Mazda debuts new-gen Rotary in Taiki show car
by Dan Roth on Oct 27th 2007 at 5:52PM 
Say what you will about the styling of the Mazda Taiki concept that's currently on display in Tokyo. It's quite possible that what's underneath is more interesting, anyway. Under the hood of the Taiki is a new gen rotary engine from Mazda called the 16X Renesis. Of course, the Rotary engine has its share of detractors, but Mazda's sticking with it anyway. Further refining Felix Wankel's trochoid wonder, the Renesis (known internally as the 13B-MSP) has been massaged and enlarged for the first time in a very long time. Capacity is now 800cc per rotor, bringing total size up to 1.6 liters. Direct injection allows the 16X Renesis to put out more power and torque while running cleaner than a port injection setup would have allowed. Attention was also paid to reducing the oil consumption that Wankels are known for. The size of the engine is still pony-keg compact, and the rotor housing is now aluminum, which should save a little weight. While the new larger chamber design and direct injection offer more efficiency, it still remains to be seen whether or not the Rotary is capable of modern horsepower numbers without turbochargers (difficult with the side-port design) or swilling fuel like a sailor on shore leave. The 16X may show up in a special version of the current RX-8, or Mazda may hold off until a new RX-8 bows in 2011.
[Source: AutoWeek, Photo: Winding Road]
Reader Comments (Page 1 of 2)
Tyo 5:59PM (10/27/2007)
Cant wait to see the numbers. Any torque improvement would be greatly appreciated. 300hp @ 9000rpm anyone?
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MiikeW 9:16PM (10/27/2007)
Sounds about right.
200ft-lbs@6000, how about that?
Little Lord Poopy-Pants 6:27PM (10/27/2007)
I know many don't like the car's design, but I think it is beautiful. It has the kind of unusual surface treatment I remember from show cars long ago.
And I love the idea of a 1.6 liter. I once had a 13B engines RX-7 - still one of my all-time favorite cars.
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Turbofrog 6:49PM (10/27/2007)
Very much hope they can squeeze some realistically practical fuel consumption numbers out of that. Especially in electric hybridized form, as in the RE-Premacy, it seems the two forms of propulsion would complement each other very well for improved torque, drivability, AND economy.
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Xcountryflyer 6:57PM (10/27/2007)
Great to see the passenger rotary engine continues to live at Mazda. As a current RX-8 owner, it would be great to see more HP and better gas mileage to a fun engine.
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Mal Fuller 7:19PM (10/27/2007)
Mazda continues to build and offer rotary engines because they can. Other carmakers don't offer a rotary engined car because they can't. It's really that simple.
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zigzagz94 7:29PM (10/27/2007)
If Mazda puts this 16x rotary in the 2500lb Kabura concept it would be a 350Z killer!!!
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JerryB 12:22AM (10/28/2007)
Woow. Awesome concept. I'd love to see one with a 350hp twin turbo like the late, lamented RX-7. Fuel mileage be damned, make it as fast as it is eye-catching.
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GDUB 12:01AM (10/28/2007)
i own and love my RX8 but would love a rotary that burns less oil and gets better MPG. extra torque would rock.
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Noah 2:58AM (10/28/2007)
Gdub, by oil do you just mean gas, or you have to actually add oil to the engine (for lubrication)? B/c if its the latter, yeah, I hope Mazda fixes that.
The engine is inherently more fuel-inefficient (word on the street, that is), so I don't see dramatic improvement in fuel economy. Probably will stick around 18/24. Similar to a V6, i guess.
Also, my guess on hp for the 16x is.....~285 hp. 300 would be sweet, though.
Nucbuddy 10:44AM (10/28/2007)
Noah,
Rotaries are notorious for burning oil. It is simply the nature of that type of engine.
http://www.google.com/search?q=quart+oil+mazda+rx8
kranyx 10:10AM (10/28/2007)
I'm really looking forward to this, I have a turbo rotary right now, and wouldn't mind some more displacement :). I just hope it turbos decently with the side port design.
also, a correction to the article... rotor housings have always been aluminum. at least since the 1st gen rx7 in 79.
