1996 Nissan 240sx Performance Parts

The Nissan 240SX, particularly the S14 chassis produced from 1995 to 1998 (often considered as a 1996 model for simplicity), remains a darling of the tuner world. Its rear-wheel-drive configuration, relatively lightweight chassis, and readily available aftermarket support make it an ideal platform for extracting impressive performance gains. This guide dives into common performance modifications for the 1996 240SX, explaining the theory behind each upgrade and the impact on the car's behavior.

Engine Performance Enhancements

The stock KA24DE engine in the 1996 240SX, while reliable, is often the first area targeted for improvement. Let's explore the most common modifications.

Intake System

Upgrading the intake system aims to improve airflow into the engine. The factory airbox is restrictive, limiting the amount of air the engine can draw in, especially at higher RPMs.

Cold Air Intake (CAI): A CAI typically replaces the factory airbox with a free-flowing air filter, often relocating it outside of the engine bay to draw in cooler air. Cooler air is denser, containing more oxygen per unit volume, leading to a more complete combustion. However, poorly designed CAIs can suffer from heat soak, negating their benefits. Placement is crucial. Look for CAIs that draw air from behind the bumper or fender well.
Short Ram Intake (SRI): An SRI places the air filter directly on the throttle body. While easier to install, SRIs often draw in hot air from the engine bay, potentially reducing performance. They can improve throttle response due to the shorter intake tract but generally offer less peak horsepower gain than a well-designed CAI.
Throttle Body Upgrade: Increasing the throttle body diameter allows more air to enter the engine at any given throttle position, improving throttle response and potentially increasing peak horsepower, especially when combined with other intake modifications. Careful consideration should be made with throttle body upgrades, as too large a throttle body can result in poor low-end torque and difficult drivability.

Exhaust System

The exhaust system's primary function is to expel exhaust gases from the engine. A restrictive exhaust system creates backpressure, hindering engine performance.

Headers: The exhaust manifold, or headers, are bolted directly to the engine's cylinder head. Aftermarket headers are typically designed to be less restrictive than the factory manifold, improving exhaust flow. Long tube headers are typically designed for maximizing top-end power, where as short tube headers improve low-end torque. When selecting headers, consider the primary tube diameter and collector design as they affect the scavenging effect, which helps draw exhaust gases out of the cylinders.
Catalytic Converter: The catalytic converter reduces harmful emissions but also restricts exhaust flow. A high-flow catalytic converter offers a compromise between emissions compliance and performance, allowing for better exhaust flow than the stock unit. A catalytic converter delete ("test pipe") is illegal in many regions and will cause the car to fail emissions testing, but provides the greatest flow improvement.
Cat-Back Exhaust System: A cat-back exhaust system replaces the exhaust system from the catalytic converter to the tailpipe. Aftermarket cat-back systems typically use larger diameter piping and less restrictive mufflers to improve exhaust flow. The muffler design significantly impacts the exhaust note. Chambered mufflers tend to be louder, while resonated mufflers are quieter.

Engine Management (ECU)

Modifying the engine's parameters requires adjustments to the engine control unit (ECU). The stock ECU has limited tuning capabilities, necessitating aftermarket solutions.

Piggyback ECUs: These units intercept and modify signals between the factory ECU and the engine. They offer some tuning flexibility but are generally less sophisticated than standalone ECUs. Examples include older Apexi SAFC units.
Standalone ECUs: These replace the factory ECU entirely, offering complete control over engine parameters, including fuel, ignition timing, and boost (if applicable). Standalone ECUs require skilled tuning but provide the greatest performance potential. Examples include AEM EMS and Haltech ECUs. Careful tuning is essential to prevent engine damage.
ECU Chipping/Reflashing: Involves modifying the program on the existing ECU to change parameters. This option is limited to specific ECU models and may not offer as much flexibility as standalone solutions.

Forced Induction (Turbocharging/Supercharging)

Forced induction significantly increases engine power by forcing more air into the cylinders. This is a complex and costly modification but offers substantial gains.

