The number and lettering system of Mitsubishi engines can be a little confusing, so here is how to decipher them:
Numerical Prefix -
4 = four cylinder
6 = six cylinder
Numerical Suffix -
12 = 2.0 litre
13 = 2.5 litre
36 = 2.0 litre
54 = 2.6 litre
61 = 1.6 litre
62 = 1.85 litre
63 = 2.0 litre
64 = 2.4 litre
72 = 3.0 litre
73 = 2.5 litre
74 = 3.5 litre
91 = 1.5 litre
92 = 1.6 litre
93 = 1.8 litre
The entire range of high performance Mitsubishi sixes is set in a V configuration. Starting off with the most powerful, the 6G72 twin turbo engine is responsible for pushing the heavy 3000GT/GTO to 100 km/h in around five seconds. Its attributes are a displacement of 3.0 litres, 8.0:1 compression, quad cams, 24 valves, twin (simultaneous) turbos, dual air-to-air intercoolers and a sophisticated EFI system - all giving a total output of 209kW at 6000 rpm, with a bag of 427Nm at only 2500 rpm! Now that would make one awesomely flexible road-car engine! In Japan, development of this engine has been quite minor in comparison to the Nissan RB26DETT, but we'd expect that you could attain around 300kW with simple exhaust, intake, intercooler and boost modifications.
A high performance naturally aspirated version of this engine (also called the 6G72), is available minus all the turbo intake trickery, but with a higher static compression ratio of 11.0 to help compensate. It makes 179kW at 5750 and 304Nm at 3500. A lower spec trim again can be found, which is good for 168kW and 275Nm, and yet another (as in the Japanese Diamante/Magna) is capable of 127kW and 248Nm.
About 17% larger at 3.5 litres, the DOHC 6G74 turbo comes suitable for front and all-wheel-drive and produces 194 kW at 6000 rpm.
The Japanese market Diamante is also powered by a 10.0:1 compression ratio atmospherically inducted 6G74 3.5 litre, that produces 194kW at 6000 and 324Nm at 4500 rpm. In between the 3.0 and 2.0 V6s is the 6G73 2.5 litre motor. Available in FWD atmo form only, this DOHC powerplant shares its basic design with the other engines in the 6G range, and is good for 131kW at 6000 revs.
A way - other than by turbocharging - that Mitsubishi has been able to develop big power from their engines has been through the use of the latest MIVEC (Mitsubishi Innovative Valve and Lift Electronic Control System) technology. This system employs a multi-mode variable valve timing mechanism set in three modes - low speed, high speed and MD (modulated displacement). The resulting optimised flow of gas through the heads enables these engines to deliver a substantial increase in torque across the entire rev range - but especially in the higher revs, where conventional engines are usually set with conservative valve lift and duration.
Displacing only 2 litres, the atmo MIVEC version of the 6A12 DOHC V6 with its 10.0:1 compression ratio is listed at an impressive 149kW at 7500 rpm and 200Nm at 6000. This engine is most widely-noted for its fitment to the sexy looking Mitsubishi FTO, which it powers from 0-100 km/h in under 8 seconds. There's also another atmo 6A12 engine (in either FWD or AWD configuration) that is the same as above but minus the MIVEC system and some compression points. It is capable of delivering a total of 127kW at lower revs
A turbo version of the non-MIVEC 6A12 engine was released too, which could pull 149kW - the same peak power as the wonderful atmo inducted MIVEC!
Mitsubishi's selection of four cylinders is where the company has earned the majority of its performance reputation.
One of the old-school engines Mitsubishi produced in the 80s is the SOHC injected G63B turbo. This engine came available in a number of different specs, but the most desirable is the 3 valves per cylinder 2 litre DASH engine which came in either FWD and RWD guise. This non-intercooled engine was able to stomp out a creditable 149kW at 6000 rpm and 280Nm of torque.
However, the more common version of this engine (also called the G63B) is the 2 valves per cylinder SOHC as found in the Starion/Conquest. This is still capable of a reasonable 131kW at 5500 rpm and 216Nm at 3500 rpm.
At about the same time (the early 80s) the Mitsubishi Cordia GSR hit the streets with very similar technology to the G63B - albeit in a smaller overall package, called the G62B. This 1.85 litre SOHC four was also non-intercooled (like most turbos of the time), and in the ultimate versions used a large capacity turbocharger to help it on the way to a maximum of 119kW at 5800 rpm and 216Nm at 3500.
The next generation of Mitsu fours was all based on the same blocks as those mentioned above, but sported DOHC heads to aid breathing. Amongst this late-80s group of engines is the front wheel drive 4G36 that came in some of the mid/compact size vehicles, sweeping a volume of 2.0 litres and producing 104kW at 6000 rpm.
One of the engines most widely used in competition (especially rally) is the DOHC 4G63 turbo engine. Available in a variety of specs, this engine comes in 2.0 litre capacity and is good for up to 209kW at 6500rpm, and 373Nm at 3000 in the Evolution 6.
Released in both FWD and 4WD configurations, the double over head cam 4G93 atmo and turbo moves 1.8 litres, and generates 112kW at 6500 and 145kW at 6000 rpm respectively. One power-pack for the compact Japanese-spec Lancer GSR hatches was the 4G61 engine that pushed around 1.6 litres, used DOHCs and a single intercooled turbo to create a maximum of 108kW at 6000 revolutions. A smaller engine, the 1.5 litre DOHC 4G91, was a front-wheel-drive-only engine that was designed for use in hatchbacks, mustering up 86kW at 6000 revs with a peak of 137Nm of torque.
