Anyone Ever try a Mazda Rotory W/ a mercruiser outdrive?

[mylesm260]

http://www.atkinsrotarymarine.com/

These guys make kits to install mazda rotory engines in boats using mercruiser legs. Anyone have any experience with those kinds of setups?

My understanding of a rotory in a boat is:

Pro:
weight
fuel consumption at higher speeds
reliability


Cons:
Engine life
Low End Torque
RPM Range (would higher rpms be hard on the drives?)
fuel consumption at lower speeds


Those mazda 13B's are stupid simple, and you can make amazing power with them without any risks of blowing them up. Only problem is they burn a lot of fuel at lower rpms and they don't make much torque down low...

 

[chiefalen]

Re: Anyone Ever try a Mazda Rotory W/ a mercruiser outdrive?

Wow let us know how it works out, i for one am interested to see how it works out.

 

[HT32BSX115]

Re: Anyone Ever try a Mazda Rotory W/ a mercruiser outdrive?

No reason why it wouldn't work.

They provide all the mounting hardware, jacketed marine type manifolds etc.(these people are just down the road from me.....)

You would also need a drive ratio and prop pitch to take advantage of the rpm/torque characteristics of the rotary.



Oh......you'll need a pile of cash too!!


Cheers,


Rick

 

[Barnacle_Bill]

Re: Anyone Ever try a Mazda Rotory W/ a mercruiser outdrive?

Do they still make those rotary engines? I haven't kept up with it.

 

[chiefalen]

Re: Anyone Ever try a Mazda Rotory W/ a mercruiser outdrive?

Mazda has one in one car they make. How much hp and torque that baby make.

All the other specs please?

 

[mthieme]

Re: Anyone Ever try a Mazda Rotory W/ a mercruiser outdrive?

Good candidate for a hydroplane.
Way back when in another lifetime when the RX-7 used these and I was still a mechanic...one of my close friends at the time was factory certified to work on these puppies. Four moving (internal) parts, 10K rpm, ... what potential .... what ever happened to these ? Seems they would be a good choice for many applications.

 

[Don S]

Re: Anyone Ever try a Mazda Rotory W/ a mercruiser outdrive?

All their torque and horsepower charts start at 4600 and go to 7 or 8000 rpm. Outdrives aren't going to take anything over 5000 rpm.

Our marine bellhousing will fit the following inboard engine for through hole drives: Borg Warners, Velvet Drives, and Hurth Mercruisers. It will also fit IO units with a proper adapter plate

What's a proper adapter plate.

The big thing is low end torque. That's what outdrives need.

Neat idea, but impractical. With an almost $12,000 cost estimate without an outdrive, or the special adapter plate or any of that stuff, you could install a

Which would you rather have an $11.640 rotary engine package with around 170 hp, that you have to adapt to some kind of outdrive with some special adapter.
Or, for the same price, this.
http://www.marinepowerservice.com/BoatingStore/browse_detail3.cfm?productID=23530

 

[HT32BSX115]

Re: Anyone Ever try a Mazda Rotory W/ a mercruiser outdrive?

Pro:
weight
fuel consumption at higher speeds
reliability

Actually one of those items is a con....

The rotary has always shown a tad higher BSFC (Brake Specific Fuel Consumption) than piston engines. (not excessively large but about 10% or so more)

This is why they never really "took" for aircraft or other static rpm applications like boats, generators, etc....And when you compare them to diesels, They exhibit almost double the fuel consumption.

 

[mylesm260]

Re: Anyone Ever try a Mazda Rotory W/ a mercruiser outdrive?

That's why I said at high speeds

Their supercharged 1 rotor setup has better BSFC than a typical marine piston engine, but only in the upper RPMS.


Don: The engine makes 275 HP, and from the looks of it, needs a special adapter to work with a stern drive.

I agree, not practical whatsoever, especially considering I'm running a 200 dollar rebuild junk yard 4.3 in my boat making 220 HP =)

On a side note, the new RX-7 will be coming out in 2010 with direct injection.... way more power and way less fuel consumption than it's predicesor

 

[Don S]

Re: Anyone Ever try a Mazda Rotory W/ a mercruiser outdrive?

Don: The engine makes 275 HP,

Yea, at 8500 rpm. Outdrives start saying good buy at rpms over 5000.
I was giving the HP rating a break at 5000 rpm saying 170 instead of 165.

Still can't find any info on that "Special Adapter" for an outdrive.

