The factory DISI turbo exhibits good initial response. Boost hits hard with instant torque at 3000rpm, but falls off quickly from 5500rpm to redline. To balance the torque between getting out of corners and diminishing high-rev power on this fast track, short-shifting is necessary in the higher gears to achieve even quicker straightaway speeds. The six-speed transmission's closer gear ratios hurt the Mazdaspeed3 at Buttonwillow (as opposed to the five-speed Mazda3) since additional time-consuming upshifts are required right before the braking zones. Slightly taller gears would eliminate two upshifts and subsequent downshifts per lap. In second gear, the revs are too high in the all-important Button Hook hairpin, forcing an upshift before track-out. Although the engine has a lot of low-down torque, third gear is too tall to pull uphill out of that tight corner.
The torque would have been more useful if our test car's factory-equipped Tochigi-Fuji limited-slip differential hadn't been so heavily abused in the past. This levels the playing field with the other open-diff-equipped competition, since more precise throttle modulation is needed to avoid spinning the inside wheel. Still, although the LSD doesn't lock aggressively, it puts significantly more power to the ground than an open diff and this helps get out of the hairpin quicker than the other two cars.
Wider and lower-profile factory Bridgestone RE050A tires generate more grip, allowing for higher cornering speeds and better turn-in feel than the all-season Goodyears on the base Mazda3. In contrast to that car's suspension, the Mazdaspeed3's lower stance, combined with stiffer springs and dampers, result in less body roll, making it feel much more at home on the track-despite its hefty 3153-pound weight.
Chassis reinforcements are also noticeable, giving a more solid feel and more neutral mid-corner rotation. On early laps, high-speed braking points are similar to the Mazda3 on account of the larger brakes, added grip and more refined suspension damping, despite the 10mph difference. But the higher speeds mean more brake abuse and the system boils the stock fluid after two laps. Ultimately, the car needs longer braking distances, even on its fastest lap, to compensate for the extra speed. Fresh pads and fluid would increase braking performance significantly; we've seen stock Mazdaspeed3 brakes endure lap after lap, even on brutal tracks like Laguna Seca.
This Mazdaspeed3's heavy testing history also showed in terms of tire grip and degraded dampers. The left front tire's outer tread blocks were so worn from all the previous track time on configuration 13 that the mid-corner speeds through the section seven high-speed Talladega corner were lower than even the stock Mazda3 (on all-season tires, remember). In a last-ditch effort to squeeze out a better time, the front tires are swapped from right to left. This increases overall speed through Talladega, but at the cost of speeds in the left-hand corners of turns two and eleven (Sunrise and Sunset), a net gain of one second.
Tri-Point Engineering Turbocharged Mazda3Bets were against the turbocharged Tri-Point Mazda 3's ability to beat the stock Madzaspeed3. Even with the advantage of slightly wider (but harder) Bridgestone Potenza UHP RE760 Sport summer tires (mounted on 18x8 Tenzo-R DC-5 wheels), a larger Tri-Point rear anti-roll bar, heavy duty clutch and Koni/Eibach sport suspension, we didn't think these entry-level bolt-ons could make up for the fancy traction advantages on the factory car.