Yank the emergency brake in the new Mazdaspeed6 at speed and the car's all-wheel-drive system automatically disengages drive to the rear wheels. The fact that this ham-fisted, ass-out, "Dukes of Hazzard" buffoonery was a design consideration is Mazda's way of saying it cares.
The "zoom-zoom" Mazda6, whose superb chassis and eager V6 have inspired positive reviews and solid sales, has nonetheless fought for parking spaces among the enthusiast population.
Mazda invited us to hammer on early prototypes of the new Mazdaspeed6 at the 1.7-mile TI Circuit in Okayama, Japan. Home to two F1 races in the mid-'90s and a favored JGTC track, TI Circuit offers flat-out sweepers and long straights with several hairpins. Its liquid-black pavement is smoother than R Kelly, but didn't offer the real-world driving conditions we need to wholly evaluate a proper all-wheel-drive sedan.
That's right, all-wheel drive. And that V6? It's gone too, in favor of a turbocharged version of Mazda/Ford's 2.3-liter inline four. The heart of the Mazdaspeed6 is the most powerful Mazda engine currently in production.
Mazda, which until recently suffered with relatively low-tech piston engines, revamped its entire line with an infusion of technology. The basic architecture of the Mazdaspeed6's 2.3-liter is shared with the inline, aluminum MZR four also used in the Mazda3, but features a host of Mazda's newest technologies.
Most notably, fuel is injected directly into the combustion chamber with Mazda's Direct Injection Spark Ignition (DISI) system. Direct injection, which reaps performance, emissions and fuel economy benefits in normally aspirated engines, pays even bigger dividends when coupled with forced induction. Injecting gasoline directly into the combustion chamber cools the charge, increasing boost response, low and midrange torque production, and allowing for a high compression ratio and healthy boost due to better knock resistance.
The Mazdaspeed6 brings 15.6 psi to bear on 9.5:1 compression pistons, barely down from the 9.7:1 pistons found in the naturally aspirated engine. Mazda chose a Hitachi turbocharger using Borg Warner internals. This small unit contributes to the engine's excellent torque production and throttle response, and its small thermal mass shortens catalytic converter light-off time for improved cold-start emissions.
Although the engine redlines at 6700 rpm, it has little to give after 6000, where it feels like the little turbo simply runs out of headroom. It does, however, provide nearly 100 percent of its claimed 280 lb-ft of torque from just 2500 rpm, and remains flat until 5500 rpm, where the engine makes its peak horsepower figure of 274. Mazda claims a 0-to-60 sprint of 6.6 seconds, which is a bit pessimistic.
Interestingly, the intercooler sits directly on top of the valve cover. Mazda argues the cooler intake charge resulting from direct injection still meets efficiency targets with the intercooler in this location. It's no secret this positioning also significantly reduces flow through the core, makes packaging the engine easier and production cheaper.
But efforts were made to get air through the intercooler. A trick, two-piece ram-air duct supplies fresh high-pressure air at speed. The intercooler is housed in a box, which seals against molded plastic ductwork attached to the underside of the hood. Ram air nostrils draw air from under the leading edge of the hood.
The exhaust note is well tuned inside the cabin, but from the outside sounds like a linebacker exhaling through a cocktail straw-backpressure in D flat. Engineers hinted the engine endured extended bouts with more than 15.6 psi during testing with no ill results; a stiffer block, forged crankshaft and steel connecting rods offer proper credentials.
There is certainly power to be had from uncorking the exhaust. But once power figures start growing, the issue of whether the aftermarket can meet the challenge of a necessary bump in fueling, given the complexity of the ultrahigh-pressure direct-ignition fuel system, remains.
In a direct injection engine, the injectors can only fire during the compression stroke vs. constantly in an engine with port injection, which may explain some of the softness we felt after 6000 rpm as injectors struggled to inject more fuel in less time.
Our best advice is to use conventional auxiliary injectors in the manifold for added fueling once beyond the capacity of the DI system. Combine those with a front-mount intercooler and larger turbo and you'll have a legitimate powertrain capable of serious numbers.