Pure sports!The car that can be said may have only "FD" later and earlier.
That's why we started with "like"Out of print sports car update program. "
This time, the specifications of the new suspension kit for FD have been decided, so I will tell you about the development progress and the difference between "Street Sports Suspension Kit" and "Mass Production Suspension".

① Spring setting
The role of the spring in the suspension is to determine the ride height and maximum roll amount. Since the FD originally has no clearance (gap between the tire and fender) for mounting the snow chain, it is lower than other cars and has a low ride height in mass production.
Therefore, we set it to "-15mm" instead of our standard "-20 to -5mm".The spring constant is 110% of the mass production ratio, with the roll amount moderately suppressed, based on the concept of "more than mass production and less than tuning".

(XNUMX) "Damping ratio" that determines the damping force of the damper
Damping force is related to the speed of reaching the amount of roll determined by the spring.The balance between the spring and the damping force is called the "damping ratio" and is expressed in "%".
For example, "damping ratio 0%" does not apply damping force to the spring ... Extremely, it is running only with the spring.Therefore, once the spring contracts due to the protrusion, it will repeatedly vibrate up and down semi-permanently.On the other hand, a damping ratio of 100% is a state in which the expansion and contraction of the spring converges at one time. (This state is called the critical damping force and is calculated by the relationship of "sum of spring constants of 1 wheels x weight on spring")

The index of our damping ratio is "70%" for the initial roll area, "50%" for the ride comfort / protrusion area, and "30%" for the rough road area, regardless of the vehicle type.Specifically, when entering a curve, the moment when the roll starts is suppressed by 70% damping force against the spring, aiming for a gentle and wrinkled roll feeling, when passing through uneven manholes and areas that affect riding comfort. Reduced the damping ratio to 50%, and even lower it on rough roads.
Once the spring and damping force are determined, the desktop development is complete.However, this alone is not enough, so next we will evaluate the sensibility by installing it on the actual vehicle.

③ Kansei evaluation
In suspension development, once the spring specifications are determined, the damping force is determined based on the damping ratio.However, in the end, it is "how the driver feels", and in addition, whether "car lovers" feel that driving is fun and that they want to drive forever.

Even if the high-sensitivity sensor can digitize the roll feeling when entering a curve and the convergence when passing through a protrusion, it fits or does not fit because it is a human sensitivity evaluation.
In this area, there is no choice but to repeatedly change the damping force and spring of the damper and pursue it based on the experience value until the ride quality is as intended.

④ Specifications
FD is expected to deteriorate over time from its model year, and I think that many people have already installed the harmonic drive.
Therefore, this time, we will use a "mass production type damper" + "spring" + "Mazda genuine upper mount (for the final XNUMX type)" A'SSY kit to refresh the suspension as a whole.
The table shows the specifications of springs and dampers. "Sport degree" is determined by the spring constant, and "ride" such as roll feeling is created by damping force.

By the way, the damping ratios of the "new suspension kit" and "street sports suspension" are both prototypes and development of "70%, 50%, 30%", and are the result of tuning by evaluating the sensitivity of the actual vehicle.

The development concept of the new suspension kit is "more than mass production, less than tuning".We will revive the performance as a pure sport, enjoy the ride more than mass production, and have a long-term relationship as a partner ... I intend to finish it with such specifications.Release is scheduled for early March.If you are interested, please look forward to it.

Posted by A.Asanuma