If one was to have one installed in a boat, it would need to be a rich guy that wants a conversation piece.

I just can't see the rotary engine technology in boats going anywhere. Doesn't even go over very well in the automotive circles.

 

[Lou C]

Re: Anyone Ever try a Mazda Rotory W/ a mercruiser outdrive?

An interesting idea, but for marine applications, in an IO doesn't really make sense for the reasons mentioned. I recall reading that at one time OMC experimented with a rotory in an outboard application, where the light weight would be a plus and the high rpm operation is maybe less of an issue. But I don't think it ever got beyond the experimentation phase, although they did build a few for racing. The reason why rotaries never went into widespread use was that the early development problems bankrupted the first manufacturer to use then in cars (NSU used them in the RO-80, a very advanced Wankel rotary powered front drive car of the 60s) and then Toyo-Koygo (parent company of Mazda) bought the rights to use it, but it nearly bankrupted them too because they had lots of problems with the rotor seals in the first gen rotaries sold in the early 70s. In fact GM had a program under way to build rotaries under license as well but with the oil shortage, they shelved the project and went with conventional (poorly executed) 4 cyl engines. The first generation Mazda rotaries ran great, revved like hell, were much smoother than any 4 cyl car engine, but used more gas than most of them. They had trouble getting the apex and side seals to last longer than about 35000 miles. Mazda put it on the shelf, focused on piston engines, and brought out an improved version for the 1978 RX-7, which sold well until it and the other Japanese sports cars priced themselves out of their market. It's still sold in the RX-8 today, but modern 4 cyl engines have gotten so much better in power output and smoothness, that there is not such an advantage of the rotary any longer.

 

[chiefalen]

Re: Anyone Ever try a Mazda Rotory W/ a mercruiser outdrive?

Woa everybody who are we to tell a neighbor from the north not to do something.

We can point out the negatives, or just say go ahead wow what a great idea and let us know how it turns out.

So it's gonna cost 3 times what a similar set up would cost if he went with a merc lets say, so what he will have something different. Oh yea he has a way also to make the drive work also i'm sure.

I'm not known to be a negative kinda guy, go ahead show us what ya can do.

Post plenty of pics please cause we all love to see pics.

Good luck in all your endeavors !

 

[mylesm260]

Re: Anyone Ever try a Mazda Rotory W/ a mercruiser outdrive?

I have no intention whatsoever of using this setup.....

Don's 100% correct... you would need a gear ratio and prop pitch to get the RPMS to work, and even then it would have no hole shot.

Those RPMS on the drive would make short work of it aswell... I believe the drives could handle say 5500, maybe even 6K but certainly not 8K

I have a friend who's building a race rotory, and he came across the site, so I was just wondering if anyone in here had any experience with it.

Rotarys are really cool in that you can boost the snot out of them and they hold together. If you guys are bored, go research peripheral ported turbocharged rotary engines. Very cool.

 

[chiefalen]

Re: Anyone Ever try a Mazda Rotory W/ a mercruiser outdrive?

Na i ain't gonna research nothing i ain't ever gonna do.

I ain't gonna waste no ones time ether asking about something i ain't never, ever gonna do.

But if you do get around to building this wrankel powered boat please let us know how it works out, and pics don't forget the pics we love pics.

Good luck !

 

[hanahawaiian]

Re: Anyone Ever try a Mazda Rotory W/ a mercruiser outdrive?

i build few Rx-7 Racing... but 13B (2rotory) and 20B (3rotory) are pain in *** to work on it... but It pretty fast can go over 10k rpm redline and slap bigger turbo and it awesome..

 

[DJ]

Re: Anyone Ever try a Mazda Rotory W/ a mercruiser outdrive?

There WAS an outfit that had developed a self contained Rotary Jet Package. The package hung off of the stern similar to an outboard on a bracket.

It looked promising, fairly lightweight and the Rotary makes sense in a jet (RPM'S).

I Googled it and didn't see anything.

To work with a sterndrive, I would think the rotary would require a gear reduction, before the drive. That would be complicated/expensive and the weight advantages start to disappear.

The Mazda RX-8 is a ball to drive though!

 

[hanahawaiian]

Re: Anyone Ever try a Mazda Rotory W/ a mercruiser outdrive?

Most baller is 20B in RX-7 or 8

20B 3 rotary is from Small airplane.. but it fit in!

http://cp_www.tripod.com/rotary/pg20.htm