Mazda’s rotary engine, for instance. And the car that was built around it.
Well, it began with the RX-7 – which first came to market in 1978. It was the heir-apparent of the Japanese (home market) 1967-’72 Cosmo – Mazda’s first production car foray into rotary engine technology.
All three were gorgeous cars; great sports cars. Quick – nimble. Technologically advanced.
And yet, they failed, each in turn.
A triple flop.
The very thing that defined them, ultimately killed them.
The rotary engine – also known as the Wankel engine, after its inventor, Felix Wankel.
Like perpetual motion and zero point energy, this unusual engine design has been tantalizing car companies for decades.
It all began in the the mid-1960s, when Mazda saw what it believed to be the future – and it was piston-less. The Japanese automaker was one of several that rushed to sign licensing agreements with NSU Motorenwerek AG, the German firm that had been developing Wankel’s idea. General Motors, AMC (the Pacer was designed around the rotary engine concept) even Suzuki (for motorcycles) bought in, too.
It is not hard to understand why.
This was achieved – well, promised – by eliminating the conventional reciprocating engine’s heavy block, with individual cylinders bored to house pistons that moved up and down in syncopation with the explosive force of internal combustion, their vertical motion translated (after efficiency losses) into rotational motion via a longitudinally mounted crankshaft. Which had to endure tremendous forces as each piston exerted downward pressure and was then – in an instant – pushed back up again. Times however many cylinders the engine had. This arrangement also tended to induce vibration – which had to be tamped down by counterweights and balancers. Which made the engine heavy as well as complex.
Instead of pistons going up and down, a kind of rounded-at-the-tips three-sided triangular rotor spins inside the crankcase, the space between each tip serving as the combustion chamber. As the rotor turns, ports are uncovered – admitting air (and fuel) and allowing exhaust gasses to escape. No energy is lost in (up and down) translation. There are no connecting rods, no conventional valvetrain.
And virtually no vibration – without any need for counterbalancing.
By getting rid of all those parts, one got rid of a lot of beef. This matters to car designers – especially sports cars designers. The original ’67 Cosmo’s engine weighed about as much as one large man (225 pounds) and two reasonably strong men could pull one out of the car (and re-install it) by hand.
The reduction in rotating mass (and stresses) also allowed very high engine speeds – 7,000 RPM for the first generation and close to 10,000 RPM by the time of the RX8. Very few piston engines are capable of reliable – and sustained – operation at such speeds. This was just the ticket for a high-performance sports car, where a revvy engine is much desired.
As is a compact engine.
The rotary engine’s high specific output was (still is) achieved without a comparable increase in displacement. The original Cosmo’s engine was smaller than many current motorcycle engines – just 982 cubic centimeters (less than 1 liter) for the original Cosmo’s Series I rotary powerplant. Yet it produced a very respectable 110-130 hp. For some perspective, the Chevy Corvair – which was being sold around the same time as the Cosmo – had a six cylinder engine more than twice the size that made about the same power (90-110 hp).
By the time of the 1990s-era RX7, the rotary engine was making nearly 300 hp (when turbocharged) out of 1.3 liters.
This is one of the highest output-per-liter-of-displacement ever achieved.
Mazda dialed back the power some when the RX8 replaced the RX7 in 2001- but the 1.3 engine was still producing 232 hp when ordered with the six-speed manual transmission.
But, there was a hair in the soup.
First, the rotary engine was – and still is – shockingly thirsty for a such a small engine. By 2011 – the final year for the RX8 – the window sticker read 16 city, 23 highway. Many V8s three times the size use less fuel. And most motorcycle piston engines of about the same size deliver twice the fuel-efficiency.
By itself, this probably would not have been a deal-breaker. Fuel economy is a big consideration for economy car buyers, but sports car buyers are usually willing to overlook a rapidly draining tank if the car delivers the goods. Which the RX8 absolutely did. It was quicker (and faster) than Mazda’s other sports car – the hugely popular but somewhat slow-pokey Miata. And it handled better than the Miata, because of the rotary engine’s behind-the-front-axle location – which conferred closer to the sports car ideal 50-50 weight balance.
That plus a sport bike engine’s capability to rev close to five figures endeared the car to enthusiast buyers.
But the car’s hungry hippo appetite was a problem for Mazda – because of federal fleet fuel economy mandates (CAFE, in the vernacular of regulatory officialdom). Each 18 MPG (average) RX8 that got built lowered Mazda’s fleet average fuel economy numbers – which incurred gas guzzler fines if the number dipped below the then-in-effect 27.5 MPG average decreed for passenger cars. With a 35.5 MPG – average, remember – mandatory minimum on deck for model year 2016, the RX8’s appetite was as much in the spotlight as Caitlin Jenner is right now. And the dilemma for Mazda was that in order to increase the rotary engine’s fuel-economy, it would be necessary to make changes to the rotary engine’s design that would likely increase its emissions of politically incorrect gasses.
Sealing problems had long been – and continue to be – the rotary engine’s Achilles Heel. Piston engines use multiple expanding rings around each piston to maintain compression and prevent oil from getting into the combustion chamber, where it would otherwise be burned along with the incoming air-fuel charge and then sent hence via the tailpipes to the surrounding air. Also, there are tulip valves (with seals) that control the flow of intake and exhaust charges – vs. the fixed-in-place ports that are covered and uncovered as the rotor spins.
