3A9x family
| 3A9x | |
|---|---|
 | |
| Overview | |
| Manufacturer | MDC Power Mitsubishi |
| Layout | |
| Configuration | Inline 3 |
| Cylinder block alloy | Aluminum die-cast |
| Cylinder head alloy | Aluminum die-cast |
| Valvetrain | Direct acting DOHC, 12 valves, continuously variable MIVEC intake valve timing |
The 3A9x family is a series of compact three-cylinder engines developed alongside the four-cylinder 4A9x family. These engines feature an all-aluminum construction, chain-driven double overhead camshafts (DOHC), and four valves per cylinder (12 total).
Key Features
- MIVEC (Mitsubishi Innovative Valve timing Electronic Control): Continuously variable valve timing is used on the intake camshaft (with the exception of the 1.1L 3A91).
- Efficiency: Under light loads, the MIVEC system closes the inlet valves late to reduce pumping losses and improve fuel economy.
- Shared Architecture: To streamline manufacturing, each 3A9x model shares the same bore and stroke measurements as its corresponding 4A9x sibling.
Characteristics
The 3A9x family has earned a reputation for being simple and reliable. It is not uncommon for these engines to reach over 300,000 kilometres without failure.
Like most three-cylinder engines, they are unbalanced and produce a unique, growly exhaust note and minor vibration at idle.
Instead of using turbochargers, the 3A9x family stays naturally aspirated keeping fuel economy remarkably consistent.
The 3A9x family has a remarkably flat torque curve, helping them to feel capable in city traffic. Peak torque arrives relatively late (between 3,500 and 5,000 rpm), but because of the MIVEC system, about 90% of that torque is available from as low as 2,000 rpm.
Production
- 2003–2011: Manufactured at the MDC Power facility in Germany (a joint venture between Mitsubishi and Daimler-Chrysler).
- 2012–Present: Production relocated to Mitsubishi’s Kyoto facility in Japan.
3A90
Specifications
| Displacement | 999cc (1.0 litre) |
| Bore | 75.0mm |
| Stroke | 75.4mm |
| Compression Ratio | 10.5:1 |
| Output | 52 kW @ 6000 rpm, 88 Nm @ 5000 rpm |
Used in
- Sixth Generation Mirage (non Australian market)
3A91
Specifications
| Displacement | 1124cc (1.1 litres) |
| Bore | 75.0mm |
| Stroke | 84.8mm |
| Compression Ratio | 10.0:1 |
| Output | 55 kW @ 6000 rpm, 100 Nm @ 3000 rpm |
When used in the Smart, Mercedes refer to the engine as the M134.
Used in
- Colt Z30 (European market)
- Smart ForFour (not in Australia)
3A92
Specifications
| Displacement | 1193cc (1.2 litres) |
| Bore | 75.0mm |
| Stroke | 90.0mm |
| Compression Ratio | 10.5:1 |
| Output | 57 kW @ 6000 rpm, 100 Nm @ 4000 rpm |
Used in
| MITSUBISHI PETROL ENGINES | |
| 3 cylinder | |
| 3A9x | 3A90 3A91 3A92 |
| 4 cylinder | |
| Neptune | 4G41 4G42 |
| Orion | 4G11 4G12 4G13 4G15 4G17 4G18 4G19 G4ED |
| Sirius | 4G61 4G62 4G63 4G64 4G67 4G69 |
| Astron | 4G51 4G52 4G53 4G54 |
| Astron II | Original Revised |
| Saturn | 4G30 4G31 4G32 4G33 4G37 |
| 4G9x | 4G91 4G92 4G93 4G94 |
| 4A9x | 4A90 4A91 4A92 |
| 4B1x | 4B10 4B11 4B11T 4B12 |
| Inline 6 | |
| Saturn 6 | 6G34 |
| V6 | |
| 6G7x | 6G71 6G72 SOHC 12v 6G72 SOHC 24v 6G72 DOHC Early 6G74 Late 6G74 Ralliart 6G74 6G75 |
| 6A1x | 6A10 6A11 6A12 6A13 |
| 6B3x | 6B31 |
| V8 | |
| 8A80 | 8A80 |
