2004 S2000 Engine Design - Keys to Note:
- The engine code designation is F22C1 to denote the 2.2 liter size.
- Cylinder bore is 87.0 mm and stroke is 90.7 mm to have a 1:1.04 bore-stroke ratio. The slightly undersquare design provides better torque at lower rpm.
- For comparison, the 2000-2003 model's cylinder bore is 87.0 mm and stroke is 84.0 mm for a 1:0.96 bore-stroke ratio.
- Continues to use traditional VTEC instead of i-VTEC as on the K-series motors.
- Where F20C was known to offer significant power from 6000 rpms onward, the F22C supposedly comes on very strong at only 3000 rpms.
- Honda asserts that the '04 S2000 offers measurably stronger acceleration in each gear
Though they are carry over items, the following items bear mentioning. They are best explained in Honda's words:
Compact High-Output Engine Block
The S2000 engine block is a one-piece, open-deck aluminum-alloy die casting. Of special note are the block's FRM (Fiber-Reinforced Metal) cylinder liners cast integral with the block. FRM is a composite material consisting of carbon fibers embedded in an aluminum oxide matrix (aluminum oxide is a ceramic material used for spark-plug insulators). As a cylinder lining, FRM offers several advantages over conventional ferrous-metal liners, including lower weight, faster heat transfer and a greater resistance to wear. Additionally, "dummy head honing," a process where the engine block cylinders are honed with a "dummy" cylinder head tightened to the block, improves machining accuracy for stability of piston movement.
Externally Mounted Oil Pump
To help minimize engine length, Honda engineers placed the oil pump at the bottom of the engine block instead of its usual location at the front of the crankshaft. This placement provides engine compactness, and the pump scavenges oil more efficiently. Additionally, the oil pump's low placement helps pressurize the lubrication system more quickly during engine startup.
The oil pump itself also is a compact design that uses a smaller, high-speed rotor and suction-pickup ports on both sides of the pump body. The new design supplies a greater volume of oil to the engine at all engine speeds. The oil pump is driven via a silent chain connected to the crankshaft.
Compact Engine Ancillary Drive
The system for the engine ancillaries, such as the alternator, air-conditioning compressor and water pump, can take up considerable space at the front of the engine. So Honda engineers locate them at the side of the engine block (a practice commonly used on racing engines) and designed a compact drive system that uses both sides of a serpentine belt. An automatic tensioner is built into the drive system.
- Reduced shift effort and direct feel from carbon synchronizers on gears one through six
- Compact pull-type clutch mechanism and reinforced friction materials in the high-performance clutch better suited to high-RPM operation
Transmission Gear Ratios
*Net gear ratio change occurs through modification of the
secondary gear reduction ratio inside the transmission.
Source: Honda PR
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