Remember the Mazda rotary powered motorcycle we brought you back in May? Many of you have asked about it since then but I didn’t have any more information about it. As I was perusing the latest Cycle World, there it was again, all finished now and one of their featured American Flyers.
The bike is the work of Rodney Aguiar, who’s done work for Roland Sands, among others. He took the Mazda 13B rotary engine from a crashed 1988 RX7 and mated it to a 1995 BMW R1100GS transmission and rear end. A GSX-R 750 supplied the front. A Weber sidedraft 2 barrel brings the mixture together and helps the engine produce 250+ horsepower.
There’s only 3 gallons of gas onboard so the range is, … well, … it doesn’t go very far. It gets 6 miles per gallon, so a bit of math yields, … let’s see, 18 miles. Of course, all reports say it is so unbelievably loud you can’t stand it so why go any further?
Rodney plans to take it to Bonneville and hopes he can get it over 200 mph.
Hmm ….
via January 2008 Cycle World
Main photo: Cycle World
Related: Mazda Rotary Engine Motorcycle
taxman says
i wonder why such poor MPG…
other than that it’s pretty nice.
willie schmitz says
This bike was at the International M/C Show in Ft. Worth a few weeks ago. Interesting machine. Great craftsmanship, very well thought out and great show appeal.
Best of luck on their Bonneville effort.
Chris says
Taxman: rotary engines are generally very bad at the whole fuel efficiency thing (it has to do with the relatively enormous combustion chambers and their relatively poor thermal efficiency), although this does seem a little on the extreme side. The car it came out of, which I’m sure weighs three or four times as much, got about 20 MPG.
More on that here:
http://en.wikipedia.org/wiki/Wankel_engine
cl
Canzvt says
Taxman: Typically a normally aspirated rotary is very inefficient do the the geometrically limited compression ratio of approximately 6.5:1. Boosted engines (which this probably started life as) delivery much better fuel economy. Couple that with side drafts and average tuning (rotaries are reasonably forgiving with respect to air fuel ratios) and you get poor economy.
christopher says
unless this engine is still turbocharged on the bike then there is absolutely no way it’s making 250 HP. the turbo’d version from the mid 90’s barely made that and it was a MUCH better engine. still a cool bike though, and a bonneville run would be a pretty awesome sight.
PeteP says
Thanks Canzvt, I wondered why my RX7 Convertible only gets 19 MPG.
Canzvt says
Christopher: I would tend to agree with you that 250+ is very optimistic without forced induction. However many advancements have been made among the serious tuners with peripheral port housings and lightweight rotors. This allows the engine to breath better, but more importantly achieve serious RPM limits well in excess of 10000 rpm. There was a mention earlier of this thing being loud. I suspect that if this were a peripheral port engine with the pipes as indicated, if at Bonneville, you would need earplugs in SLC.
Mark Savory says
I remember the rotary in the old IMSA GTP days. We’d have to literally run the exhaust from the mid-engine location to the front wheel and hope there was enough sound muffling to make it past tech inspection. Eventually the drivers would have to lift throttle where the sound meters were at on every lap to keep from getting black flagged. When the factory 4-rotor engines ran on the banking at Daytona, they were so loud you could track their location easily over all the other racecars running. None of them ran in the race unfortunately — but it was an incredible sound to be honest.
Superdude says
It’s very likely that it is making 250hp as Canzvt stated. Peripheral porting, fuel tuning (even with carbs), and newer higher compression rotors would easily allow this. One of the fastest all-motor import drag cars is a first gen RX-7 with a Naturally Aspirated 13B produces around 300+ if I remember correctly.
Willie is correct that this was at the show in Fort Worth. I have several photos of it if Kneeslider would like to publish them.
christopher says
well i stand corrected. i was aware that you could push the NA rotary well beyond the factory power level, but i had no idea that 300 HP was anything more than a wish on an NA two rotor. thanks for the enlightenment. that is awesome.
gary says
A very interesting project. As for the question about NA rotary engines and power output. With a good porting job they can consistently produce 320 HP and if turbo’d will go to about 400 HP on a dual rotor. If you take the race version of the triple rotor (a 20B variant of the 13G dual rotor) and go to the max you can get 900 HP with triple turbos. A very very expensive option though and not for bikes.