The latest MIVEC four cylinder is becoming quite popular in Japan (the only country where it is commercially available), and is an optional fitment to the Mirage, FTO and Lancer. The engine we're interested in here is the 1.6 litre 4G92 front wheel drive, that's good for an astounding 131 kW at a substantial 7500 revs per minute, plus 167Nm of torque at a sky-high 7000. This awesome little engine therefore has a specific power output of 81.8kW per litre - enough to rival even some of the best of the current turbo engines!
Mitsubishi performance motors at a glance...
6G74 3.5 DOHC turbo
6G74 3.5 DOHC 194kW
6G72 3.0 DOHC twin turbo 209kW
6G72 3.0 DOHC 179kW/127kW
6G73 2.5 DOHC 131kW
6A12 2.0 DOHC MIVEC 149kW
6A12 2.0 DOHC turbo 149kW
6A12 2.0 DOHC 127kW
4G63 2.0 DOHC turbo 164kW
G63B DASH 2.0 SOHC 12 valve turbo 149kW
G63B 2.0 SOHC turbo 131kW
G62B 1.85 litre SOHC turbo 119kW
4G64 2.4 SOHC 108kW
G54B 2.6 SOHC turbo 131kW
4G91 1.5 DOHC 86kW
4G92 1.6 DOHC MIVEC 131kW
4G93 1.8 DOHC 112kW
4G93 1.8 DOHC turbo 145kW
4G36 2.0 DOHC 104kW
4G61 1.6 DOHC turbo 108kW
4g32 - 1600cc
4g33 - 1800cc
4g34 - 1400cc
Example: 4G61T (1.6L I4 turbo motor in the Colt/Mirage turbo)
4 = 4-cylinder
G = Gasoline, Iron Block. (D = Diesel ie 4D65)
6 = Engine Series
1 = Engine Model (Doesn't equate to capacity, as a higher number can belong to a lesser cc'd engine.)
T = Turbo (This is more of an adopted addition to the engine codes, rather than an official part of it. The official way Mistubishi will list the motor is "4G61 Turbo".)
Example: 6A13TT (2.5L V6 twin-turbo motor in the Galant/Legnum VR-4)
6 = 6-cylinder
A = Gasoline, Aluminum block
1 = Engine Series
3 = Engine Model
Mitsubishi Engine Code Reference Chart
4D55 - 2.3L. Found in Galant 2.3 TD (A167) as well as Pajero (Shogun) 2.3 TD
4D56 - 2.5L. Used in Pajero (Shogun) 2.5 TD (L049G)
4D65 - 1.8L. Found in Galant 1.8 TD (E34A)
4D68 - 2.0L, 1998cc
4G11 - 1.2L, 1244cc
4G12 - 1.4L, 1410cc
4G13 - 1.3L, 1248cc
4G15 - 1.5L, 1468cc
4G16 - 1.2L, 1198cc
4G18 - 1.6L, 1583cc
4G30 - 1.3L, 1298cc
4G31 - 1.5L, 1499cc
4G32 - 1.6L, 1597cc
4G33 - 1.4L, 1439cc
4G35 - 1.7L, 1686cc
4G36 - 1.2L, 1238cc
4G37 - 1.8L, 1755cc
4G41 - 1.4L, 1378cc
4G42 - 1.2L, 1187cc
4G51 - 1.9L, 1855cc
4G52 - 2.0L, 1995cc
4G53 - 2.4L, 2384cc
4G54 - 2.6L, 2555cc
4G61 - 1.6L, 1597cc. Came available with turbo and naturally aspirated versions. Most are DOHC, but apparently SOHC versions were used.
4G62 - 1.8L, 1795cc
4G63 - 2.0L, 1997cc. Came available with turbo and naturally aspirated versions. Most are DOHC, but apparently SOHC versions were used.
4G64 - 2.4L. Mostly available as a SOHC, there are DOHC versions available.
4G67 - 1.8L, 1836cc
4G69 - 2.4L. Motor is a SOHC MIVEC
4G92 - 1.6L, 1597cc. Known commonly for it's DOHC MIVEC version used in the Mirage.
4G93 - 1.8L, 1834cc. Available as a non-turbo SOCH and DOHC. DOHC turbo version was available in '92+ Lancer GSR.
4G94 - 2.0L. Newer SOHC motor used in the Lancer.
6A10 - 1.6L
6A11 - 1.8L
6A12 - 2.0L. Mostly known to be a DOHC MIVEC used in the FTO. Was also availabe in a twin-turbo version in the early 7G Galant VR-4's.
6A13 - 2.5L. Was commonly a DOHC twin-turbo motor used in the more modern 7G and 8G Galant VR-4's.
6G71 - 2.0L, 1998cc. Only known variant is SOHC and supercharged.
6G72 - 3.0L, 2972cc. This motor came in various forms, including SOHC and DOHC naturally aspirated versions. A DOHC twin-turbo version was also available in the 3000GT/GTO VR-4.
6G73 - 2.5L, 2497cc. Available naturally aspirated in SOHC and DOHC form.
6G74 - 3.5L. Available naturally aspirated in SOHC and DOHC form.
6G75 - 3.8L. Available naturally aspirated in SOHC and DOHC form.
G15B - 1.5L SOHC 12v Carb found in early Mirage and Precis.
G32B - 1.6L. Came as a SOHC turbo.
G54B - 2.6L. Found in early Montero and Truck.
G62B - 1.8L. Came as a SOHC turbo.
G63B - 2.0L. Came as a SOHC sometimes with turbo. Found in JDM Starion as well as the Cordia and Tredia.
G63B - 2.4L. SOHC found on the early Galant and Expo.
Credit to: Enjoku, Colt-R, DEVILScarRED