A UK-market Evo known as the FQ400 had a 400 bhp (298 kW; 406 PS) version of the Sirius, making it the most powerful car ever sold by Mitsubishi.

This engine was always DOHC 16-valve and used either Multi-point (MPFI) or Electronic Control (ECFI) fuel injection.

It was available either in carburetor form, multi-point fuel injection, or ECI Turbo as found in the Lancer EX 1800GSR or 1800GT, and Cordia GSR.

As fitted to the fifth generation Galant 200 PS (147 kW; 197 bhp) JIS gross were claimed — the output claims later shrank to 170 PS (125 kW; 168 bhp) — for the turbocharged and intercooled "Sirius Dash 3x2 valve" engine.

This version could switch between breathing through two or three valves per cylinder, to combine high top-end power with low-end drivability as well as allowing for economical operation.

[1] It was a modification of Mitsubishi MCA-Jet technology which used a secondary intake valve to inject air into the engine for more efficient emissions control.

The DOHC version was introduced in 1987 in the Japanese market Galant, and came in turbocharged or naturally aspirated form.

A SOHC carbureted eight-valve version (engine code G63B) was also available in Mitsubishi's pickup trucks (L200, Strada, Mighty Max, Dodge Ram 50) from the eighties until the mid-nineties.

Also, a SOHC version was produced until the late 90s and early 2000s and was used in Mitsubishi cars like the Montero and the 2.0 L 2-door Pajero with an output of 101 kW (137 PS; 135 bhp) at 4700 rpm.

Also the N33 and N83 Space Wagons and Galant (UK market) received the 4G63, in single-cam sixteen-valve format.

It uses multi-point fuel injection, has four valves per cylinder, is turbocharged and intercooled and features forged steel connecting rods.

This version also had a revised turbocharger, extended reach spark plugs, two-piece rings.

A SOHC 16 valve turbocharged version called 4G63S4T is produced by Shenyang Aerospace Mitsubishi Motors Engine Manufacturing (SAME) in Shenyang, China, producing a peak power of 130 kW (174 hp; 177 PS) and a peak torque of 253 N⋅m (187 lb⋅ft) for most applications, and rated 140 kW (188 hp; 190 PS) in some applications.

It was available either naturally aspirated or turbocharged (with an air-to-air intercooler), and was used in most Mitsubishi diesel passenger cars in the eighties and beginning of the nineties.

It was developed specifically to be transversally installed in front-wheel-drive cars, unlike the preceding 4D5-series which remained in production for commercial vehicles.

The 1.8 TD power figures are comparable to those of the 22 percent larger, 2.3 liter 4D55, with more low-down torque and while being much smoother.

[6] The cast-iron block was typical for Mitsubishi, but unusual for diesel engines, in being equipped with balance shafts.

A SOHC 16 valve turbocharged engine similar to 4G63S4T, produced by SAME in Shenyang, China, utilizing a 4G63 shortblock destroked to a displacement of 1.8 L; 109.7 cu in (1,798 cc).

Combustion chambers and piston surfaces were re-engineered to improve fuel economy by lowering friction.