The second aspect of the Mazdaspeed equation is best-in-class dynamic performance. To figure out exactly what that means, Mazdaspeed benchmarked a wide range of cars globally, including the Dodge Neon SRT-4, Acura RSX Type-S, Subaru WRX, VW GTI (MkIV), and Ford Focus RS. In addition, "stretch targets" like the Mitsubishi Lancer Evo and Subaru WRX STI were evaluated to see how the Mazdaspeed3 fairs against the very best in the sport compact universe. The Mazdaspeed3 was not tested against either the latest-generation Honda Civic Si or VW GTI, but Kaneko feels the substantial engine, chassis and suspension improvements make his 3 tough to beat.
Along with extra bracing and other reinforcements integrated into the chassis and body panels on the production line, the front strut towers were heavily fortified to improve torsional rigidity. A new damper and spring package lowers the car by 10mm, compared to stock. Aggressive valve damping and higher spring rates work in combination with the larger anti-roll bars, reinforced lateral links and higher bushing durometers to significantly reduce body roll while providing sharper turn-in and steering feel.
The third and most critical parameter involves upgrading the powertrain. Again, to be considered a Mazdaspeed vehicle, the 3 had to be the class leader in terms of useable power and torque. So it receives the same turbocharged inline-four MZR engine found in the Mazdaspeed6 and new CX-7 SUV. This advanced engine is Mazda's own flagship design based on a turbocharged 16-valve, DOHC 2.3-liter with integrated direct injected spark ignition (DISI) architecture. A heavily modified turbo MZR engine, featuring a similar DISI design, powers current NHRA Sport Compact ProFWD Champion Ed Bergenholtz's 1400-plus hp Mazda6.
DISI is the latest technology to hit the automotive industry. Right now, only Mazda and VW/Audi sell direct injection gasoline engines, which have a couple of distinct advantages over traditional port injection engines.
Port injection mixes fuel and air in the intake runners at about 35 to 60psi, while Mazda DISI engines mix a pure charge of air with fuel injected directly into the cylinder at over 1600psi. The higher pressure creates a denser, more homogeneous air/fuel mixture and cleaner, more powerful burn. Spraying fuel directly into the cylinder also provides a cooling effect, which results in greater combustion efficiency and knock deterrance-Mazda estimates a three to five per cent improvement in fuel economy over port injection engines.
As high tech as DISI is, it is not the reason the Mazdaspeed3 has so much power and torque. Credit the Warner-Hitachi K04 turbo; the same unit found in the Mazdaspeed6. For a stock turbo, it has a lot of trick features, including a compressor stage supported by a full-floating, journal-bearing, water-cooled center section. Power balance is supported by a 79 trim 50mm turbine stage with an Inconel shaft-wheel mated to a 16.5mm A/R Niresist iron turbine housing. Maximum turbine speed is over 165,000rpm with a peak exhaust gas temperature in excess of 990 degrees Celsius.
Mazda wouldn't tell us the exactly how much boost is in the Mazdaspeed3, but given that the engine and turbo are the same as those found in the 274bhp Mazdaspeed6, we're guessing the manifold pressure is similar as well - roughly 16psi. Whatever it is, it's helping the Mazdaspeed3 make an impressive amount of power and torque - 263bhp at 5500rpm and 280ft-lb at 3000rpm. To put that in perspective, the last really fast factory front-wheel-drive turbo foor-door was the 2004 Dodge Neon SRT-4, which only made 230bhp and 250lb-ft of torque.
"The hard part wasn't getting the power," says Kaneko, "but getting the power to the ground. The Mazdaspeed3 has slightly lower power output in comparison to the Mazdaspeed6, primarily because we had to balance raw power output versus dynamic driveability."