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Nissan 240SX - Performance

Aftermarket Parts

Drivetrain

The drivetrain (flywheel, clutch, transmission, driveshaft, and differential) is where much of a carís horsepower is lost. It is important to upgrade the drivetrain if you increase engine power or drive aggressively.


Driveshaft

The first drivetrain upgrade I would make is replacing the 2-piece stock driveshaft with a single-piece part. An aluminum or carbon fiber driveshaft will be lighter and more durable than the stock piece. Aluminum is less expensive, but carbon fiber is lighter and will shatter if it comes loose or begins to break. An aluminum driveshaft is more likely to destroy the underside of your car if it comes loose since it will not disintegrate like the carbon fiber shaft. Drive Shaft Shopís 240SX/Silvia Aluminum Drive Shaft is a good choice for the 1989-94 240SX. It is 40% lighter than the stock piece and rated at 800 hp. The price is $450.


Clutch

The next drivetrain part that should be changed is the clutch. Choosing a clutch is important because it will strongly affect your carís performance and how it behaves on the street. An aggressive clutch is necessary if you are adding significant power, but it will make pressing the clutch more difficult. Also, more aggressive clutches tend to have an on/off button feel instead of a smooth feel, which makes normal driving annoying.

Products - Clutch:
Product Vehicle Notes Price
Clutch Masters FX400 Steel Back Heavy Duty Street Clutch All 240SX models Good clutch for high power turbo 240SX; try FX200 or FX300 for naturally aspirated 240SX $700
Exedy Stage 2 Single Plate Cera-metallic Clutch Kit 240SX with SR20DET Reduced rotational inertia due to thinner layer of friction material $600
ACT Performance Organic Street Disc and Heavy Duty Pressure Plate Clutch All 240SX models Near-stock feel; users have reported friction material shearing off with aggressive driving $350
Clutch Masters FX400 Steel Back Heavy Duty Street Clutch Exedy Stage 2 Single Plate Cera-metallic Clutch Kit ACT Performance Organic Street Disc and Heavy Duty Pressure Plate Clutch
Clutch Masters FX400 Steel Back Heavy Duty Street Clutch
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Exedy Stage 2 Single Plate Cera-metallic Clutch Kit
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ACT Performance Organic Street Disc and Heavy Duty Pressure Plate Clutch
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Flywheel

The engine output is connected to the flywheel. A lighter flywheel will allow the engine to rev up faster and waste less power on spinning the heavy stock flywheel.

Products - Flywheel
Product Vehicle Notes Price
Unorthodox Racing Lightened Aluminum Flywheel All 240SX models High quality flywheel; claims to free up 10-30 hp at the wheels $800
Exedy Flywheel 240SX with SR20DET One-piece design; rated to 15,000 RPM $620
Cusco Chromoly Flywheel All 240SX models Claims to eliminate the erratic idle common with other lightweight flywheels $550
Unorthodox Racing Lightened Aluminum Flywheel Exedy Flywheel Cusco Chromoly Flywheel
Unorthodox Racing Lightened Aluminum Flywheel
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Exedy Flywheel
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Cusco Chromoly Flywheel
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Differential

A differential allows the rear wheels to spin at different speeds in a corner while power is being applied to them. The outside wheel must spin faster since it travels a longer distance than the inside wheel. A Limited Slip Differential (LSD) performs the function of a regular differential but also locks the rear wheels together when one of the wheels begins to slip. Without an LSD, when a wheel slips, the majority of the power goes to that wheel. The power is wasted, and the car does not move forward. To see why this happens, read How Differentials Work from howstuffworks.com.

Cornering ability is improved when an LSD is installed. The two main types of LSDs are viscous LSDs and clutch-type LSDs. A viscous LSD works by using a friction-sensitive fluid positioned between plates connecting the left and right axles. If the axles spin at different speeds, they heat up the fluid. The fluid expands, which locks the two axles together.

The clutch-type LSD works by locking the rear wheels together by using a set of clutches and springs. In order for one of the wheels to spin faster than the other, that wheel must overpower the clutch. This is easy when both wheels are gripping in a corner. However, when one wheel starts to slip, it does not have enough torque on it to overpower the clutch. Therefore, the two wheels are locked together. The stiffness of the springs in the LSD can be used to adjust when the LSD begins to work. Generally, clutch-type LSDs are more durable, responsive, and adjustable. Therefore, most aftermarket LSDs are clutch-type. However, these LSDs require regular maintenance unlike the viscous LSD. Certain models of the 240SX came with a viscous LSD (see Optional Performance Equipment).

The S15 came with a helical (AKA Torsen) LSD, a third type of LSD. However, even if your car came with a viscous or helical LSD, it is wise to upgrade to an aftermarket clutch-type unit. It will be better suited for high horsepower engines and aggressive driving.

When researching various LSDs to purchase, you will see the terms 1-way, 2-way, and 1.5-way differentials. A 1-way differential only locks on acceleration. A 2-way locks on both acceleration and deceleration. A 1.5-way LSD is the same as a 2-way except that the lock-up rates are different for acceleration and deceleration. The 1.5-way LSD makes the car easier to turn on corner-entry as compared to using the 2-way.

As a rule of thumb, research the manufacturers that supply parts to racing teams if you are unsure of which company to go with. For example, many racing teams use Kaaz and Cusco LSDs.

Products - Differential
Product Vehicle Notes Price
Kaaz 2-way LSD 240SX models sold without the Viscous LSD Durable, high-quality LSD $1,000
Cusco 2-way LSD Type MZ2 All 240SX models Mild streetable LSD; Cusco's type RS is more of a racing LSD $1,000
NISMO 2-way LSD All 240SX models 4-pinion, 70 lb. ft. breakaway torque $900
Kaaz 2-way LSD Cusco 2-way LSD Type MZ2 NISMO 2-way LSD
Kaaz 2-way LSD
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Cusco 2-way LSD Type MZ2
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NISMO 2-way LSD
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