another solution might be marinizing a set of flat 8,10 or 12 cyl engines. give you the compact hieght with a slightly more converntional powerband.

Going to rotary power is more out of necessity than novelty. Outboards are too expensive (four of them) and clutter the back end of the boat. V8s simply gobble up too much head room preventing a nice continuous floor from the helm back to the transom. Pancake engines (VW, Porsche, Subaru) would get to be too expensive.

Horsepower levels have to start conservative. But my wishes of the rotary are not some pie in the sky dream. I have had excellent results in a jetski application with continous max power. But where I take my lead from with continuous power versus reliability claims is the aviation community. The aviation guys are quite wise when it comes to TBO, simplicity, and failure modes. Some Aviation TBO claims are 3000 hrs at 150 hp for a Mazda two rotor. At cruise, I would suck down 300 hp per side...so what, four rotors and I get 3000 hrs? I'll have to rebuild the boat before the motors!

The thought crossed my mind today that maybe this has to be a 6 rotor naturally aspirated rather than a turbo 4 rotor. I can easily get 600 hp in naturally aspirated form from a 6 rotor and not deal with the detonation issues and low end torque problem inherent with a single turbo rotary. Naturally aspirated rotaries love low octane. So if this is the path, then it sounds like figuring out a reliable coupling mechanism between motors is the key. One company has been working on a six rotor, but I'm not sure where they are with it.

I've heard from credible sources that ceramic apex seal rotaries can withstand deto without issue. But, they are $2000 a set (for two rotors). It's all about how far I want to take this but at the end of the day, I want my old 37 Baja to hit the 70s...reliably....and with all the space and not the expense of other methods.

As a side note to speak of rotary robustness...I've run my rotary jetski without oil for about 5 minutes (oil line broke and I didn't believe the oil pressure gage when it read zero). After filling it up with oil, the engine proceeded to run for another 4 hours before developing a vibration. Upon disassembly, the one rotor journal bearing was chunked up pretty good. So, I'd have to say that is an acceptable failure mode....try that with a Chevy at max power! But, I'm not here to diss the Chevy. If I could get Chevies to fit in the boat I want to have, I'd do it.

I think it would be more practical if you can make the power you want/need keeping the motors NA. Boost just kills rotory reliability and making high HP would be a real challenge to quiet those motors enough while not restricting flow and causing another potential detonation problem. High HP rotors are awesome!..When they are not broken!! haha If you want to stay boosted, Why don't you build one of the motors, Bring it to a dyno with load control and see how it holds up? Would be a shame to go through all the trouble of rigging the boat with them to find out the motors wont handle it well. If it doesn't hold up $$ spent wouldn't be too bad. I am also very underdog appreciative person!!! Try it out...You never know!

I was interested in putting two turbo RB30 engines in my boat. When built right these have same bore/stroke as the 2jz but they have variable valve timing on the intake cam to aid help turbo lag and GREATLY increases low end torque. Costs will not allow me to pursue. :mad:

They are available................
 

Peak torque is 184ft/lb @6700rpm
Peak Horsepower is 275hp at 8500rpm
164 torque @ 4500rpm!!!!!!

Boooooo! haha j/k But those number need alot of work... Put a 7k stall converter on it?? haha

rexx, i'm absolutely intrigued with your concept. i've loved rotaries since the mid '70s when my brother and i raced matching rx4s; the damn things were built-proof. i think your idea for 6 rotors a side (3x2) naturally aspirated is a winner.what an interesting concept, an offshore boat with a lot of room in the cockpit. 600 hp a side will get your boat in the 70+ speed range you like. i also like the surface drive approach unless of course the konrad guys want to send you over a couple of test units. keep us posted. - jeff

Hey man, I just pointed out marinized parts are available. I have no connection with Atkins or their partner:
http://www.camdensuperchargers.com/

I was just messing around..lol

It's settled then...time to get to the drawing board.

The correct prop and about 6 rotors per side should do. Wonder what 12 rotors will sound like....must have muffler!! Start out naturally aspirated...then maybe a supercharger or a few turbos will find their way on the setup...maybe just some higher RPMs. Can't put too much horsepower into the old Baja or it's likely to experience rapid disassembly...

I'll post pictures as the project progresses.

http://www.youtube.com/watch?v=bpxK2ub-qCs
Obviously not a good setup for your needs but this thing moves pretty damn good!