Nuts and Bolts While the 2006 Mazda MX-5 Miata’s powerplant displacement remains constant, the output varies slightly depending on which gearbox is chosen. With a manual, the motor makes 170 horsepower. With the optional automatic, the rating drops to 166 horsepower.

While the 2006 Mazda MX-5 Miata’s powerplant displacement remains constant, the output varies slightly depending on which gearbox is chosen. With either the five- or six-speed manual, the 2.0-liter inline-four yields 170 horsepower at 6,700 rpm. Going with the automatic six-speed lowers the power rating a tad, summoning only 166 horsepower. Despite the slightly lower power rating, we were thoroughly impressed with this automatic gearbox and its crisp power, especially when shifting gears manually. All versions of this engine develop 140 lb.-ft. of torque at 5,000 rpm and redline at 7,000 rpm. In contrast, last year’s 1.8-liter mill made only 142 horsepower and 125 lb.-ft. of torque.

Cast aluminum heads and block, dual overhead cams, and variable intake valve timing contribute to the little four’s performance. While this engine pales in comparison to the 240-horse, 2.2-liter four-cylinder that Honda uses in its S2000 roadster, remember that the Honda starts at $33,150. A better match price-wise is the Mini Cooper convertible, which delivers 115 horsepower from its naturally aspirated 1.6-liter four or 168 horsepower in the supercharged Cooper S. Prices for the Mini begin close to $21,500 for the Cooper convertible and $24,950 for the supercharged S, although the Mini is more of a sprightly four-seat runabout and is not a true roadster.

The three Miata transmissions all have a final drive ratio of 4.100:1. Each varies in gearing, with the five-speed manual and six-speed automatic hitting 1:1 ratios in fourth gear and the six-speed manual matching this ratio in fifth gear. The six-speed automatic achieves a lofty 0.582:1 in sixth gear. Paddle shifting is available as an option on six-speed automatic versions of the Touring, Sport and Grand Touring models.

All Miatas deliver power to the rear wheels and come with an independent multi-link rear suspension setup that complements a double wishbone front design. Aluminum is used extensively to help reduce unsprung weight for better handling. Stabilizer bars and gas-filled monotube dampers are standard, with upgraded Bilsteins shocks optional. Rack-and-pinion steering requires just 2.6 turns lock-to-lock thanks to a 15.0:1 steering ratio. Four-wheel-disc brakes with ABS include 11.4-inch ventilated front rotors and 11-inch solid rear rotors, the fronts having grown by almost one inch.