A Directory Of Oem And Aftermarket Engine Components For The Nissan 240sx

The Nissan 240SX, a darling of the import tuner scene, offers a fantastic platform for engine modification and upgrades. Its original engine, typically the KA24DE or SR20DET, is known for its robustness and responsiveness, making it a solid foundation. However, pushing these engines beyond their factory specifications requires careful consideration of components. This guide provides an overview of available OEM and aftermarket engine components, offering insights into their function and potential benefits. We'll explore options for both naturally aspirated (NA) and turbocharged builds, delving into the key components and their impact on performance.

Engine Blocks and Internals

The engine block is the foundation of any engine build. For KA24DE owners, the original block is generally sufficient for moderate power gains. However, for those seeking substantial increases, aftermarket blocks offer improved strength and rigidity. These blocks are often made from stronger materials and feature thicker cylinder walls, reducing the risk of cracking or warping under high boost pressures. The SR20DET community has access to both factory SR20 blocks and aftermarket options from brands like Tomei and Darton. These aftermarket SR20 blocks are highly sought after for extreme horsepower builds, offering superior strength and the possibility of larger bore sizes.

Pistons

Pistons are a critical component for any performance build. OEM pistons are often cast, which is adequate for stock power levels. Aftermarket pistons are typically forged, offering significantly greater strength and resistance to heat. This is crucial for turbocharging or high-compression NA builds. Forged pistons allow for higher cylinder pressures without the risk of piston failure. Factors to consider when choosing pistons include: compression ratio (critical for NA builds and turbo tuning), material (typically 4032 or 2618 aluminum alloys), and weight (lighter pistons improve engine responsiveness). Brands like Wiseco, CP Pistons, and JE Pistons are popular choices for 240SX engines.

Connecting Rods

Connecting rods link the pistons to the crankshaft. Like pistons, OEM connecting rods are often adequate for stock power levels, but forged rods are essential for high-performance builds. Forged rods are significantly stronger and more resistant to bending or breaking under high stress. They are also often lighter than OEM rods, reducing reciprocating mass and improving engine response. H-beam and I-beam designs are common, with H-beam rods generally being stronger but slightly heavier. ARP rod bolts are considered a must-have upgrade when installing aftermarket connecting rods, providing a secure and reliable connection. Manley, Eagle, and Brian Crower (BC) are well-known manufacturers of forged connecting rods for the 240SX.

Crankshaft

The crankshaft converts the linear motion of the pistons into rotational motion. The OEM crankshaft in both the KA24DE and SR20DET is typically strong enough for moderate power increases. However, for extreme builds or those seeking the ultimate in reliability, aftermarket crankshafts offer advantages. Forged crankshafts are significantly stronger than cast or billet crankshafts. They can withstand higher torsional loads and are less prone to failure under extreme conditions. Balanced and knife-edged crankshafts are also available, which reduce weight and improve engine response. Tomei and Brian Crower offer high-quality crankshafts for the SR20DET. The KA24DE aftermarket crankshaft options are relatively limited compared to the SR20DET.

Cylinder Head and Valvetrain

The cylinder head plays a crucial role in engine performance, controlling airflow into and out of the combustion chamber. The SR20DET benefits from a robust aftermarket cylinder head scene. The KA24DE has limited aftermarket support, but porting and polishing the OEM head can yield significant improvements.

Camshafts

Camshafts control the timing and duration of valve opening and closing, significantly impacting engine performance. Aftermarket camshafts offer various profiles to optimize performance for different driving styles and power bands. Higher lift and longer duration camshafts generally improve top-end power but can sacrifice low-end torque. Adjustable cam gears allow for fine-tuning of cam timing, maximizing performance. Consider the intended use of the vehicle (street, track, drift) when selecting camshafts. Common brands include Tomei, Brian Crower, and Kelford Cams.

Valves and Valve Springs

Upgrading valves and valve springs is essential for high-RPM or high-boost applications. Aftermarket valves are often made from lighter and stronger materials, such as stainless steel or titanium. Lighter valves reduce valve float, allowing the engine to rev higher without losing power. Upgraded valve springs are necessary to control the heavier valves and prevent valve float at high RPM. Dual valve springs are often used for extreme applications, providing increased spring pressure. Ferrea and Supertech are popular brands for valves and valve springs.