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leather bear 3:47PM (10/28/2007)
Exactly right; the rotor housings were aluminum for the 12A engine in my old RX2 sedan and the 13B in my old RX4 wagon (and both of those cars are sorely missed). Dan may have confused the material used on the rotor housings with the center and end sections, which were cast iron for the two just mentioned (as well as the RX7; not sure about the composition of those pieces in the current RX8 Renesis engine)
Phillip 4:35PM (10/28/2007)
Why don't the finally learn and kill this horrible engine already.
The rotary is an engineering deadend and Mazda is simply too hard headed to realize this.
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Diesel Power 5:26PM (10/28/2007)
Phillip is just too short sighted to respect an automotive company that does things differently. Should Mazda just build boring appliances like Toyota?
Phillip 5:40PM (10/28/2007)
I'm not shortsighted. Toyota, GM, Ford, Mercedes all spent millions developing rotary engines. They all came to the same conclusion. It is simply inferior to the piston engine in key aspects:
It gets very high emissions because of the very poor burn in the irregulary shaped combustion chamber.
It is very thermally inefficient compared to the piston engine becuase of the high combustion chamber area to volume ratio. Therefore a very large amount of heat is wasted compared to a pison engine.
Not to mention it has horrible reliability.
It is not simply about doing things differently. I'm all for doing things differently if they work and are worth it. It this case the con greatly out weight the pros.
Solo Racer 8:52PM (10/28/2007)
I'll bet Phillip can't name the only Japanese carmaker to win the 24 hrs. of Le Mans.
That would be Mazda, with a four-rotor engine prototype. Reliability? I think it's covered.
Your emissions and heat criticisms don't apply to the Renesis motor.
Then there are all the RX-7s raced nearly every weekend of the year.
So, Phillip, I think instead of killing the motor, Mazda should continue it just to spite you.
Solo Racer 8:55PM (10/28/2007)
As for the Taiki, it's one of the coolest looking futuristic concepts shown in many years. Those who don't get that should have to drive a PUYO in hell.
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mikeb 9:05PM (10/28/2007)
I want a 4 rotor. I swear by pistons but I must say: I'd like to hear what Clarkson has to say about the 787B.
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RG 9:43AM (10/29/2007)
I can't believe people still think the rotary is a dead concept. One might as well say "I can't believe anyone in the world would still build an archaic pushrod engine when overhead cam is the only way to go." Don't tell Chevy that of course. Keep in mind that in the 21st century, car companies were still using distributers and drum brakes on some new cars, aka Honda. I have one.
Rotaries are not inherently unreliable. 30 years ago that may have held true but then again in the 70's nothing was very reliable. The failures of the more recent engines have coem from 2 big factors. With the RX-7 it was poor cooling system design and small crappy twin turbos. That's what was unreliable. The one common things that makes people hurt these engines is that rotaries have little tolerance for stupidity. There is more of that going around when it comes to car mods than there is sensible decisions. Rotaries don't tolerate detonation. Too many people use forced induction but don't want to tune it properly. That's user error and not something to be blamed on the engine. I understand that other engines may tolerate it better but that doesn't ever make it a good thing to do.
This engine will be lighter than the current Renesis which is already lighter and mroe compact than any other engine in a street car that is out there right now short of a Smart car. It is more fuel efficient but that doesn't mean 30+ mpg. The biggest mistake with the Renesis was to put it in a heavy car like the RX-8 and then gave it a 4.44:1 rear end gearing. It needs to go back into a 2600 lb 2 seater like the RX-7. The current engine would have given 20/30 mpg all day in an RX-7 chassis. Back in a lighter car with a mroe efficient engine, we'll see an engine that is easily on par with any car in it's class when it comes to mileage. It'll never be a Prius in terms of gas mileage but I'd rather pollute than drive one of those anyways.
The most realistic numbers that this engine should put out in terms of power are somewhere around 275hp, 190 ft lbs of torque. Give or take a few but that should be ballpark. That's pretty damned good for an engine that is smaller than a beer keg.
Bring it on Mazda. I want one. Those who can, do. Those who can't, go piston.
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