"Turbo Alternative" from Rotary Engineering
 

The engine built by Rotary Engineering more than a few years back was apparently based on a four port 13B with Weber 36 carbs, hardened front and rear stationary gears, locked rotor gears and something tthey called a "rallye" port configuration and nitrited cast iron housings. Supposedly it sold originally for about $3,200 back when.

Even though the engine sounds good, it only generates about 225 horsepower according to the ad in Rotary Review number 23.

So, a question is whether it is really worth buying in an old "81 RX-7 with a litte rust and not a good paint job given the much greater horsepower available from a turbo setup.
https://cimg3.ibsrv.net/gimg/www.rx7...2e38ec0c8b.jpg


A second question for knowledgeable others is whether a different port configuration besides whatever a "rallye" port configuration is would boost the horsepower enough to be worth the trouble.

It really all depends on what you're looking for and what your goals are to be honest. I'd be happy to ask Dr. Wayne Graham (founder of Rotary Engineering) specifics if you'd like. I work with him almost every day.

First question.... no, you need to turbocharge whatever RX7 you get; every side port rotary needs (requires boost)


Second question. Peripheral port. 787 nuff said. If ever I buy an RX8 I'll build a PP engine for it with webbers or IDA carbs.

Did the engine in your rx start life as a turbo or was it an NA? Whats your opinion of turbo'd NA's?

It was a 4 port turbo engine. 12A's run low enough compression so you don't have to worry about detonation.

Don't turbocharge 6 port 13Bs.... not only for compression reasons but port timing is not optimal for turbo. Just buy some Tii rotors and use those.


Never witnessed a 2000# FB. My first RX7 was 2300 with me in the car (I don't weigh but 180). It had no a/c, RB headers, and no spare tire, no sunroof, and lots of rust chipping off lol.

200whp? NA? that's asking a LOT. Not un doable but a lot. Way easier to bolt on a turbo and tune a carb imo. To make a 200hp NA car you'd have to make an exhaust; you have to make an exhaust for a turbo car. To make a 200hp NA car you'd have to tune the crap out of a carb; you have to tune the crap out of a carb when you turbocharge. To make 200hp from NA you'll need a bang up ignition system; turbo cars require a bang up ignition. Then after its all said and done the turbo car is making more power same effort.


I'm not saying NA is worthless. YES if you are racing; an NA V8 is the way to go, but rotary exhausts are SO powerful. Why not use that power?

It would be much appreciated if you could ask Graham for more information about the "rallye" port configuration. It must be something like or the same as a "street port"?

It was just their marketing name for their semi large street port. It's the basis of the port that we developed for E Production racing which was designed to be an 8500rpm port with as broad of a power band as could be made while also hitting the ~270ish horsepower goal.

lol..... It was a 4 port turbo engine. 12A's run low enough compression so you don't have to worry about detonation. u always hav to worry about detonation

No it wasn't.

I have one of these Turbo Alternative 13B motors from an FB that I sold the shell to. I was messaging with dguy previously, but the new forum rules mean I don't have access to PMs anymore, so I'm posting here for more help. I have photos, and I'd like to confirm that I do in fact have one of these. It's a 13B with the Rotary Engineering dual Weber 36DCD carb intake setup, and I have a folder of paperwork with information on the "turbo alternative", so I assume that's what I have. I'll try to post my photos somehow for anyone interested.

Here is a link to a Google Photos album of the engine. It still has a trans attached to it, which I believe is a four-speed.

https://photos.app.goo.gl/bLUDSKMFDWHKT7pY7

I can take more photos of specifics as well, let me know if anyone wants to see anything.

The final question would be, how do I investigate the condition of this thing, if it is in good working order or not? I was considering keeping it for some kind of crazy project, but that's not in the cards right now, so I'd rather sell it to someone interested in using it. But it would help to know what kind of condition it's in for selling, so if anyone has advice I'm all ears.