Big-horsepower engines are nothing new to the Ward's 10 Best Engines competition. Even big-horsepower engines at incredibly accessible prices are not unusual. Those two attributes provide the foundation of a good 10 Best Engines resume.
It's no wonder, then,Motor Corp.'s sizzling new 2.3L DISI turbocharged DOHC I-4 lands in the winner's circle for 2006. Few hoods in the U.S. market cover a hotter engine that costs less.
's 2.3L 4-cyl. pounds out a Ferrari-like 119 horsepower per liter, but the Mazdaspeed6, in which it serves as the standard engine, costs less than a tuneup for a Ferrari.
This engine/vehicle combo crosses into several segments – yet beats competitors in all of them.
Some might say the main competition for the Mazda mill is the edgy, high-output turbocharged 4-cyls. powering its obvious Japanese rivals, the Subaru WRX STi and theLancer EVO.
The Subaru's turbocharged 2.5L DOHC H-4 and's turbocharged 2L DOHC I-4 both crank out slightly more power and torque, but Mazda's 2.3L turbocharged DOHC I-4 is demonstrably more refined and driveable, not to mention less expensive.
Thanks to the complimentary technologies of direct injection gasoline (DIG) – Direct Injection Spark Ignition (DISI) in Mazda-speak – and turbocharging, Mazda's 2.3L 4-cyl. is quieter, has less spastic throttle response and presents a broader power band than the stun-grenade 4-cylinders of its Japanese rivals, whose engines constantly bark like a riverboat captain when compared with the Mazda engine's cultured Anthony Hopkins tones.
Mazda has taken its widely known 2.3L “global” 4-cyl. foundation and applied DIG technology to increase torque and improve economy and emissions.
As we have seen with this year's other 10 Best Engines winner that uses DIG and turbocharging in concert (Audi A3), there is no better teaming of technology.
The enhanced low-rpm torque production that comes from DIG sweetly compensates for turbo lag.
While most non-DIG turbocharged engines wallow at low speed, waiting for their turbos to wind up, the new DIG turbo mills snap to attention directly from idle. When the torque benefits of DIG are bleeding off at higher rpm, the turbocharger already is making efficient boost. Magnificent!
It helps that Mazda's foundation architecture is excellent, including high-cost items such as infinitely variable valve timing, twin balance shafts and strengthened internals.
Mazda engineers' adaptation of their global 4-cyl. with DIG and turbocharging produces one of the year's genuinely special high-performance engines.
Banks: Girl next door, with a naughty streak.
Murphy: A zesty twist to a mature vehicle architecture.
Winter: Strong at surprisingly low rpms.
McClellan: Too much torque in first gear.
Visnic: Totally explosive mid-range torque would give a 911 trouble from 50-90 mph.
Mazda Motor Corp. 2.3L DISI Turbocharged DOHC I-4
Engine type: 2.3L turbocharged DOHC I-4
Displacement (cc): 2,260
Block/head material: aluminum/aluminum
Bore x stroke (mm): 87.4 x 94
Horsepower (SAE net): 274 @ 5,500 rpm
Torque: 280 lb.-ft. (380 Nm) @ 3,000 rpm
Specific output: 119 hp/L
Compression ratio: 9.5:1
Fuel economy for tested vehicle (EPA city/highway mpg): 19/25
Application tested: Mazdaspeed6 GT