The Honda G series engine is an inline 5 cylinder gasoline engine, originally used in the 1992 Acura Vigor

Acura Vigor

The Honda Vigor is a compact sedan sold in Japan from 1981 to 1995. It was sold in North America from 1992 to 1994 as the Acura Vigor, a mid-size luxury car. It was replaced in North America with the Acura TL and in Japan with the Honda Saber...

, Honda Rafaga

Honda Rafaga

The ' series CE4 and CE5 was an intermediate 4 door sedan sold only in Japan by Honda, and used the same 5 cylinder engine that was used in the Honda Inspire and the Honda Vigor and shared a platform with the Honda Ascot. "Rafaga" is Spanish for "gust" or "blustery". The engine is installed...

, Honda Ascot

Honda Ascot

The Honda Ascot was an intermediate saloon car manufactured by Honda and marketed in Japan only from 1989 to 1997. There were two generations of the car, based on the contemporary Honda Accord and Honda Inspire, respectively...

 and Honda Inspire

Honda Inspire

The Honda Inspire is a luxury sedan introduced by Honda in 1990 and based on the Honda Accord chassis. The first Inspire debuted in 1990 as the Accord Inspire, a sister nameplate to the Honda Vigor, then the Honda Vigor was exported to the USA as an Acura...

. It carried over to the Vigor's successor the 2.5TL, which ran from 1995-1998.

Some people colloquially refer to an F-Series

Honda F engine

The Honda F-Series engine was Honda's "big block" SOHC inline four, though lower production DOHC versions of the F-series were built. It features an aluminum open deck cast iron sleeved block and aluminum/magnesium cylinder head...

 block

Cylinder block

A cylinder block is an integrated structure comprising the cylinder of a reciprocating engine and often some or all of their associated surrounding structures...

 (found in Accords) with an H-Series

Honda H engine

The Honda H engine was Honda's high-performance engine family from the 1990s and early 2000s. It is largely derived from the Honda F engine with which it shares many design features. Like Honda's other 4-cylinder families of the 80s and 90s, it was replaced by the Honda K engine...

 head

Cylinder head

In an internal combustion engine, the cylinder head sits above the cylinders on top of the cylinder block. It closes in the top of the cylinder, forming the combustion chamber. This joint is sealed by a head gasket...

 (found in Preludes) as a "G series" engine. This combination of an Accord

Honda Accord

The Honda Accord is a series of compact, mid-size and full-size automobiles manufactured by Honda since 1976, and sold in a majority of automotive markets throughout the world....

 bottom end with a Prelude

Honda Prelude

The Honda Prelude was a sports coupe produced by Japanese automaker Honda from 1978 until 2001. It replaced the Honda S800, a front-engined, front wheel drive sports car...

 head has nothing in common with the actual G-series engine. The engine is longitudinally

Longitudinal engine

In automotive engineering, a longitudinal engine is an internal combustion engine in which the crankshaft is oriented along the long axis of the vehicle, front to back....

 mounted and resembles an F-Series single cam engine (found in early Accords) with an extra cylinder on it and a shorter stroke.

Specifications

• Type: In-line 5 cylinder, aluminum block and head
• Valve Configuration: SOHC, with 4 valves per cylinder

G20A

• Displacement: 1996 cc
• Bore: 82 mm (3.2 in)
• Stroke: 85.6 mm (3.4 in)
• Compression ratio: 9.3:1
• Max Power: 131kw @ 6700 rpm
• Max Torque: 137 ft.lbf @4000

Found in the 1989-1991 JDM Inspire/Vigor (CB5), 1992-1994 JDM Inspire/Vigor 20 (CC3), 1993-1997 JDM Ascot/Rafaga 2.0 (CE4), and 1995-1997 JDM Inspire/Saber 20 (UA1).
G25A

• Displacement: 2451 cc
• Bore: 85 mm (3.3 in)
• Stroke: 86.4 mm (3.4 in)
• Compression ratio: 9.3:1
• Max Power: 177.5 hp (131 kW) @ 6500 rpm
• Max Torque: 166 ft.lbf @3800
• Redline: 6800 rpm
• Fuel Cutoff: 7100 rpm

Found in the 1992-1994 JDM Inspire/Vigor 25 (CC2), 1993-1997 Ascot/Rafaga 2.5S (CE5), and 1995-1997 JDM Inspire/Saber 25 (UA2).
G25A1

• Compression ratio: 9.0:1

Found in the 1992-1994 USDM & CDM Acura Vigor (CC2).

G25A4

• Compression ratio: 9.6:1

Found in the 1995-1998 USDM & CDM Acura 2.5TL (UA2).