a setup like this in his all motor drag car.

 

even with a street port it would be pretty fast...

mike

 

Yeah he is talking about putting this in Lotus 7 copy. it would be more than fast. A mild 13B would get a 1200LB car moving.

 

a stock 12a would be fast, a ported 20b might be insane, but in a good way

mike

 

LOL, it definitely isn't the cheapest way to go. I think a good used 20B-REW would be better on a street car than a loud NA which would require additional engine mods. Even a used 20B-REW is going to cost you around $6K to get running, though.

If you are looking for a good affordable alternative, you may want to check into a J-Spec 13BT and aftermarket EMS. That's probably going to be your best bang for the buck, and with the right mods it will have just about the same peak hp as a street 20B NA. A 1200 lb car doesn't need torque, hehehe.

I saw a 3-rotor Viking in Kit Car magazine a few years ago. It's basically a Lotus-7 type car, and I'm sure it was scary-fast.
http://www.laminarauto.com/

 

I found the Viking article, and I will keep it on my web page for a few weeks for those who want to download it.
http://www.geocities.com/evilaviator/viking

 

Hey you stole my idea! =)
I already have a TII so I want to do something with my na. Im in the process of scoring a TII driveline for it. How about a 20B, headers, points, and sidedrafts. Im not sure what you could really do about the carbs but I dont want to got FI, if I ever get one.
Oh heres a good article. It made me want to dump both cars and save to import a stock cosmo.