The second year of the NB-generation Mazda Miata project, spanning from March 2022 to February 2023, represents a pivotal phase in the vehicle’s transition from a standard road-going convertible to a purpose-built track and autocross competitor. This period was characterized by a systematic approach to performance optimization, involving aerodynamic enhancements, powertrain calibration, and a rigorous schedule of competitive events. The evolution of the vehicle—a 1999–2000 NB1 model—serves as a case study in grassroots motorsports development, emphasizing the synergy between mechanical upgrades and driver skill acquisition.

Executive Summary of Technical Progress

The primary objective for the second year of ownership was to reduce lap times through a combination of increased engine output, improved chassis dynamics, and aerodynamic stability. Data collected throughout the year indicates a substantial performance delta. At Raceway Park of the Midlands (RPM), the project’s primary testing ground, the vehicle achieved a cumulative lap time improvement of 11.29 seconds over a seven-month period. This advancement was supported by a 18.2% increase in wheel horsepower, achieved through the integration of a programmable electronic control unit (ECU) and high-octane fuel conversion.

Chronological Development and Track Performance

Spring 2022: Establishing the Baseline

The driving season commenced in March 2022 at Raceway Park of the Midlands. Initial sessions focused on establishing a performance baseline following the winter modifications of the previous year. The driver participated in eight total track days at this facility, utilizing its notoriously abrasive and undulating surface to test the durability of the suspension and tire setups.

In April, the project expanded its geographic reach to Motorsports Park Hastings (MPH). This facility provided a stark contrast to RPM, featuring a recently resurfaced asphalt track and superior paddock infrastructure. The smooth surface at Hastings allowed for a more nuanced evaluation of the vehicle’s handling characteristics at high speeds, though the vehicle’s setup remained largely identical to the March configuration. The comparison between the two tracks highlighted the necessity for a versatile suspension tune capable of handling both rough, patched surfaces and high-grip, smooth asphalt.

Summer 2022: Logistics, Power, and Multi-Discipline Testing

By May 2022, the focus shifted toward structural and logistical improvements. The aging vinyl soft top, which had suffered from cracks and temporary patches, was replaced with a premium Robbins canvas top featuring a zippered glass window. The installation was performed using a secondary frame sourced from a salvage yard, allowing for a modular swap. This upgrade improved the vehicle’s weather sealing and aesthetic profile while offering better material flexibility in cold weather.

In June, the project addressed the Miata’s inherent lack of cargo space by developing a custom tire trailer. Built on a 40×48 Northern Tool chassis with an extended plywood deck, the trailer allowed for the transport of a dedicated set of track tires, tools, fuel jugs, and paddock supplies. Weighing approximately 700 lbs when fully loaded, the trailer demonstrated the Miata’s surprising utility as a tow vehicle, covering over 1,000 miles during the season without mechanical incident.

The month of July saw a significant milestone in powertrain development. Following the installation of a "squaretop" intake manifold and a Megasquirt ECU tuned for E85 ethanol fuel, the vehicle was tested on a dynamometer. The results showed an increase from 115 wheel-horsepower (whp) and 106 lb-ft of torque in late 2021 to 136 whp and 119 lb-ft of torque. This 21-hp gain provided a critical advantage on longer straights and during corner exits.

In August, the vehicle was campaigned at Heartland Motorsports Park in Topeka. This track, known for its significant elevation changes and high-speed banked sections, challenged the driver’s confidence and the vehicle’s high-speed stability. The month of August also marked the project’s first foray into SCCA Rallycross at I-80 Speedway. This off-road experience emphasized car control in low-traction environments, though it resulted in minor cosmetic damage to the front air dam.

Autumn 2022: Competition and Risk Management

September and October were dedicated to the Sports Car Club of America (SCCA) Nebraska Region’s autocross season. Held at the same site as the SCCA Solo Nationals, these events provided long, complex courses. The driver’s performance metrics showed a steep learning curve, moving from the bottom 8% of the field at the start of the year to the top 50% by the season’s conclusion.

