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There's a natural tendency for curb weight to increase when we try to meet growing market demands. Realizing that this is contrary to the Jinba Ittai goal and that extra weight would have a dramatically negative influence on driving, cornering, and braking performance, Mazda engineers made every gram count. (In the English measurement system used in the U.S. and elsewhere, one pound equals 454 grams.) Their "gram strategy" assessed weight in the smallest possible increments and carefully scrutinized weight-trimming opportunities. Other weight-saving tactics were employed as well. Advanced technology was applied where practical to achieve a light and rigid unibody design using materials that offered higher strength and lighter weight.

In its final form, the new Mazda MX-5 is more powerful, more capable, more comfortable, and more useful. It offers several new features and further improves occupant protection from collision injury. Yet, thanks to Kansei Engineering efforts, curb weight has only increased by approximately 10 kg (22 pounds).

While saving weight is a top priority for achieving Jinba Ittai, other concerns were the stiffness of the unibody structure, the height of the car's centre of gravity, 50:50 weight distribution and the vehicle's moment of inertia about the vertical (yaw) axis. (A lower yaw moment of inertia quickens the vehicle's responsiveness to the driver's steering commands.) Each of these parameters strongly influenced the new Mazda MX-5's overall fun-to-drive characteristics.

A stiff body structure is an essential ingredient in the feeling of oneness between the driver and the car. Thanks to shrewd analysis and the application of advanced materials such as ultra-high-tension steel, the new unibody delivers an increase of 22 percent for flexural stiffness and 47 percent for torsional rigidity compared to the previous-generation Mazda MX-5. And moving the engine rearward by 135 mm (5.3 inches) was a major step towards balancing front-to-rear weight distribution and reducing the yaw moment of inertia.