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Honda G engine
Honda G engine
Honda G engine
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Honda G engine
Overview
ManufacturerHonda Motor Manufacturing
Production1989–1998
Layout
ConfigurationNaturally aspirated inline-5
Displacement2.0–2.5 L; 121.8–149.6 cu in (1,996–2,451 cc)
Cylinder bore82 mm (3.23 in)
85 mm (3.35 in)
Piston stroke75.6 mm (2.98 in)
86.4 mm (3.40 in)
Cylinder block materialAluminum
Cylinder head materialAluminum
ValvetrainSOHC 4 valves x cyl.
Compression ratio9.0:1-10.0:1
RPM range
Max. engine speed6800
Combustion
Fuel systemFuel injection
Fuel typeGasoline
Cooling systemWater-cooled
Output
Power output114–140 kW (155–190 PS; 153–188 hp)
Torque output19–24.2 kg⋅m (186–237 N⋅m; 137–175 lb⋅ft)

The Honda G-series engine is a family of slanted inline-five cylinder gasoline engines. The engine family features a single overhead cam layout with 4 valves per cylinder. The engine's displacement varied from 2.0 L; 121.8 cu in (1,996 cc) to 2.5 L; 149.6 cu in (2,451 cc). The G-Series was originally used in the 1989 Honda Vigor, Honda Rafaga, Honda Ascot and Honda Inspire before being carried over to the Vigor's successor; the Acura TL, which used the G-Series family of engines from 1995 to 1998 in North America, and continued use in the JDM Honda Saber until 1998 as well.

G20A

[edit]
  • Displacement: 2.0 L; 121.8 cu in (1,996 cc)
  • Bore x Stroke: 82 mm × 75.6 mm (3.23 in × 2.98 in)
  • Compression ratio: 9.7:1
  • Max Power: 114–118 kW (155–160 PS; 153–158 hp) @ 6700 rpm
  • Max Torque: 19 kg⋅m (186 N⋅m; 137 lb⋅ft) @ 4000 rpm
  • Redline: 6800 rpm
  • Fuel Cutoff: 7100 rpm

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

[edit]
  • Displacement: 2.5 L; 149.6 cu in (2,451 cc)
  • Bore x Stroke: 85 mm × 86.4 mm (3.35 in × 3.40 in)
  • Compression ratio: 10.0:1
  • Max Power: 140 kW (190 PS; 188 hp) @ 6500 rpm
  • Max Torque: 24.2 kg⋅m (237 N⋅m; 175 lb⋅ft) @3800 rpm
  • 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

[edit]
  • Compression ratio: 9.0:1

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

G25A4

[edit]
  • Compression ratio: 9.6:1

Power: 176 hp (131 kW; 178 PS)

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

[edit]
  • Front view
    Front view
  • Top view
    Top view
  • Left view
    Left view
  • Right view
    Right view

References

[edit]
Revisions and contributorsEdit on WikipediaRead on Wikipedia

Honda G engine

View on Grokipedia
from Grokipedia
The Honda G engine, formally known as the G-series, is a family of slanted inline-five-cylinder engines produced by Motor Company from 1989 to 1998. These engines feature a single overhead (SOHC) layout with four valves per cylinder, an aluminum block and head, and a longitudinal mounting orientation designed for front-wheel-drive vehicles to achieve balanced . Primarily developed for mid-size sedans, the G-series represented Honda's rare experiment with five-cylinder architecture, derived from extending the existing F-series four-cylinder design by adding one cylinder. Introduced in 1989 with the Japanese-market Honda Vigor (also known as the Inspire in some regions), the G-series debuted amid Japan's automotive boom and Honda's diversification efforts. The lineup included two main variants: the 2.0-liter G20A, with a displacement of 1,996 cc, bore and stroke of 82.0 mm × 75.6 mm, compression ratio of 9.7:1, and output of 153–158 horsepower at 6,700 rpm and 137 lb-ft of torque at 4,000 rpm; and the 2.5-liter G25A, with 2,451 cc displacement, bore and stroke of 85.0 mm × 86.4 mm, compression ratio of 9.0–10.0:1 (varying by market), and power ranging from 176–188 horsepower at 6,300–6,500 rpm and 170–175 lb-ft of torque at 3,800–3,900 rpm. Fuel-injected and without Honda's signature VTEC variable valve timing, these engines emphasized smooth operation through electronically adjustable hydraulic mounts and a redline up to 6,800 rpm, though they lacked the high-revving character of other Honda powerplants. The G-series powered a select range of upscale sedans, including the Ascot, Rafaga, and Inspire in from 1989 to 1997, as well as the North American Vigor (1992–1994) and first-generation (1996–1998). Despite offering sportier handling potential due to the engine's positioning—three cylinders forward of the front axle and two behind for near 50/50 weight balance—the series achieved limited commercial success, hampered by conservative vehicle styling, higher pricing compared to four-cylinder rivals, and competition from more powerful V6 options. Production ended in 1998 as shifted focus to transverse V6 engines like the J-series for broader market appeal and efficiency, marking the G-series as a short-lived footnote in the company's engine history.

