240sx High-performance Parts: The Ultimate Guide To Upgrades

Alright, let's talk about building a serious 240SX. Whether you're aiming for drifting, track days, or just a potent street machine, the S-chassis offers a fantastic platform. But extracting real performance requires more than just throwing parts at it. This guide is about making smart, informed choices to get the most out of your build.

Engine Upgrades: Unleashing the Power

The Heart of the Beast: SR20DET vs. KA24DE

First, let's address the elephant in the room: engine swaps. The SR20DET is the gold standard for a reason. It's a 2.0L turbocharged engine known for its robust internals and readily available aftermarket support. The KA24DE, the original engine in many 240SXs, is a capable engine, but it's limited in its naturally aspirated form. Turbocharging it is an option, but it requires careful planning and investment in forged internals for long-term reliability.

If you’re sticking with the KA24DE and want to squeeze more power, consider the following:

High-Compression Pistons: Bumping up the compression ratio will significantly increase power output, especially in the midrange. Be mindful of fuel requirements; you’ll likely need to run premium fuel.
Performance Camshafts: Upgrade to a more aggressive camshaft profile to improve airflow at higher RPMs. This changes the valve lift and duration, essentially controlling how long and how far the valves open. Professional tuning is a must after this upgrade.
Port and Polish the Cylinder Head: Smoothing out the intake and exhaust ports in the cylinder head reduces flow restriction, allowing for better airflow and more power. This is a delicate process best left to experienced machinists.

However, for serious power goals, the SR20DET is the more logical choice. Here’s what you should consider when upgrading it:

Turbocharger Upgrade: The factory turbo is good for moderate power, but a larger turbo is essential for higher horsepower figures. Pay attention to A/R ratio (affecting spool-up time) and the turbo's horsepower rating. Garrett, BorgWarner, and Precision Turbo are popular choices.
Intercooler: An upgraded intercooler is crucial for cooling the intake air charge, reducing the risk of detonation and increasing power. Front Mount Intercoolers (FMICs) are generally the most effective.
Fuel System: As you increase boost, you need to supply more fuel. Upgrading to larger fuel injectors, a high-flow fuel pump, and an adjustable fuel pressure regulator is critical to prevent leaning out.
Engine Management System (EMS): The factory ECU is limited in its capabilities. Switching to a standalone EMS like AEM, Haltech, or Link allows for precise control over fuel, ignition timing, and other parameters. This is essential for maximizing performance and ensuring engine safety. Understanding ignition timing advance and fuel maps will be key to tuning.

Internal Fortification: Built to Last

Regardless of whether you choose to stick with the KA or swap to an SR, forged internals are crucial for high-power applications. Forged pistons and connecting rods are significantly stronger than their cast counterparts, allowing them to withstand the higher stresses associated with increased boost and horsepower. Also consider ARP head studs to ensure proper head sealing under high cylinder pressures.

A blown engine is an expensive learning experience. Investing in reliable internals is always a wise decision.

Drivetrain: Getting the Power to the Ground

More power means more stress on the drivetrain. The stock components are often a weak point, especially with an SR20DET.

Clutch and Flywheel

An upgraded clutch is a must-have. Choose a clutch that is rated for more torque than your engine produces. Options include:

Organic Clutch: Good for street use, offering smooth engagement and relatively quiet operation. However, they have a lower torque capacity.
Ceramic Clutch: Offer a higher torque capacity but can be grabby and less forgiving for daily driving.
Multi-Disc Clutch: Provide the highest torque capacity and are often used in high-power applications. Can be expensive and require more maintenance.

A lightweight flywheel can improve engine response and acceleration. However, excessively lightweight flywheels can make the engine stall more easily.

Transmission

The factory transmission can handle moderate power levels, but upgrading to a stronger transmission is a good idea for high-horsepower builds. Popular options include:

Nissan Z32 Transmission: A robust 5-speed transmission that is a popular upgrade for the SR20DET.
BMW E46 M3 Transmission: Another strong 6-speed option that requires an adapter plate.

Differential and Axles

An upgraded limited-slip differential (LSD) is essential for improving traction and handling. LSDs distribute torque to both rear wheels, preventing wheel spin and improving acceleration out of corners. Common types of LSDs include:

Clutch-Type LSD: Provides aggressive lockup and is suitable for drifting and track use. Can be noisy and require more maintenance.
Torsen LSD: Offers smoother and more progressive lockup, making it suitable for street and track use.
Viscous LSD: Provides a more subtle lockup and is generally not recommended for high-performance applications.

Upgraded axles are also crucial for preventing breakage under high stress. Choose axles that are rated for more torque than your engine produces.

Suspension and Handling: Mastering the Corners

Improving the 240SX's handling is just as important as increasing its power. A well-sorted suspension will make the car more predictable and enjoyable to drive.

Coilovers

Coilovers allow you to adjust the ride height and damping characteristics of your suspension. Look for coilovers with adjustable dampening (rebound and compression) for optimal performance. Spring rates should be chosen based on your intended use (street, track, or drift).

Sway Bars

Upgraded sway bars (also known as anti-roll bars) reduce body roll during cornering, improving handling and stability. Adjustable sway bars allow you to fine-tune the balance of the car.

Control Arms

Aftermarket control arms offer improved adjustability and strength. Adjustable control arms allow you to correct suspension geometry after lowering the car and fine-tune camber and caster settings. Camber refers to the angle of the wheel relative to the vertical axis, while caster refers to the angle of the steering axis.

Bushings

Replacing the old, worn-out rubber bushings with polyurethane or spherical bearings improves suspension response and reduces deflection. Polyurethane bushings offer a good balance of performance and durability, while spherical bearings provide the most precise suspension movement but can be noisy and require more maintenance.

Braking System: Stopping Power

More power requires more stopping power. Upgrading the brakes is crucial for safety and performance.

Brake Rotors and Pads

Upgrading to larger brake rotors and more aggressive brake pads will significantly improve braking performance. Slotted or drilled rotors can help to dissipate heat and improve brake bite. Choose brake pads that are appropriate for your intended use. Track-focused pads typically offer higher friction at higher temperatures but may be noisy and produce more brake dust.

Brake Calipers

Upgrading to multi-piston calipers provides more clamping force and improved brake feel. Common upgrades include brakes from the Nissan 300ZX (Z32) or aftermarket big brake kits from companies like Wilwood or Brembo.

Brake Lines

Stainless steel brake lines improve brake pedal feel by reducing expansion under pressure. They are a relatively inexpensive upgrade that can make a noticeable difference.

Electronics and Monitoring: Keeping Everything in Check

Monitoring your engine's vitals is critical for preventing problems and maximizing performance.

Gauges

Install gauges to monitor important parameters like boost pressure, oil pressure, oil temperature, and water temperature. This will allow you to identify potential problems before they cause serious damage.

Wideband O2 Sensor

A wideband O2 sensor provides accurate air/fuel ratio readings, which are essential for tuning the engine. This information is used by the EMS to optimize fuel delivery and prevent leaning out.

Boost Controller

An electronic boost controller allows you to precisely control the boost pressure of your turbocharger. This can be used to increase power and improve throttle response.

Final Thoughts

Building a high-performance 240SX is a journey, not a destination. Take your time, do your research, and choose the right parts for your goals and budget. Remember that proper installation and tuning are just as important as the parts themselves. Don't be afraid to ask for help from experienced mechanics and tuners. With careful planning and execution, you can transform your 240SX into a truly impressive machine. Good luck and happy wrenching!