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The TEIN FLEX Z coilover kit, part number VSM40-C1SA1-C, is designed for 1990-2005 Mazda MX-5 Miata NA and NB models. It combines 16-level damping adjustment, full-length ride-height adjustment, and front and rear pillowball upper mounts in a complete suspension package. With 7K front and 6K rear springs, this setup gives Miata owners more flexibility when setting ride height and tuning suspension response for street driving.
Key Features & Specifications:
Brand: TEIN
Series: FLEX Z
Product Type: Adjustable Coilover Suspension Kit
Part Number: VSM40-C1SA1-C
Fitment Years: 1990-2005
Vehicle: Mazda MX-5 Miata
Generations: NA / NB
Engine Applications: 1.6L and 1.8L 4-Cylinder
Drivetrain: Rear-Wheel Drive (RWD)
Damping Adjustment: 16 Levels, Front and Rear
Ride Height Adjustment: Full-Length Adjustable, Front and Rear
Damper Design: Twin-Tube
Front Upper Mounts: Pillowball
Rear Upper Mounts: Pillowball
Front Spring Rate: 7 kgf/mm (392 lbs/in)
Rear Spring Rate: 6 kgf/mm (336 lbs/in)
Front Spring Free Length: 175mm
Rear Spring Free Length: 150mm
Front Spring Inside Diameter: 70mm
Rear Spring Inside Diameter: 70mm
Front Spring Part Number: SW070-13175-C
Rear Spring Part Number: SA060-13150-C
EDFC Compatibility: Yes, optional components required
EDFC Motor Kit: EDK05-12120
Kit Coverage: Front and Rear Suspension
Fitment:
1990-1998 Mazda MX-5 Miata 1.6L / 1.8L RWD (NA)
1999-2005 Mazda MX-5 Miata 1.8L RWD (NB)
The Mazda Miata is a car where suspension changes are easy to notice, and TEIN FLEX Z gives you a useful range of adjustments without requiring a track-only setup. Whether you're refreshing an older NA or building an NB for weekend drives, these coilovers allow you to set ride height and damping to suit how you use the car.
The twin-tube dampers feature 16 levels of damping adjustment at the front and rear. You can keep the settings softer for ordinary roads or increase firmness when you want a more controlled response through corners.
FLEX Z also uses full-length ride-height adjustment, allowing the damper assembly length to be changed independently of spring preload. That provides more flexibility than a spring-seat-only lowering system when setting the car's stance.
Part VSM40-C1SA1-C covers the first two generations of the MX-5 Miata, from 1990 through 2005.
The kit pairs 7 kgf/mm front springs with 6 kgf/mm rear springs and uses pillowball upper mounts at both ends. These mounts create a firmer suspension connection than conventional rubber upper mounts.
TEIN specifies different recommended lowering settings for NA and NB applications. The figures also differ between the 1.6L and 1.8L NA models, so it's worth using the correct starting point for your car.
| Vehicle Application | Front | Rear |
|---|---|---|
| 1990-1998 Miata NA 1.6L | -1.0in (-25mm) | -1.0in (-25mm) |
| 1990-1998 Miata NA 1.8L | -1.2in (-30mm) | -1.2in (-30mm) |
| 1999-2005 Miata NB 1.8L | -1.4in (-35mm) | -1.4in (-35mm) |
| Vehicle Application | Front | Rear |
|---|---|---|
| Miata NA 1.6L | -1.4in to -0.6in | -1.4in to -0.6in |
| Miata NA 1.8L | -1.6in to -0.8in | -1.6in to -0.8in |
| Miata NB 1.8L | -1.8in to -1.0in | -1.8in to -1.0in |
| Vehicle Application | Front | Rear |
|---|---|---|
| Miata NA 1.6L | -2.6in to +1.1in | -3.2in to +0.3in |
| Miata NA 1.8L | -2.8in to +0.9in | -3.4in to +0.1in |
| Miata NB 1.8L | -3.0in to +0.5in | -3.6in to -0.1in |
Ride-height measurements are relative to factory suspension height. Maximum adjustment limits are not recommended everyday driving settings. Actual results depend on the vehicle's condition, available suspension travel, and wheel and tire clearance.
This FLEX Z kit supports TEIN's optional Electronic Damping Force Controller (EDFC) system with compatible separately purchased components.
EDFC Motor Kit: EDK05-12120
NA Miata Front EDFC Clearance: The left-side body connector may need to be relocated if it interferes with the motor.
NA Miata Rear EDFC Clearance: The spare tire must be relocated to provide clearance for the rear motor.
NB Miata Front EDFC Clearance: The left-side body connector may need to be relocated if it interferes with the motor.
NB Miata Rear EDFC Clearance: Rear interior trim may need to be cut or removed if it interferes with the motor.
Front Suspension Clearance: The front camber angle may need adjustment to avoid interference with the suspension arm.
Installation: Professional installation and a complete wheel alignment are recommended after fitting or adjusting the coilovers.
EDFC motors and controllers are optional accessories and are not included with the standard FLEX Z kit.
For Miata owners who want adjustable ride height and damping without moving to a dedicated competition suspension, FLEX Z offers a versatile setup for the NA and NB chassis.