Overview

Engine Family Description

The Honda G engine represents Honda's sole production inline-5 engine family, naturally aspirated and developed exclusively for automotive applications. Produced from 1989 to 1998, this family marked a unique departure from Honda's predominant inline-4 and V6 configurations, emphasizing refinement in higher-end models. The engines feature a slanted inline-5 layout with a single overhead (SOHC) and four valves per , constructed from an aluminum block and head for lightweight construction. They are water-cooled and equipped with electronic to ensure efficient operation and emissions compliance. Displacement spans 2.0 L to 2.5 L (1,996–2,451 cc), delivering general power outputs of 114–140 kW (153–188 hp) and of 186–237 N⋅m, with a maximum engine speed reaching up to 6,800 rpm across variants. Designed for smooth, refined performance in mid-size luxury sedans, the G engine family aimed to bridge the gap between the efficiency of inline-4 engines and the inherent smoothness of inline-6 designs, while offering reduced vibration inherent to the odd-cylinder inline-5 architecture.

Key Specifications

The Honda G engine family employs a ranging from 9.0:1 to 10.0:1, enabling balanced performance and tailored to various regional requirements. All variants feature Honda's (PGM-FI) system, a multi-point electronic setup that delivers precise air-fuel mixtures for consistent power output and reduced emissions. The engines utilize with aluminum alloy construction for the block and , promoting effective heat dissipation while minimizing overall mass for better .
SpecificationDetail
6800 rpm
1-2-4-5-3
Emissions ComplianceJapanese and US EPA standards (1989–1998)
Block Slant Angle~35 degrees (for longitudinal FWD packaging)
The single overhead camshaft (SOHC) configuration supports reliable operation and emphasizes low-end delivery.

Development and Design

Historical Development

The G-series engine family originated in the late 1980s as part of the company's strategy to expand into premium mid-size sedans, offering an alternative to V6 configurations while optimizing for front-wheel-drive platforms. Developed primarily for the Japanese market, the inline-five was pursued to deliver enhanced refinement and balance akin to an inline-six, but in a more compact package that avoided the added length and complexity of a six-cylinder layout. This approach addressed growing demand for smoother, quieter powertrains in upscale vehicles like the and Vigor, positioning against competitors in and . Key milestones began with the engine's debut in October 1989, powering the first-generation (CB5/CC3) and its badge-engineered counterpart, the (CB5), both featuring the initial 2.0-liter G20A variant. The lineup evolved in 1992 with the introduction of the larger 2.5-liter G25A for higher-performance models, such as the updated Inspire (CC2), which provided increased torque and refinement for executive-oriented sedans. These developments reflected Honda's iterative focus on reducing (NVH) through targeted engineering, as detailed in early research on resonance mitigation. Production of the G-series occurred at Honda's facilities in , with export units supporting North American models like the Vigor introduced in 1992. The inline-five layout remained rare among Japanese automakers, with Honda's implementation standing out for its longitudinal mounting in front-wheel-drive applications. Manufacturing concluded in 1998, coinciding with the broader transition to the more versatile V6 J-series engines across Honda's sedan lineup, marking the end of the G-series' brief but innovative tenure.

Architectural Features

The Honda G engine employs a slanted inline-five cylinder layout, oriented longitudinally in front-wheel-drive vehicles to optimize packaging within the while providing a smoother power delivery than a four-cylinder counterpart. This configuration reduces the engine's overall length compared to a straight inline-six, allowing for better integration into compact sedan platforms without compromising displacement or performance. The features a single overhead (SOHC) layout, driven by a timing belt, with four valves per to enhance , , and power output across the rev range. This design prioritizes reliability and low maintenance, characteristic of Honda's engineering approach in the late 1980s and early 1990s. The are arranged in a of 1-2-4-5-3, which helps mitigate secondary imbalances inherent to odd-numbered inline configurations through balanced throws. The is constructed from lightweight aluminum with cast-iron sleeves, balancing weight reduction for improved vehicle handling and economy with enhanced durability under high loads. The G series represents Honda's inaugural automotive application of an inline-five architecture, engineered specifically for robust low-end peaking around 3800–4000 rpm to suit everyday driving dynamics. The (PGM-FI) system supports low emissions while complementing the engine's efficient breathing characteristics.