The rotary engine depended on seals at the tips (apex) of each rotor to contain combustion gasses but these seals were prone to leak as well as to leak sooner rather than later, especially under hard use. The ports were also an issue, emissions-wise as there tended be overlap between cycles and some of the “bad” gasses – especially unburned hydrocarbons – tended to escape into the atmosphere.
It was not a big deal initially.
When the Cosmo came out in the late ’60s, blue smoke was as common a sight as bell-bottomed hippies in San Francisco. It was legal to sell engines that burned oil on purpose (the famous two-stroke sport bikes of the late ’60s and early ’70s) and in general the public didn’t give a damn. So long as the thing ran like stink it was ok if it actually did stink.
Then came the Environmental Protection Agency (EPA), presidential penned into existence by Richard Nixon and along with it, the Clean Air Act of 1970.
These two developments would prove to be the death warrant of the rotary engine as a passenger car powerplant – and by dint of that, The End for Mazda’s rotary-engined sports car.
And not just Mazda’s rotary-engined sports car. Also GM’s (intended-to-be) rotary-engined economy car, the Chevy Vega. It, too, was originally designed around the rotary concept. But when GM engineers were unable to get the NSU-licensed mill passed the EPA’s smog gantlet, a conventional piston-engined replacement took its place.
The same fate befell the (also-planned) rotary-engined AMC Pacer, which likewise ended up being sold with an overly heavy and underpowered but smog-approved piston engine instead. LIke GM, AMC had poured millions – in 1970s money – into the rotary engine and spent years trying to make it pay off.
It never did.
There were other victims, too. Suzuki had planned a whole line of motorcycles built around the rotary engine and even built (and sold) a few. But the whole thing had to be kiboshed and – to this day – motorcycles (not just Suzukis) continue to be powered by conventional (piston) engines.
Mazda hung in there for a long time – and managed to keep the rotary engine within plausible EPA spec all the way through 2011, in part by relocating the exhaust ports. But the changes Mazda made to the engine killed the engine’s fuel economy, leading to a Catch 22 scenario. The engine could either be reasonably fuel-sippy and and “dirty” (as defined by EPA’s increasingly unreasonable standards) or it could be “clean” (by the early 2000s, fractional reduction in exhaust emissions separated “dirty” vs. “clean” engines) and thirsty.
The cost to keep the rotary smog legal was also high – and this rendered the RX8 an increasingly pricey car. The final year – 2011 – the car’s bas price was $26,680.
Meanwhile, the Miata cost thousands less – and it handled nearly as well. It got much better gas mileage, didn’t annoy the EPA and had a well-earned reputation for being all-but-indestructible. Miatas could – and still do – run on the track every weekend, then drive their owners to work every week…. for 200,000 miles. It has been – cue Borat – a great success for Mazda.
While it is common to see 20-year-old Miatas still in daily driver service, it is rare to see an RX8 on the road at all. A few still survive, tucked under covers safely in enthusiasts’ garages – beautiful reminders of a great idea that never quite panned out.
* In addition to its unique rotary engine, the RX8 also had an unusual (for a sports car) four-door body design. An extra set of rear-hinged (“suicide”) doors that greatly improved access to the small but now-usable rear seats. While the RX8 may have consumed more gas than V6 and even V8 powered 2-plus-2 sport coupes like the Chevy Camaro and Ford Mustang, it could at least carry more than two people. The GM and Ford ponycars were (and still are) infamous for their vestigial and essentially useless back seats. The RX8 might not have gone as far on a tankful, but you could take more people with you, however far you did go.
* Beware the automatic-equipped versions of the RX8. The engine is detuned to 197 hp and torque – of which there is not much available – is virtually nonexistent until the engine is spinning over 5,000 RPM. The result is a bad case of The Slows. At least with the manual, you can rev the 1.3 liter engine up to the point in the powerband where it begins to make power (and torque). But with an automatic all you can do is floor the gas and … wait. Meanwhile, gas mileage with the automatic is even worse than with the six-speed stick. These cars were epic pigs, typically delivering about 16 MPG on average. Many V8 muscle cars from the ’70s did about the same – and they at least had torque in abundance and worked great with automatic transmissions.
* To emphasize the rotary engined-heart of the RX8, triangular design motifs were used for the headrests and other shapes within the car and outside, too. Lead exterior designer was Ikuo Maeda – the son of Matasaburo Maeda, who had been the lead designer of the RX7.
* The RX8’s “front mid-engine” layout and near 50-50 weight distribution gave the car what engineers call a low polar moment of inertia – in plain language, its resistance to turning. The RX8 turns more eagerly, with less input, than most front-engined cars.
* The ax first fell on the RX8 in the export/European market after the car was unable to meet the latest EU emissions standards. Mazda had to stop selling the car in Europe after the 2010 model year. The loss of that market – along with anticipated problems keeping the car compliant with U.S. emissions standards – resulted in Mazda’s decision to pull the plug for good after the 2011 model year.
Excerpted from the forthcoming book, Doomed.
Copyright 2015, Eric Peters
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