Mitsubishi 4A3 engine


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 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.
A long-stroke, version was made available in 1997 for larger-engined kei derivatives, and was subsequently fitted to the Mitsubishi Pistachio, a limited production car based on the kei class Minica equipped with the company's Automatic Stop-Go system for cutting the engine when idling. So equipped, the Pistachio was able to record fuel economy figures of.

4A30

Displacement —
Bore x Stroke —
Fuel type — Unleaded regular gasoline.
A lean-burn variant, using Mitsubishi's "Vertical Vortex" system, appeared on the new, second-generation Pajero Mini in October 1998. The new engine cut emissions and fuel consumption by about ten percent, in spite of the new model being marginally larger and heavier.

659 cc Electronic carburettor (1993)

  • Engine type — Inline 4-cylinder SOHC 16v
  • Fuel system — Electronic carburettor
  • Compression ratio — 10.0:1
  • Power — at 7500 rpm
  • Torque — at 5500 rpm

659 cc SOHC (1993)

  • Engine type — Inline 4-cylinder SOHC 16v
  • Fuel system — Multipoint ECI
  • Compression ratio — 10.0:1
  • Power — at 7000 rpm
  • Torque — at 5000 rpm

659 cc MVV (1998)

  • Engine type — Inline 4-cylinder SOHC 16v
  • Fuel system — Multipoint ECI, lean burn (MVV)
  • Compression ratio — 10.0:1
  • Power — at 6500 rpm
  • Torque — at 4500 rpm
  • Production – 1998–2002

659 cc DOHC 20v turbo (1993)

  • Engine type — Inline 4-cylinder DOHC 20v
  • Fuel system — ECI multiple
  • Compression ratio — 8.5:1
  • Power — at 7500 rpm
  • Torque — at 3500 rpm

4A31

Displacement —
Bore x Stroke —
Fuel type — Unleaded regular gasoline
The regular 4A31 engine met Euro 2 or 3 emissions standards, depending on model and year, while the GDI version was capable of Euro 4.

1094 cc SOHC (1997)

;Engine type: Inline 4-cylinder SOHC 16v
;Fuel system: ECI multiple
;Compression ratio: 9.5:1
;Power: Pajero Junior: at 6000 rpm
;Torque: Pajero Junior: at 4000 rpm

1094 cc GDI (1999)

;Engine type: Inline 4-cylinder DOHC 16v
;Fuel system: GDI Direct Injection
;Compression ratio: 11.0:1
;Power: at 6000 rpm
;Torque: at 4000 rpm