Mitsubishi 6G7 engine


The 6G7 series or Cyclone V6 engine is a series of V6 piston engines from Mitsubishi Motors. Five displacement variants were produced from 1986 to 2021, with both SOHC and DOHC, naturally aspirated and turbo charged layouts. The 2.5, 3.0, and 3.5 L versions were also available with gasoline direct injection. MIVEC variable valve timing was used in some versions 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.
This engine was also manufactured by Hyundai Motor Company in South Korea as the Hyundai Sigma engine.

6G71

The 2.0-litre 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 on LPG, a version which was only available to the Debonair and mainly intended for commercial use.

Applications

6G72

The 3.0-litre 6G72 was manufactured in three different models which featured SOHC with 12 valves, SOHC with 24 valves, 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 an SOHC 12-valve developing at 5000 rpm and of torque at 3600 rpm. The Mitsubishi models were with a 3.0L 6G72 engine SOHC 24-valve developing at 5000 rpm and of torque at 4000 rpm. For the MIVEC engine, output was at 6000 rpm and at 4500 rpm.
The SOHC 12-valve for the second generation of Pajero could produce up to and, whereas the SOHC 24-valve could produce up to and.
The DOHC 24-valve was used in the Mitsubishi Debonair, 3000GT, and Dodge Stealth producing and of torque with a 10.0:1 compression ratio in naturally aspirated form, and as much as and of torque in turbocharged form. The turbocharged variant had the lowest compression ratio at 8.0:1, with each bank of the V6 having its own independent turbocharger and intercooler. Turbochargers were built by Mitsubishi.

Applications

6G73

The 2.5-litre 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 3.0L 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.

Applications

6G74

The 3.5-litre 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 a 10.0:1 compression ratio. Mitsubishi claimed 30 percent better fuel economy, a 30 percent reduction in emissions, and higher power outputs than diesels.

Applications

6G75

The 3.8-liter 6G75's output varied from and to and depending on application. The block was taller than that of the 3.5-liter 6G74. The pistons were high-pressure castings, joined to forged steel connecting rods and a heat-treated, forged steel crankshaft. Intended to be used with 95 RON fuel, lower octane fuels would be detected by the vehicle's knock sensors, and the engine detuned to compensate.

Specifications

  • Engine type: V type, single overhead camshaft
  • Bore × stroke:
  • Displacement:
  • Combustion chamber: pentroof type
  • Compression ratio: 10.5:1, 10:1
  • Firing order: sequential 1-2-3-4-5-6
  • Lubrication system: Pressure feed, full-flow filtration
  • Lash adjusters on intake and exhaust
  • Fuel delivery system: Electronically controlled MFI
  • Fuel grade: Factory-tuned for 95 RON unleaded petrol
  • Ignition system: Electronically controlled 6-coil
  • Oil pump type: Trochoid type

Applications