Variants

G20A

The G20A is the 2.0-liter inline-five-cylinder variant of the Honda G engine family, produced from 1989 to 1998. It features a displacement of 1,996 cc, achieved through a bore of 82 mm and a of 75.6 mm. The engine employs a of 9.7:1, contributing to its balanced performance characteristics. In terms of output, the G20A delivers between 114 kW and 118 kW (153 hp to 158 hp) at 6,700 rpm, with peak torque of 186 N⋅m (137 lb⋅ft) at 4,000 rpm. Its is set at 6,800 rpm, with fuel cutoff at 7,100 rpm. Introduced in , this engine was positioned as the base powerplant for entry-level configurations within Honda's mid-size sedan lineup, emphasizing reliability and everyday usability. The G20A was specifically tuned for improved fuel economy, running on regular unleaded gasoline to reduce operating costs for consumers. Compared to the larger 2.5 L G25A variant, its smaller displacement provided better efficiency without sacrificing the smooth power delivery inherent to the G-series architecture. It found application in 20-series models, such as those designated with the "20G" code, and notably lacks any subvariants, maintaining a uniform specification throughout its production run. Sharing the family's single overhead camshaft (SOHC) design with four valves per cylinder, the G20A ensured design consistency and ease of maintenance across the engine lineup.

G25A

The G25A is the 2.5-liter variant of the Honda G engine family, offering a displacement of 2,451 cc achieved through a bore of 85 mm and a stroke of 86.4 mm. This larger displacement compared to the 2.0-liter G20A provides premium power delivery suited for higher-performance applications, with the engine's slanted inline-five layout facilitating compact packaging in front-wheel-drive vehicles. The base configuration features a of 10.0:1, delivering 140 kW (188 hp) at 6,500 rpm and 237 N⋅m (175 lb⋅ft) at 3,800 rpm. The G25A1 subvariant was specifically tuned for North American markets, incorporating a lower of 9.0:1 to accommodate lower-octane fuels available in the and . This detuned setup, used from 1992 to 1994, produces 131 kW (176 hp) at 6,300 rpm and 231 N⋅m (170 lb⋅ft) at 3,900 rpm while maintaining the core SOHC 20-valve architecture. The G25A4 subvariant, introduced for 1995–1998 models, refines the design with a 9.6:1 and enhancements for improved emissions compliance, including updated fuel mapping. It outputs 131 kW (176 hp) at 6,300 rpm and 231 N⋅m (170 lb⋅ft) at 3,900 rpm, with later iterations featuring variable intake geometry via a dual-stage induction system to broaden the band across operating ranges.

Applications

Japanese Domestic Market Models

The Honda G engine family found its primary applications in (JDM) luxury sedans, where it was paired with either a 5-speed manual or 4-speed to deliver smooth, refined highway performance suited to executive vehicles. From 1989 to 1994, the G-series powered the first-generation /Vigor (chassis codes CB5, CC2, and CC3), with the 2.0-liter G20A fitted to base trims and the 2.5-liter G25A reserved for higher-end variants, offering outputs up to 180 PS for enhanced cruising capability. The engine continued in the 1993–1997 Honda Ascot/Rafaga (CE4/CE5), where the G20A served the 2.0-liter models and the G25A equipped the sportier 2.5S trim, achieving 160–190 PS depending on configuration and contributing to the sedan's agile handling in urban and expressway settings. In the 1995–1997 second-generation lineup, the G20A powered the 20-series trims of the /Saber (UA1/UA2), while the G25A drove the 25-series, with power ratings from 160 PS to 190 PS and a focus on quiet, vibration-free operation for premium JDM buyers. These applications represented high-volume production for in , with the Inspire alone exceeding 100,000 units across its G-engine generations, underscoring the engine's role in elevating the brand's position in the domestic luxury segment.

