O.S. Engine OSMG2040 21XZ-R High Response On-Road Engine  [OSMG2040]

O.S. Engine 21XZ-R On-Road ABC w/21M
Price:
AUD$506.30
Brand:
O.S. Engine
Model:
OSMG2040
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Racing Summary for the O.S. Engine 21XZ-R

The O.S. Engine 21XZ-R On-Road ABC w/21M is engineered for competitive 1/8 on-road use where throttle control and repeatable performance are essential. The tungsten-weighted crank provides better rotational balance so the engine maintains usable torque at varying speeds.

Internal Design and Flow Characteristics

The cylinder liner's seven scavenger ports and three exhaust ports are configured to enhance scavenging and combustion. The redesigned crankcase and the 21M carburetor combine to smooth the fuel and air flow, while the lightweight piston and hard-wearing con rod are selected for reliable service in race conditions.

Output, Range and Mass

At 0.284 cu in (4.65 cc) displacement the 21XZ-R delivers 3.31 hp at 32,000 rpm with a usable range of 4,000 to 38,000 rpm. Weighing 13.1 oz (375 g), it is compact enough to help fine-tune chassis balance without sacrificing power.

Specifications

  • Displacement: 0.284 cu in (4.65 cc)
  • Bore: 0.728 in (18.5 mm)
  • Stroke: 0.681 in (17.3 mm)
  • Practical RPM: 4,000-38,000
  • Power Output: 3.31 hp @ 32,000 rpm
  • Weight: 13.1 oz (375 g)

The O.S. Engine 21XZ-R is a practical choice for competitive hobbyists seeking a tunable, durable engine that supports consistent lap times in 1/8 on-road racing.

What electronic setup complements the 21XZ-R?

Pair the engine with a reliable ignition system and high-output servos to handle throttle precision. Choose an exhaust and header that suit your chassis layout to maximise flow.

How does altitude affect tuning?

Higher altitude reduces oxygen density so you may need a richer main needle or higher nitro to maintain power. Check temps and plug condition after adjustments to ensure safe tuning.

Are spare parts easy to source?

Wear items such as pistons, con rods and bearings are standard service parts and can be sourced from specialist suppliers. Keeping spare consumables on hand reduces downtime at race meetings.

What clutch adjustments improve starts?

Tuning shoe pressure and spring tension alters engagement RPM. For quicker launches, increase engagement aggressiveness; for smoother rollouts, soften the setup and test on-track.

How should I monitor engine health after a race?

Inspect the glow plug, check for scoring on the piston, and verify crankcase seals. Regular compression checks and listening for unusual noise are simple ways to spot issues early.

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