The 6G7 series or Cyclone V6 engine is a series of V6piston engines from Mitsubishi Motors. Five displacement variants have been produced from 1986 to present day, with both SOHC and DOHC, naturally aspirated and turbo charged layouts. While MIVECvariable valve timing has also been implemented in some versions the 2.5, 3.0 and 3.5 L versions were also available with gasoline direct injection. This engine has been the flagship powerplant of the company except when they briefly built a V8 in 1999–2001. The staple of their high-end sedans, it was given twin-turbos for the Mitsubishi GTO, and became the most powerful car ever built by the company at the time.
Bore and Stroke
6G71
The 6G71 model featured SOHC and produced at 5,500 rpm and at 4,500 rpm. It was installed with two valves per cylinder, and used Mitsubishi's ECI-Multi multiple port fuel injection fuel delivery system. The compression ratio was 8.9:1. An earlier version, with single-point fuel injection, only had at 5,000 rpm and at 4,000 rpm. A supercharger was installed and exclusive to the Debonair. It produces at 5,000 rpm and at 3,000 rpm. The compression ratio for the supercharged model is 8.0:1. The 6G71 engine was also converted to run onLPG, a version which was only available to the Debonair and mainly intended for commercial use.
The 6G72 was manufactured in three different models which featured SOHC with 12-valves, SOHC with 24-valve, and DOHC with 24-valves. The latest version was used in the Mitsubishi Eclipse GT and Galant. Output in 2004 was at 5500 rpm with of torque at 4000 rpm. In the older version, used in many Chrysler models since 1987 this V6 was a SOHC 12-valve developing at 5000 rpm and of torque at 3600 rpm. The Mitsubishi models were with a 3.0 Litre 6G72 engine SOHC 24-valve developing at 5000 rpm and of torque at 4000 rpm. For the MIVEC engine output is at 6000 rpm and at 4500 rpm. The SOHC 12-valve for the second generation of Pajero can provide and, the SOHC 24-valve can provide and. The DOHC 24-Valve was used in the Mitsubishi Debonair, 3000GT and Dodge Stealth producing and of torque in naturally aspirated form, and as much as and of torque in turbocharged form. Each bank of the V6 had its own independent turbocharger and intercooler. Turbo chargers were built by Mitsubishi.
The 6G73 is a 24-valve SOHC design with two valves running off a single cam lobe on the exhaust valves using a forked rocker arm and each intake valve actuated with two cam lobes, with a smaller bore than the 3.0 liter version of the same block. Bore and stroke are ; it is a 60-degree V6 and weighs around. The engine has low-profile cast aluminum heads which help it to fit into compact engine bays, while pent-roof combustion chambers increase efficiency and make 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 are centered in the combustion chambers. The intake valves are in diameter while exhaust valves are. The SOHC 24 valve version of the 6G72 uses these same cylinder heads. A toothed timing belt is used. The output of 6G73 is at 5,900 rpm with of torque at 4,350 rpm.
The 6G74 is a 24-valve unit available with either SOHC, DOHC, or MIVEC DOHC. Output for the SOHC version varies from at 4,750 rpm with of torque at 3,750 rpm in the Pajero to the highest output of at 5,250 rpm with of torque at 4,500 rpm in the Australian-made Magna Sports, VR-X and Verada GTV/GTVi and at 5,500 rpm with of torque at 4,000 rpm in the Magna Ralliart. For the MIVEC, only available in the Mitsubishi Pajero Evolution, the output is at 6,000 and at 4,500 rpm. It uses Multi-port fuel injection and uses forged steel connecting rods. 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 piston head, 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.
The 6G75's Output varies from and to and depending on application. In the interest of durability, the pistons are high-pressure castings attached to forged steel connecting rods that swing from a heat-treated forged steel crankshaft.
