| Manufacturer | Mitsubishi Motors |
|---|---|
| Also called | Cyclone V6 |
| Cylinder block alloy | Cast iron |
The Mitsubishi 6G7 or Cyclone V6 engine is a series of V6 piston engines from Mitsubishi Motors. Five displacement variants have been produced with both single- and double- overhead camshaft layouts. MIVEC variable valve timing has also been implemented in some versions, and the 2.5 and 3.0 L versions were also available with gasoline direct injection. Modern versions feature a one-piece cast crankshaft and cast aluminum intake manifold.
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The 6G71 is a 1,998 cc version with a bore and stroke of 74.7 × 76 mm (2.94 × 2.99 in). It produces 88 kW (120 PS; 118 hp) at 5,500 rpm and 172 N·m (127 ft·lbf) at 4,500 rpm.
The 6G72 is a 2972 cc engine. Bore is 91.1 mm (3.59 in) and stroke is 76 mm (3.0 in). SOHC 12-valve, SOHC 24-valve, and DOHC 24-valve versions have been produced.
The latest version was used in the Mitsubishi Eclipse GT and Galant. Output in 2004 was 210 hp (157 kW; 213 PS) at 5500 rpm with 278 N·m (205 ft·lbf) of torque at 4000 rpm. It has a cast iron engine block and aluminum SOHC cylinder heads. It uses MPFI fuel injection, has four valves per cylinder with roller followers and features fracture-split forged steel connecting rods. In the older version, used in many Chrysler models since 1987 this V6 was a SOHC 12-valve developing 141 hp (105 kW) at 5000 rpm and 172 lb·ft (233 N·m) of torque at 3600 rpm. The Mitsubishi models were with a 3.0 Litre 6G72 engine SOHC 24-valve developing 195 hp (145 kW) at 5000 rpm and 205 lb·ft (278 N·m) of torque at 4000 rpm
The DOHC 24-Valve was used in the Mitsubishi 3000GT and Dodge Stealth producing 222 horsepower (166 kW) and 205 pound-feet (278 N·m) of torque in naturally aspirated form, and as much as 320 horsepower (240 kW) and 315 pound-feet (427 N·m) of torque in turbocharged form.[1] Each bank of the V6 had its own independent turbocharger and intercooler. Turbo chargers were built by Mitsubishi. They were water cooled to ensure longer service life. [2]
The 6G73 displaced 2497 cc. It was a 24-valve SOHC design with 2 valves running off one cam lobe, with a smaller bore than the 3.0 liter version of the same block. Bore and stroke were 83.5 × 76 mm (3.29 × 2.99 in); it was a 60-degree V6 and weighed around 155 kg (340 lb). The engine had low-profile cast aluminum heads which helped it to fit into small engine bays, while pent-roof combustion chambers increased efficiency and made room for four valves per cylinder, arranged in a cross-flow pattern with a "tumble" intake port for both strong breathing and low emissions. Spark plugs were centered in the combustion chambers. The intake valves were 33 mm (1.30 in) in diameter while exhaust valves were 29 mm (1.14 in). A toothed timing belt was used. The output of 6G73 was 161 hp (122 kW; 163 PS) at 5900 rpm with 221 Nm (163 lb-ft) of torque at 4350 rpm.[3]
The 6G74 is a 3497 cc 24-valve unit available with either SOHC, DOHC, or MIVEC DOHC. Bore is 93 mm and stroke is 85.8 mm. Output for the SOHC version varies from 139 kW (189 PS; 186 hp) at 4750 rpm with 306 N·m (226 ft·lbf) of torque at 3750 rpm in the Pajero to 153 kW (208 PS; 205 hp) at 5000 rpm with 313 N·m (231 ft·lbf) of torque at 4000 rpm for other applications. For the MIVEC the output is 194 kW (264 PS; 260 hp) at 6000 and 324 N·m (239 ft·lbf) at 4500. The most common 6G74 has a cast iron engine block and an aluminum cylinder head. It uses MFI fuel injection and uses forged steel connecting rods. The MIVEC version of this engine was only available in the Mitsubishi Pajero Evolution.
The gasoline direct injection version of the 6G74 was launched in April 1997 as the first GDI V6 engine ever produced. It differed from the basic 6G74 in many ways apart from its unique fuel injection system — it had a crown-curved rather than flat combustion chamber, upright intake ports rather than angled, and a 10.4:1 rather than 10.0:1 compression ratio. Mitsubishi claimed 30 percent better fuel economy, a 30 percent reduction in emissions, and higher power outputs than diesels.[4]
The 6G75 is a 3828 cc version with 95 mm (3.74 in) bore and 90 mm (3.54 in) stroke. Output varies from 172 kW (234 PS; 231 hp) and 339 N·m (250 ft·lbf) to 197 kW (268 PS; 264 hp) and 353 N·m (260 ft·lbf) depending on application. It has forged steel connecting rods.
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