Honda K20A2 Specifications
| Engine Model: Honda K20A2 |
| Engine Type: 4-cycle inline 4-cylinder DOHC 16-valve i-VTEC liquid-cooled gasoline |
| Total Displacement: 121.9 cu.in (1.99 L) |
| Rated Engine Power: 200 Hp (149 kW) at 7400 rpm |
| Fuel System Type: Multi-point programmed fuel injection (PGM-FI) |
____________________________________________________________________________________
The Honda K20A2 is one of the most iconic
naturally aspirated 2.0-liter inline-four engines ever produced by
Honda. Introduced in the early 2000s for the Acura RSX Type-S (and
related global performance variants), the K20A2 quickly earned a
reputation for exceptional high-rpm performance, precise engineering,
and remarkable durability.
It belongs to the first generation of Honda’s K-series - the successor
to the B-series engines - and represents a major leap forward in terms
of airflow efficiency, structural stiffness, friction reduction, and
electronic engine management.
Unlike the economy-oriented K20A3, the K20A2 is a full performance
engine equipped with Honda’s advanced i-VTEC system operating on both
intake and exhaust camshafts. The ECU controls phasing, lift, and
duration to optimize torque at low rpm and maximize airflow at high rpm.
The result is an engine capable of revving to over 8,000 rpm with
linear, explosive top-end power while maintaining excellent drivability
and reliability.
The K20A2 is a four-stroke, liquid-cooled inline-four gasoline engine
with a displacement of 1,998 cc (121.9 cubic inches). Bore and stroke
both measure 86.0 mm (3.39 inches), giving the engine a square layout
that promotes balanced torque and high-rev breathing. The compression
ratio is 11.0:1 in most factory calibrations.
Factory output:
- Power: 200 hp (149 kW) at 7,400 rpm
- Torque: 193 Nm (142 lb-ft) at 6,000 rpm
- Rev limiter: approx. 8,200 rpm
- Idle speed: approx. 750 rpm
Firing order is 1-3-4-2, using coil-on-plug ignition controlled by the
ECU. The rotating assembly includes a forged steel crankshaft supported
by five main bearings, forged connecting rods, and aluminum pistons with
friction-reducing skirt coatings. The lightweight internal architecture
supports high-rpm operation without excessive stress.
The cylinder block is aluminum with cast-iron cylinder liners to provide
a combination of light weight and durable cylinder walls. It employs an
open-deck structure with strategically strengthened support ribs to
maintain rigidity under high-rpm load. The block is deep-skirted,
reducing flex and enhancing NVH performance.
A cast aluminum main bearing girdle ties all five main caps together,
significantly increasing block stiffness and keeping the crankshaft
stable during high-rpm operation. Oil passage routing is optimized for
reliable lubrication at high g-forces, and piston cooling jets under
each cylinder reduce crown temperature during extended high-load use.
The aluminum DOHC cylinder head is one of the K20A2’s greatest
engineering achievements. It includes four valves per cylinder, operated
through low-friction roller rocker arms. Honda’s performance i-VTEC
system integrates variable cam lift with continuously variable intake
cam phasing, allowing the ECU to precisely control cylinder filling and
scavenging across the entire RPM range.
Valve sizes:
- Intake valves: 35 mm (1.38 in)
- Exhaust valves: 30 mm (1.18 in)
The high-flow port design provides excellent volumetric efficiency,
while the pent-roof combustion chamber shape promotes rapid flame
propagation and stable ignition. Camshafts are driven by a silent-type
chain with hydraulic tensioning.
Fuel delivery uses Honda’s PGM-FI sequential multi-point electronic
injection system. Fuel pressure is maintained at approximately 350-380
kPa (51-55 psi) using a returnless rail.
Sensors include:
- MAP / MAF (market dependent)
- IAT (intake air temperature)
- ECT (engine coolant temperature)
- TPS (throttle position)
- Primary wideband O2 sensor
- Secondary O2 sensor
- Knock sensor
- Crankshaft position (CKP)
- Camshaft position (CMP)
Injectors are multi-hole high-flow units designed to meet the airflow
demands of high-rpm operation. Recommended fuel is premium unleaded
gasoline (minimum 95 RON / 91 AKI).
The lubrication system uses a full-pressure wet-sump layout with a
crank-driven trochoid oil pump.
Specifications:
- Oil capacity with filter: 4.4 liters (4.6 qt)
- Oil pressure at 3,000 rpm: 350-500 kPa (51-72 psi)
- Idle pressure: 80-120 kPa (12-17 psi)
Piston cooling jets help maintain piston temperatures under sustained
high-rpm load. Recommended viscosity is 5W-30 or 5W-20 depending on
climate. Oil should be replaced every 8,000-10,000 km (5,000-6,000
miles).
Cooling is handled by a liquid-cooling forced-circulation system using a
belt-driven water pump.
Specifications:
- Coolant capacity: 6.5 liters (6.9 qt)
- Thermostat opening: 78-82°C (172-180°F)
- Fully open: approx. 95°C (203°F)
The aluminum radiator and dual electric fans maintain temperature
control even under high-rpm operation. Coolant should be replaced every
40,000 km (25,000 miles) or 2 years.
| Intake and Exhaust Systems |
The K20A2 uses an efficient cast aluminum intake manifold, high-flow
airbox, and 62-mm throttle body. The geometry of the intake runners
enhances mid-range torque without sacrificing top-end power.
Exhaust components:
- Performance-tuned 4-2-1 stainless manifold
- High-flow catalytic converter
- Stainless mid-pipe and muffler (vehicle dependent)
The tuned exhaust system complements the head’s flow characteristics to
produce excellent high-rpm power.
| Ignition and Electrical System |
Ignition uses coil-on-plug modules controlled by the ECU. Iridium spark
plugs ensure consistent spark at high rpm.
Electrical specs:
- Alternator Output: approx. 100-120 A
- Starter Motor: approx. 1.2-1.4 kW
- Electrical System: 12 V
ECU controls include ignition timing, VTEC activation, cam phasing,
OBD-II diagnostics, idle speed control, knock protection, and fuel
mapping.
- Length: 650 mm (25.6 in)
- Width: 610 mm (24.0 in)
- Height: 690 mm (27.2 in)
Dry weight: approx. 145-150 kg (320-331 lb).
- Oil and filter: 8,000-10,000 km
- Air filter: 20,000-30,000 km
- Spark plugs: 100,000 km
- Coolant: 40,000 km or 2 years
- Valve clearance: inspect every 120,000 km
- Drive belt: inspect every 30,000 km
- Compression test: 190-220 psi (1,310-1,515 kPa)
- Cylinder head bolts: 30 Nm + 90° + 90°
- Main bearing caps: 60 Nm
- Connecting rod bolts: 40 Nm + 90°
- Flywheel bolts: 88 Nm
- Crank pulley bolt: 180 Nm
- Intake manifold bolts: 22 Nm
- Exhaust manifold nuts: 30 Nm
- Spark plugs: 18 Nm
- Oil drain plug: 40 Nm
- Acura RSX Type-S (2002-2004)
- Honda Integra Type-R (regional variants)
- Honda Civic / Accord engine swaps (performance builds)
____________________________________________________________________________________
| Car Engines Technical Specifications |
| Small Engines Technical Specifications |
| Industrial Engines Technical Specifications |
| Outboard Engines Technical Specifications |