It would be interesting to see if a fully worked 13B (or maybe a 13G) with forced induction, in a bike such as the above, could provide some good competition to the Y2K Superbike. You’d probably have to extend the wheelbase to prevent a back flip and move the centre of gravity forward. Hmmmmm !!
guitargeek says
Years ago, when I was building up my third Rx-7, I called Racing Beat with some question or other. I asked if they still sold hotrod motors, and the guy told me that he had a 944hp unit in a crate next to his desk.
coho says
I saw this bike at the Seattle Cycle World show this weekend.
It’s much smaller in person than it appears in photos, I was expecting BossHoss like length and width, but this could actually be a fun ride (if you were already deaf).
Easton says
Gary: sorry bro, your numbers are off. FYI: Wikipedia is NOT a good resource for FACTUAL information, talk to some of the tuners and you will find that two rotor wankels go up higher then 400 with turbocharging. The highest in my city that i’ve heard of was getting 480 on a rough tune, he guestimated it to about 530 after good tuning. And as for the 20b (not a an off-shoot of the 13G by the way, your getting confused) with a good port, and a big turbo; a three rotor engine will easily… read: easily top 1000hp.
Warwick Auckland New Zealand says
very inspireing imagine a bike with the 3 Rotor 20B the 13B pp considering usually found only in serioius race aplications i want one!!!! this is up there with the Y2k,Tamahawk V10,who ever built this is a legend.
Andy says
A typical peripheral port NA 13B rotary can make at least 300hp easily. The fastest NA 13B rotor car in the world is driven and built by Jesus Padilla. He has won the NHRA sport compact event two years in a row. The max hp I have seen a peripheral port boosted 13B rotary make is 900hp, but at that point the engine is very easy to break. The engine becomes very unreliable at that point. The engine was’t design for such high power output. We have many 13B rotary cars that make big hp.
SCOTTY says
MY UNCLE DRAG RACED A 2ND GEN NA CAR FOR A FEW YEARS.. HE MADE 500 HP AT THE WHEELS AT 9000 RPMS. HE TURNED A 1/4 @ 9.1 @147 ALL MOTOR HE CAME OFF THE LINE AT 9500RPMS AND CHANGED @ 14000 RPMS..
Vitaliy says
Poor MPG on the rotary engine because, rotary have a very huge “piston” and very small stroke like a motorcycle engine. The face of a rotor is about four times bigger than face of a piston from Toyota supra, and that is from a piston from a big engine. When the rotary go for combustion, all the gas that went in, spreads every where on the face of the rotor, and it is almost impossible to ignite. Rotary needs more fuel to run at low rpm than a piston engine, but when it gets to a high rpm, the the fuel economy evens up with a piston engine, or sometimes it’s even better. But only on high rpm. Rotary engines are like motorcycle engines make a lot of HP but not much TQ, compare to what it should have.
And yeah, 13BT could make even 700HP, but it is not that easy, it takes a lot of cash to make it reliable.
Nice bike though!
gary says
wow that looks insane ,and yep i can see it making 250+hp!
and ive seen 20b turbos pushing 1400hp !!!!!
my next project is a 13b peripheral port turbo ……for my street car,not very streetable but im down for that .
Domenique Hawkins says
Well this is another awesome looking bike. The mileage could be extended if the engineers added the miller cycle & it would keep the engine cooler. To quite the bike down a turbo would really help along with getting the bike to 200 plus mph. Would love to see this bike in action.
M.E. Nick says
you should be able to get better than 6 mpg on this engine, are you using a carburetor or fuel inject…carburetors cause more wall quenching..especially in the 13B…