Just a couple of gearshifts at that glorious 9,000-rpm redline would make Henry Ford himself admit there’s plenty that’s special – necessary, if you will – in what Mazda Motor Corp. has done with its new-age rotary. Blockbuster films are fine, but every now and again, you’d like to use your brain a bit. The Renesis rotary’s second consecutive Ward’s 10 Best Engines win confirms that uniqueness remains a vital quality in powertrain development.
Like a low-budget indie, there are ups and downs, though. On the positive side for the Renesis is its remarkable and otherworldly noise, vibration and harshness “signature.” This, because there is little vibration or harshness. The noise, meanwhile, is thrilling, maybe even a little anxious at times: an angry-bees-in-a-tincan snarl that never annoys, but always warns there’s a certain “power” thrumming around in there.
Mazda latest-generation rotary unique to a fault.
Some critics say that power, 238 horses for the “high-power” Renesis that is hooked only to a delightful 6-speed manual transmission, is a bit meager. But the big problem, as it always has been for the Wankel design, is torque. The 159 lb.-ft. (216 Nm) is practically laughable, and if the driver is inattentive or clumsy with the throttle and clutch, blue-hairs in Honda Elements can be trouble.
No, to get power from the Renesis it must rev, and that’s okay, because with the rotary, the lack of pounding common to reciprocating piston engines is absent, so the universe is in equilibrium. But make no mistake, Renesis’ torque stinginess can be uncomfortable, the only characteristic Ward’s testers mention with regularity.
Then there’s the fuel-economy controversy. Mazda’s official ratings for the high-power RX-8 of 18 mpg (13 L/100 km) city and 24 mpg (9.8 L/100 km) highway are not intrinsically awful. But for a tightly wrapped sport coupe that barely surpasses 3,000 lbs. (1,361 kg), those aren’t Friends of the Earth numbers. There are rumors Mazda’s tried some engine-management tweaks for customers who really complain, but we’ve yet to understand the extent of any such program.
It’s impossible to dwell on the Renesis rotary’s limitations, though, when the thing literally spins its heart out whenever it gets the chance. There’s simply too much that’s too special about this technically fascinating engine – and the incalculable economic and intellectual investment Mazda’s made over the last 40-odd years – to see the rotary’s eccentricities as anything but tolerable character flaws to be expected with uniqueness.
“I could work with this engine all day,” says one 10 Best Engines judge. We think that’s the reaction Mazda sought four decades ago. The Renesis rotary engine is an inspiration to engineers and enthusiasts alike.
|1.3L Renesis Rotary|
|Engine type||1.3L twin-rotor rotary|
|Bore x stroke (mm)||N/A|
|Horsepower (SAE net)||238 @ 8,500 rpm|
|Torque||159 lb.-ft. (216 Nm) @ 5,500 rpm|
|Application tested||Mazda RX-8|
|Fuel economy for tested vehicle (EPA city/highway mpg)||18/24|