However, the pursuit of performance limits resulted in a significant incident on October 29. During the final track day of the season at RPM, the vehicle experienced a high-speed understeer event through Turn 11 after the driver attempted to correct a slide in Turn 10. The vehicle departed the track and impacted a tire wall at approximately 60 mph.

The impact resulted in damage to the hood, front bumper, left fender, and headlight. Due to the energy-absorbing properties of the tire wall and the Miata’s structural integrity, no mechanical or frame damage occurred, and the driver was able to drive the vehicle home. This event underscored the importance of safety margins and the inherent risks of pushing a vehicle to its absolute limit in a track environment.

Winter Reconstruction and Technical Refinement

November 2022: Rapid Repair and Cosmetic Restoration

The recovery from the October incident was swift. Within one week, the fender was replaced, and the bumper was reshaped, allowing the vehicle to compete in a scheduled autocross event. By the end of November, a replacement hood and bumper were installed. The vehicle’s yellow vinyl wrap proved to be a cost-effective solution for cosmetic consistency, as re-wrapping the new panels was significantly cheaper than professional paint matching. The vehicle was officially placed into winter storage following the Thanksgiving holiday.

December 2022: Suspension Kinematics

During the December teardown, the focus turned to the chassis. The previous year’s rubber bushings were replaced with A1 Ground Control Nylatron bushings in new control arms. Nylatron, a self-lubricating thermoplastic, was selected over traditional polyurethane to minimize binding and friction within the suspension pivots. Additionally, Paco Motorsports adjustable rear upper control arms were installed to allow for more precise alignment settings. While these modifications increased Noise, Vibration, and Harshness (NVH) levels, they provided a more direct and predictable steering response.

January 2023: Powertrain Integrity and Sourcing

The engine was partially dismantled in January to address a persistent rear main seal leak. During this service, the owner performed a "while-you-are-in-there" overhaul, which included:

• Installation of a Supermiata sport clutch and lightweight flywheel.
• Replacement of the oil pan gasket and front main seal.
• Installation of a new water pump and timing belt.
• Upgrading to a 37mm aluminum radiator and a coolant reroute kit to improve thermal management.

Simultaneously, the project secured a BP6D Variable Valve Timing (VVT) engine and a six-speed manual transmission from a later NB2 model, providing a future path for powertrain evolution.

The Integration of Advanced Aerodynamics

In February 2023, the project reached its current state with the installation of a Nine Lives Racing medium downforce aero kit. This package included a frame-mounted front splitter and a single-element aluminum rear wing. The aerodynamic upgrades were designed to counteract the Miata’s natural lift at high speeds, a phenomenon that had caused instability during the previous season’s high-speed sessions.

Initial street testing indicated a significant shift in the vehicle’s behavior. The increased downforce provided a more "planted" sensation at highway speeds without a perceptible penalty in acceleration. The kit was selected specifically to comply with SCCA XS-B class rules, ensuring the vehicle remains legal for competitive autocross and time trial events.

Impact and Broader Implications

The two-year journey of this NB Miata illustrates the viability of the platform as a premier choice for grassroots motorsports. Despite the age of the chassis, the availability of aftermarket support and the simplicity of the mechanical design allow for significant performance gains on a modest budget.

From a driver development perspective, the project highlights that mechanical upgrades must be paired with seat time. The 11.29-second improvement at RPM was as much a result of the driver learning the nuances of weight transfer and cornering lines as it was a result of the 21-horsepower increase. The project also serves as a reminder of the resilience of the Miata community, where parts availability and shared technical knowledge enable owners to recover from track incidents that might otherwise end a project.

As the car enters its third year, it stands as a highly modified, aerodynamically optimized machine, ready to challenge more modern and expensive sports cars on the track. The transition from a "budget roadster" to a "technical project" is complete, setting the stage for a competitive 2023 season.