Mitsubishi 4A3 engine

Reciprocating internal combustion engine

Mitsubishi 4A3 engine

Overview
Manufacturer	Mitsubishi Motors
Production	1993–present
Layout
Configuration	Inline-four
Displacement	0.7–1.1 L (659–1,094 cc)
Cylinder bore	60 mm (2.36 in) 66 mm (2.6 in)
Piston stroke	58.3 mm (2.30 in) 80 mm (3.15 in)
Cylinder block material	Cast iron
Cylinder head material	Aluminium
Valvetrain	SOHC 4 valves x cyl. DOHC 5 valves x cyl.
Compression ratio	8.5:1-11.0:1
Combustion
Turbocharger	On 1993 0.7 L (659 cc) DOHC only
Fuel system	Electro carburettor Electronic fuel injection Direct Injection
Fuel type	Gasoline
Cooling system	Water-cooled
Output
Power output	50–78 PS (37–57 kW)
Torque output	56–103 N⋅m (41–76 lb⋅ft)

The Mitsubishi 4A3 engine is a range of alloy-headed inline four-cylinder engines from Mitsubishi Motors, introduced in 1993 in the sixth generation of their Mitsubishi Minica kei car. It shares a 72 mm (2.8 in) bore pitch with the 3G8-series three-cylinder engines, but has a considerably shorter stroke so as to stay beneath the 660 cc limit imposed by the Kei class.^[1]

A 1.1 L (1,094 cc) version was made available in 1997 for larger cars, and was subsequently fitted to the Mitsubishi Pistachio, (and Pajero JR), a limited production car based on the kei class Minica equipped with the company's Automatic Stop-Go (ASG) system for cutting the engine when idling. So equipped, the Pistachio was able to record fuel economy figures of 30 km/L (85 mpg_‑imp; 71 mpg_‑US).

4A30

Displacement — 0.7 L (659 cc)
Bore x Stroke — 60 mm × 58.3 mm (2.36 in × 2.30 in)
Fuel type — Unleaded regular gasoline

659 cc Electronic carburettor (1993)

Engine type — Inline 4-cylinder SOHC 16v
Fuel system — Electro carburettor
Compression ratio — 10.0:1
Power — 50 PS (37 kW) at 7500 rpm
Torque — 56 N⋅m (41 lb⋅ft) at 5500 rpm

659 cc SOHC (1993)

Engine type — Inline 4-cylinder SOHC 16v
Fuel system — ECI multiple
Compression ratio — 10.0:1
Power — 55 PS (40 kW) at 7000 rpm
Torque — 60 N⋅m (44 lb⋅ft) at 5000 rpm

659 cc DOHC turbo (1993)

Engine type — Inline 4-cylinder DOHC 20v
Fuel system — ECI multiple
Compression ratio — 8.5:1
Power — 64 PS (47 kW) at 7000 rpm
Torque — 97 N⋅m (72 lb⋅ft) at 3500 rpm

4A31

Displacement — 1.1 L (1,094 cc)
Bore x Stroke — 66 mm × 80 mm (2.60 in × 3.15 in)
Fuel type — Unleaded regular gasoline

1094 cc SOHC (1997)

Engine type: Inline 4-cylinder SOHC 16v
Fuel system: ECI multiple
Compression ratio: 9.5:1
Power: Pajero Junior: 80 PS (59 kW) at 6000 rpm; Toppo BJ Wide: 78 PS (57 kW) at 6000 rpm; Town Box Wide: 75 PS (55 kW) at 6000 rpm
Torque: Pajero Junior: 98 N⋅m (72 lb⋅ft) at 4000 rpm; Toppo BJ Wide: 103 N⋅m (76 lb⋅ft) at 4000 rpm; Town Box Wide: 100 N⋅m (74 lb⋅ft) at 4000 rpm