The 4AGE is a 1600cc, 4 cylinder Toyota engine, first built in 1982. It has appeared in many Toyota cars, notably the AE86 Levin and Trueno, the AW11 MR2 and the FXGT Corolla. The engine is a high revving twin cam with excellent response throughout the rev range, and due to its low cost is a popular engine for modifiers and racers. The 4AGE comes in several different flavours, as the engine has slowly evolved.
Blue Top:
Name derived from the blue lettering on the cam covers. The earliest 4AGE’s were mostly blue top. 3 rib block with 16v head, multi point fuel injection (one injector per cylinder) 8 exhaust ports, 8 intake ports and TVIS. TVIS stands for Toyota Variable Induction System, where a set of butterflies were placed across the secondary intake ports. At lower revs, the butterflies were closed to effectively provide 4 intake ports, allowing faster air movement, which results in quicker response. At higher revs, the butterflies opened, allowing all 8 intake ports air, allowing a larger volume of air to enter the engine, resulting in more power. With this TVIS configuration, the engine was highly responsive and economical at low revs, but still had plenty of power at higher revs. 9.4/1 compression ratio.120-130hp at 6600rpm with 14.5 -15.2kg/cm torque. Figures varied between countries due to variation in emissions laws.
Red Top:
Red lettering on the cam covers. Also known as the small port engine. 7 rib block, 16v head, 8 exhaust and 8 inlet ports (only 4 ports on the side of the head and 4 runners from intake manifold. These later split up further into the head). Multi point fuel injection (one injector per cylinder). Known as the small port as the ports in the side of the head had a smaller area than the sum area of the 2 ports on the side of the blue top engine. Higher compression ratio (10.3/1). More power from this engine, but slightly less responsive. This model had oil squirters to each piston and a stronger block. 140hp at 7200rpm with 15.0 kg/cm torque.
20 Valve:
The latest model of 4AGE. Also known as black top or silver top. 7 rib block, 20v head, 8 exhaust and 12 intake ports (4 on side of head, later joined up in head). Multi point fuel injection (one injector per cylinder). This final evolution of the 4AGE featured 5 valves per cylinder, variable intake cam timing (VVT), and quad throttles. The quad throttles and variable cam timing make this engine massively responsive, and is also the most powerful engine in the 4AGE series.160hp at 7400rpm with 16.5 kg/cm torque. Later model had 165hp at 7800rpm and 16.5 kg/cm torque.
These engines appeared in most of Toyota’s compact performance cars between 1984 and up to 1996 with the 20valve engine. A carburettored version of the 4AGE small port was used in Formula Atlantic race cars, some of them reputed to make an impressive 240+hp from a 1600cc 4 cylinder engine, normally aspirated.
A close cousin to the 4AGE is the 4AGZE, a 16v supercharged engine, seen in AW11 MR2s and GTZ Levins and Truenos.
Reference:
http://www.club4ag.com/