Cylinder Head Porting and Polishing

Porting and polishing the cylinder head involves reshaping the intake and exhaust ports to improve airflow. Porting increases the volume of the ports, while polishing reduces friction. This can significantly improve engine performance, especially when combined with other upgrades such as camshafts and valves. Professional porting and polishing are recommended for optimal results. Be wary of over-porting, as this can actually decrease airflow velocity and reduce performance.

Forced Induction Components (Turbochargers)

For 240SX owners looking for significant power gains, turbocharging is a popular option. The SR20DET came turbocharged from the factory, making it a natural candidate for further turbo upgrades. The KA24DE can also be successfully turbocharged, but requires more extensive modifications.

Turbocharger Selection

Choosing the right turbocharger is crucial for achieving the desired performance. Factors to consider include: power goals, engine displacement, and driving style. Smaller turbochargers spool up quickly, providing good low-end torque, while larger turbochargers offer higher peak power but may suffer from turbo lag. Ball-bearing turbochargers offer improved spool-up and response compared to journal-bearing turbochargers. Garrett, BorgWarner, and Precision Turbo are well-respected turbocharger manufacturers. Consider the A/R (area/radius) ratio of the turbine housing, which affects spool-up characteristics. A smaller A/R will spool faster, while a larger A/R will allow for higher top-end flow.

Intercooler

An intercooler cools the compressed air from the turbocharger before it enters the engine. This increases air density and reduces the risk of detonation, allowing for higher boost pressures and more power. Front-mount intercoolers (FMICs) are a popular choice for 240SXs, offering excellent cooling efficiency. Core size and fin density are important factors to consider when choosing an intercooler. Larger cores provide better cooling, but can also increase pressure drop. Mishimoto, GReddy, and HKS are well-known intercooler manufacturers.

Wastegate and Blow-Off Valve (BOV)

A wastegate controls the maximum boost pressure by bypassing exhaust gas around the turbine wheel. An external wastegate offers better boost control compared to an internal wastegate. A blow-off valve (BOV) releases excess pressure in the intake system when the throttle is closed, preventing compressor surge and protecting the turbocharger. Recirculating BOVs are typically used on cars with mass airflow sensors (MAF) to maintain proper air-fuel ratios. Tial, Turbosmart, and HKS are popular manufacturers of wastegates and BOVs.

Fuel System

Upgrading the fuel system is essential for any performance build, especially when adding a turbocharger. Insufficient fuel delivery can lead to lean conditions and engine damage.

Fuel Injectors

Larger fuel injectors are necessary to deliver the increased fuel volume required by a high-performance engine. Injector size is measured in cc/min (cubic centimeters per minute) or lb/hr (pounds per hour). Choose injectors that are appropriately sized for the target horsepower and boost pressure. Injector Dynamics, DeatschWerks, and Bosch are well-regarded injector manufacturers.

Fuel Pump

An upgraded fuel pump is essential to provide adequate fuel pressure and flow to the injectors. Walbro, AEM, and DeatschWerks offer high-performance fuel pumps that can support a wide range of power levels. Consider using an in-tank fuel pump for ease of installation and reduced noise.

Fuel Pressure Regulator

A fuel pressure regulator maintains constant fuel pressure to the injectors, ensuring consistent fuel delivery. Adjustable fuel pressure regulators allow for fine-tuning of fuel pressure, optimizing performance. Aeromotive and Fuelab are popular manufacturers of fuel pressure regulators.

Engine Management System (EMS)

An engine management system (EMS) controls various engine parameters, such as fuel injection, ignition timing, and boost pressure. An aftermarket EMS allows for precise tuning and optimization of engine performance.

Standalone EMS

Standalone EMS systems offer complete control over engine parameters. Popular options for the 240SX include Haltech, AEM, and Link ECU. These systems require custom tuning to optimize performance for a specific engine setup. A professional tuner is recommended for configuring and tuning a standalone EMS.

Piggyback EMS

Piggyback EMS systems work in conjunction with the OEM ECU, modifying its signals to achieve desired performance. These systems are typically easier to install and tune than standalone EMS systems, but offer less control over engine parameters. APEXi and GReddy offer piggyback EMS systems for the 240SX.

Choosing the right engine components for your Nissan 240SX depends on your budget, power goals, and intended use of the vehicle. Careful planning and research are essential to ensure a successful and reliable build. Consult with experienced tuners and mechanics to determine the best components for your specific needs.