U.S. Spec
Year: 1989-1990
Vehicle: Nissan 240sx
Engine: KA24E
Year: 1991-1994
Vehicle: Nissan 240sx
Engine: KA24DE
Year: 1995-1998
Vehicle: Nissan 240sx
Engine: KA24DE
KA Engine Outputs (information compiled by BigVinnie @ s-chassis.com)
Redline: 6500RPM
1989 KA24E
9.1:1 Compression Ratio
144 HP 5600RPM 155LB/FT torque @4400
1990 KA24E
8.6:1 Compression Ratio
140 HP@ 5600RPM, 155LB/FT torque @4400
1991-1994 KA24DE
9.2:1 Compression Ratio
155 HP @ 5600RPM, 156 LB/FT torque 4400
1995-1998 KA24DE
9.5:1 Compression Ratio
156HP @ 5600RPM, 160 LB/FT torque 4400 RPM
*Engine Output is rated from factory (most likely from the clutch). There have been dynos done on completely stock SOHC and DOHC KA engines that show engine output anywhere from 100whp-120whp (measured at the wheels). The Power Output drops when you measure from the wheels because of parasitic HP loss through the vehicle's drivetrain.
**S13 KA24DE used 240/248 Cams while the S14 KA24DE used 232/232 Cams. Why such similar power outputs? The S13 ECUs and S14 ECUs use different fuel maps.
Features of the KA Engine (information attributed by Motorworx @ zeroyon.com)
- Cast Pistons (Not Strong)
- Forged Steel Connecting Rods (Strong) [note: KA rods are said to shotpeened vs being forged, once I can take a look at a conrod, i'll let you all know]
- Forged Steel Crankshaft (Strong)
- 86mm Bore
- 96mm Stroke (Long Stroke = Not Designed for High Revs)
- Iron Block (Strong but Heavy)
- Aluminum Cylinder Head (Light)
- Broad Powerband due to the long stroke
- Larger Ports vs SR Engine
- Larger Valves vs SR Engine
- Larger Pistons vs SR Engine
- Cam-On-Lifter Head Design (Reliable and Durable) vs SR Engine Throw-The-Rocker Head (Wandering Rocker Arms @ High RPM)
Although the stock SR20DET (T for Turbo) engine puts out more HP than a KA24DE engine, the KA24DE is designed beefier than the SR20DET. The only real design quirk of the KA is the high stroke which limits the ability of the engine to rev very high. A shorter stroke engine can rev higher because of less rotational inertia. It has less distance to travel for a full rotation. The higher the rpm the more critical it is for bottom end components to be balanced in order to handle the high number of rotations without "wobbling" or causing excess vibration. The longer the rotation (the longer the stroke), the more well balanced the components must be in order to handle the longer distances the rod and piston must travel.
No Revs???
So what to do with a beefy engine that doesn't rev high? You apply forced induction. Forced Induction includes the use of Nitrous Oxide (NOS/Naaaawwwwzzzzz), Superchargers, Turbochargers, or any mix of the three.
Nitrous Oxide is an expendable source of power that comes in the form of High Pressure Tanks. Current technology enables users to employ NOS with the push of a button, at any given RPM, at any given Throttle Position, can be employed in stages of different amounts of boost, etc. I see NOS as an effective source of power for straightaways... and only straightaways. There are D1 drift cars using NOS for a little extra umph, but for the simple fact that it's all gone when the bottle is empty doesn't excite me one bit.
Turbochargers use exhaust gases to spin a turbocharger to produce boost. There are many examples of turbocharged KA engines running serious amounts of boost producing seriously insane numbers on the Dyno. You can fabricate your own turbo kit on the cheap, or shell out buku bucks for pre-made kits.
Superchargers produce boost off engine pulleys. Thomas Knight makes a supercharger kit for the KA24DE but not a lot of information is available from their site... other than it's expensive (cho takai!). There have also been some enthusiasts adapting a Nissan Pathfinder supercharger to work on the KA24DE with custom brackets, pulleys and belts.
There have been KA engines built to make 200whp NA spending upwards of $1,000 on parts, but it is not very cost effective or emissions compliant in California.
All in all, the KA engines are good, reliable, torque-y engines by design. Some may argue that the best way to make power in a 240sx is to swap in an SR20 turbo engine, but if you take the time and realize what you have, you'll know that you have a diamond in the rough.
- Mainichi Tuning
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