Specifications

For model years 1989 and 1990 the Nissan 240SX used a KA24E.

The KA24E is a 2.4 liter single overhead cam (SOHC) 12-valve engine .It uses SEFI fuel injection, and contrary to popular rumor among KA24 owners, they do not feature forged steel connecting rods, but an internally half-counterweight one-piece cast crankshaft, and a cast aluminum intake manifold.

Bore × Stroke: 89.0 × 96.0 mm
Max power: 140 hp (105 kW) @ 5600 rpm
Max torque: 152 ft·lbf (206 Nm) @ 4400 rpm
Valve Configuration: SOHC, 12 valves
Compression ratio: 8.6:1 (9.1:1 for early 1989 24oSX )

The KA24DE is the stock engine for 1991 to 1998 S13 and S14 240SX vehicles. It is a 2.4 Liter DOHC Engine.

Bore × Stroke: 89.0 × 96.0 mm
Max power: 155 hp (115 kW) @ 5600 rpm
Max torque: 160 ft·lbf (217 Nm) @ 4400 rpm
Valve Configuration: DOHC, 16 valves
Compression ratio: 9.5:1 (S14/95-98) 9.0:1 (S13/91-94)

NA Modifications

Basic N/A tuning can net you average increases out of your KA24DE / KA24E engine. The KA24 is a larger displacement four-cylinder motor. It was mainly built with low-end torque in mind. It also uses a long piston stroke to achieve its torque. This prevents it from having the high rev limit that is seen with other Nissan four-cylinder motors. With the basic bolt-ons, you can expect to see an additional 30 whp depending on the condition of your engine. Don't expect any huge horsepower gains from inexpensive NA modifications. While it's possible to reach 200+ horsepower, it will take superior tuning skills, along with pretty deep pockets. Most of this power is had through ECU tuning and custom parts, including cams, ITB's, larger valves, port and polish, and upgraded valvetrain. A complete engine overhaul is also recommended if any modifications are to be planned. These bolt-on parts are usually installed for KA24 NA buildups:

Header

Aftermarket Engine management

CAI(cold air intake)

Exhaust

ITB's(individual throttle bodies)

Forced Induction

Turbocharging

Supercharging