Turbocharging: Uses exhaust gas to spin a turbine, which compresses intake air. Turbocharger size and design significantly impact performance characteristics. Smaller turbos spool up quickly, providing good low-end torque, while larger turbos offer greater peak horsepower at higher RPMs. Intercooling is vital to cool the compressed air, increasing its density and preventing detonation.
Supercharging: Uses a mechanically driven compressor to force air into the engine. Superchargers offer instant boost response but typically provide less peak horsepower than turbos.
Internal Engine Upgrades: When considering forced induction, it is *highly* recommended to upgrade the engine internals, such as pistons, connecting rods, and head studs. The stock KA24DE internals are not designed to withstand the increased stress of forced induction, and failure can result in catastrophic engine damage.

Suspension and Handling

Improving the 240SX's handling enhances its cornering ability and overall driving experience.

Lowering Springs and Coilovers

Lowering the car's center of gravity improves handling by reducing body roll. Lowering springs offer a simple and relatively inexpensive way to lower the ride height, but they are typically paired with the stock shocks, which may not be adequately damped for the stiffer springs. Coilovers offer adjustable ride height and damping, allowing for fine-tuning of the suspension to suit specific driving conditions.

Sway Bars

Sway bars (also known as anti-roll bars) connect the suspension on opposite sides of the car. They resist body roll during cornering by transferring force from one side of the suspension to the other. Upgrading to thicker sway bars reduces body roll and improves handling. Adjustable sway bars allow for further fine-tuning of the car's handling balance. Increased front sway bar stiffness biases the car towards oversteer, while increased rear sway bar stiffness biases it towards understeer.

Bushings

The factory rubber bushings are designed to provide a comfortable ride, but they can flex excessively under load, reducing handling precision. Replacing the rubber bushings with polyurethane or spherical bearings improves handling by reducing suspension deflection. Polyurethane bushings offer a good balance of performance and comfort, while spherical bearings provide the most precise handling but can transmit more road noise and vibration.

Strut Tower Bars

Strut tower bars connect the strut towers on opposite sides of the car, increasing chassis rigidity. This reduces chassis flex during cornering, improving handling precision. Front and rear strut tower bars are available.

Braking System

Upgrading the braking system improves stopping power and reduces brake fade, especially during track driving.

Brake Pads: Upgrading to performance brake pads provides increased friction, resulting in shorter stopping distances. Different brake pad compounds are designed for different driving conditions. Street performance pads offer improved stopping power over stock pads while maintaining good cold bite. Track pads offer the highest friction but may require higher operating temperatures to perform optimally.
Brake Rotors: Upgrading to slotted or drilled brake rotors improves brake cooling and reduces brake fade. Slotted rotors help vent gasses produced by the brake pads, while drilled rotors dissipate heat more efficiently. However, drilled rotors can be prone to cracking under severe use.
Stainless Steel Brake Lines: Stainless steel brake lines replace the factory rubber brake lines. Rubber brake lines can expand under pressure, reducing braking performance. Stainless steel brake lines do not expand, providing a firmer brake pedal feel and more consistent braking performance.
Big Brake Kits: Big brake kits typically include larger brake rotors, multi-piston calipers, and performance brake pads. They offer significantly improved stopping power and brake fade resistance. Big brake kits are a more expensive upgrade but provide the most significant braking performance improvement.

Drivetrain

Upgrading the drivetrain enhances the car's ability to transmit power to the wheels efficiently.

Clutch: Upgrading to a stronger clutch is necessary when increasing engine power. A stronger clutch can handle the increased torque without slipping. Different clutch types are available, ranging from street performance clutches to racing clutches.
Lightweight Flywheel: Replacing the heavy factory flywheel with a lightweight flywheel improves engine response and acceleration. A lighter flywheel allows the engine to rev more freely. However, a too-light flywheel can make the car difficult to drive smoothly at low speeds.
Limited Slip Differential (LSD): An LSD improves traction by distributing power more evenly to the rear wheels. A LSD prevents wheel spin during acceleration, improving traction and cornering performance. Different LSD types are available, including clutch-type, Torsen-type, and viscous-type.
Final Drive Ratio: Changing the final drive ratio can improve acceleration or fuel economy. A shorter final drive ratio (higher number) improves acceleration, while a longer final drive ratio (lower number) improves fuel economy.

When choosing performance parts for your 1996 Nissan 240SX, consider your budget, driving style, and intended use. Research different brands and products thoroughly before making a purchase. Proper installation and tuning are essential to ensure optimal performance and prevent engine damage. Always prioritize safety and consult with a qualified mechanic if you are unsure about any aspect of the installation or tuning process.