This engine series also features 4 valves per cylinder, forged steel connecting rods and crankshaft, one-piece cast camshafts, a timing chain,[1] and a cast aluminium lower intake manifold.

The GR series replaces the previous MZ V6 and JZ inline-6, and in the case of light trucks the VZ V6.

This engine features Toyota's VVT-i, variable valve timing system on the intake cam and a compression ratio of 10.0:1.

For increased cooling efficiency, the 1GR employs water passages between the bores of the engine.

A bolt-on TRD supercharger kit was available on the Tacoma and FJ Cruiser but has been discontinued by Toyota.

The new 2015 Toyota HiLux receives a slightly different version of the single VVT-i engine, with the only change being a removal of an air intake baffle tank being replaced by a conventional air filter housing to intake pipe to surge tank style.

First generation 1GR-FE variants with single VVT-i features Toyota's Acoustic Control Induction System.

[3] This version features Toyota's Dual VVT-i, variable valve timing on both the intake and exhaust cams.

Valves are driven by roller-follower rocker arms with low friction roller bearings, and a unique, concave cam lobe design to increase valve lift over the traditional shimless lifter type system of the 1GR-FE.

This increases overall cylinder head height to accommodate the slightly taller roller rocker system.

Direct injection lowers the tendency to knock (detonation) and increases performance by reducing the charge intake temperature.

These are in place to help achieve a homogeneous air-fuel mixture inside the cylinder at low RPM and high load, but these mechanisms inhibit performance at higher engine speeds.

In the 2GR-FSE, port injection is used considerably to achieve the correct mixture without having in-engine restrictions, meaning the engine achieves specific power near the top of all naturally aspirated production gasoline engines in the world (68 kW (92.5 PS; 91.2 hp)/L, 234 kW (318 PS; 314 hp) in the Mark X).

The dual fan spray pattern of the direct injectors is perpendicular to the piston travel with wide dispersion in the cylinder, which aids air and fuel mixture and therefore increases power and efficiency.

[7][8][9][10] Applications (calendar years): Supercharged: Atkinson cycle, VVT-i, uses cooled EGR system.

Applications (calendar years; net combined horsepower listed): The 3GR-FE is a 3.0 L (2,994 cc) version with Dual VVT-i, designed for RWD longitudinal mounting.

This version also features Dual VVT-i, variable valve timing on both the intake and exhaust cams and an improved D4 direct injection system.

The 8GR-FXS uses a similar fuel setup to the 2GR-FKS, combining the D-4S system and the simulated on-demand Atkinson cycle used in the 2UR-GSE and 8AR-FTS engines.