Export Market Models

The G engine found its primary export applications in North American markets through Acura's premium lineup, with no notable adoption in , beyond , or other regions. The 1992–1994 Acura Vigor sedan (CC2 chassis), sold in the United States and , exclusively utilized the G25A1 variant. This detuned iteration produced 176 horsepower at 6300 rpm and 170 lb-ft of torque at 3900 rpm, featuring a reduced of 9.0:1 optimized for the 87-octane fuel commonly available in . The engine's longitudinal mounting contributed to balanced handling, and it was mated to either a 5-speed manual or 4-speed , aligning with 's emphasis on refined luxury in the entry-level executive segment. The Vigor's successor, the 1996–1998 2.5 TL (UA2 chassis), also exclusive to the and Canadian markets, employed the G25A4 variant with the same output of 176 horsepower at 6300 rpm and 170 lb-ft of torque at 3900 rpm, but with a higher of 9.6:1 and refinements including a dual-stage manifold for improved mid-range response. These updates ensured compliance with evolving emissions standards, incorporating (PGM-FI) and OBD-II diagnostics starting in 1996, while retaining the 5-speed manual or 4-speed automatic transmission options to support 's sport-luxury positioning. In reviews, the G engine's applications were lauded for their smooth, vibration-free power delivery and distinctive inline-five character, providing a premium feel superior to many four-cylinder rivals, though acceleration was occasionally critiqued as adequate but less potent than V6-equipped competitors like the or .

References

  1. https://www.drivingline.com/articles/engine-oddity-looking-back-on-hondas-short-lived-inline-five-cylinder/
  2. https://www.nthefastlane.com/honda-g-series-engine-specs-info
  3. https://www.caranddriver.com/features/g15087001/five-alive-all-the-notable-cars-we-know-with-five-cylinder-engines/
  4. https://www.jalopnik.com/forgotten-cars-hondas-long-lost-five-cylinder-engine-a-5981238
  5. https://automacha.com/did-you-know-honda-once-made-a-5-cylinder-engine/
  6. https://www.jalopnik.com/forgotten-cars-hondas-long-lost-five-cylinder-engine-a-5981238/
  7. https://hondanews.com/en-US/releases/release-6270298192770c9498256e004c34c0f5-1993-acura-vigor-specifications
  8. https://www.automoli.com/us/vehicles/honda/inspire/inspire-i-cb5cc2cc3-9184/
  9. https://carbuzz.com/best-honda-engine-families-ever-made/
  10. https://www.sae.org/papers/honda-new-line-five-cylinder-engine-noise-vibration-reduction-900389/
  11. https://www.enginelabs.com/engine-tech/engine/gimme-5-how-the-inline-five-cylinder-engine-works-and-doesnt/
  12. https://engines.honda.com/why/technology
  13. https://mymotorlist.com/engines/honda/g20a/
  14. https://autostatistics.net/honda/engines/g20a
  15. https://www.automobile-catalog.com/car/1989/1103990/honda_inspire_accord_az-i_automatic.html
  16. https://en.avtotachki.com/dvigatel-honda-g20a/
  17. https://garimoto.net/catelog/cars/specification/model/year/Japan/HONDA/VIGOR
  18. https://www.automobile-catalog.com/car/1994/1105430/honda_inspire_25gi.html
  19. https://www.motortrend.com/features/1992-1994-acura-vigor-history-specs-photos
  20. https://www.ultimatespecs.com/car-specs/Acura/124566/Acura-Vigor-25i.html
  21. https://acuranews.com/en-US/releases/release-c72fc73f8c7eb38560e69e004c34c077-acura-model-chronology-1992-1994-vigor-sedan
  22. https://hondanews.com/en-US/releases/release-41eb121dcc8c3cc009807d004c34c974-1998-acura-3-2-and-2-5-tl-specifications
  23. https://www.carfolio.com/honda-inspire-25s-601843
  24. https://www.carfolio.com/honda-ascot-rafaga-2.5s-191345
  25. https://www.carfolio.com/honda-inspire-25g-601964
  26. https://www.carfolio.com/honda-accord-inspire-ax-i-604934
  27. https://www.carfolio.com/honda-ascot-rafaga-2.0t-191279
  28. https://www.carfolio.com/honda-saber-25s-601854
  29. https://www.carfolio.com/honda-inspire-20g-601711
  30. https://fisherdiscount.com/blogs/news/hondas-attempt-at-luxury-midsize-cars-the-first-generation-inspire
  31. https://acuranews.com/en-US/releases/release-8aeca99775b6beb6bab0cc004c34c9cf-1996-acura-tl-powertrain
  32. http://owners.acura.com/Documentum/Warranty/Handbooks/E2191.pdf
  33. https://www.caranddriver.com/reviews/a45701807/1991-acura-audi-infiniti-mitsubishi-nissan-subaru-sports-sedans-archive-comparison-test/
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