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ENGINES
A spirited engine and a wieldy transmission constitute the heart of any sports car. Two new MZR family engines-a 2.0-litre for all global markets and an additional 1.8-litre for Europe-power the all-new Mazda MX-5. These are light and compact and feature chain-driven double overhead camshafts, four valves per cylinder, variable intake valve timing, electronically controlled port fuel injection, and coil-on-plug ignition. The block, head, and oil pan are cast aluminium, while cast iron liners provide a durable bore surface.
Both engines share a 10.8:1 compression ratio and an 83.1 mm stroke that is slightly shorter than the length of the piston's travel in the previous 1.8-litre engine. The bore in the 2.0-litre engine is 87.5 mm versus 83.0 mm for the 1.8-litre version.
Final output for each engine will be confirmed as the vehicles go on sale in key markets. Output for the 1.8-litre is targeted to be 93 kW/ 126 PS at 6,500 rpm with maximum torque of 167 Nm (17.0 kg-m) at 4,500 rpm. The 2.0-litre European model is targeted to be 118 kW/160 PS at 6,700 rpm with peak torque of an estimated 188 Nm (19.2kg-m) at 5,000 rpm. Engine output will differ depending on local requirements.
Throughout the development process, work focused on what Mazda engineers called "response" and "expansion feel." A lighter flywheel, a quick response, an electric throttle and a stiff drive shaft all helped realize the responsive direct feel of the new Mazda MX-5. The new Mazda MX-5's engine's torque curve is held nearly level at high rpm by major reductions in intake and exhaust restriction. The result is an engine champing at the bit as it revs enthusiastically past the point of maximum torque to the redline, with superior response and direct feel.
Additional attention was paid to intake and exhaust passages. A 57 percent reduction in intake restriction was achieved with a large, open intake pipe and smooth layout. On the exhaust side, the pressure loss of the system was reduced by 40 percent thanks to the use of a high-volume muffler and a dual tail pipe.
In tuning the Mazda MX-5's engine sound, a smooth, harmonic note was realized that increases with throttle opening. Above 5,000 rpm, this becomes powerfully resonant, consistent with the spirited charge for the 6,700 rpm redline. A throaty 500 Hz sound through the mid-range reinforces the Mazda MX-5's feeling of nimble responsiveness.
TRANSMISSIONS
Mazda's newly-developed six-speed manual transmission is available in all markets. Five-speed manual and advanced six-speed automatic, which can be manually controlled by the shift lever and by steering-wheel-mounted paddles, are also lined up (depending on market).
Sports car enthusiasts reap a special pleasure from changing gears by a quick flick of the wrist. To enhance this aspect of the Mazda MX-5 character, the shift lever's movement was engineered for ultra low effort and a very short stroke. Triple-cone synchronizers for the first four gears help reduce engagement forces. In the interests of efficiency, the 3rd and 4th gear synchros are located on the counter shaft. The shift rod is supported by low-friction bushings and lever motion is directed by a guide plate.
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