Honda C engine
Encyclopedia
Honda
is a Japanese public multinational corporation primarily known as a manufacturer of automobiles and motorcycles.Honda has been the world's largest motorcycle manufacturer since 1959, as well as the world's largest manufacturer of internal combustion engines measured by volume, producing more than...
's first production V6 was the C series; it was produced in displacements from 2.0 liters to 3.5 liters. The C engine was produced in various forms for over 20 years (1985 - 2005)
All C engines share in common a 90 degree V from bank to bank. Beyond this fact there is little to no similarity between the three drive train layouts. The engine family can be broken down into three sub families:
- C20A, C20AT, C25A and C27A (transversely mounted)
- C30A and C32B (transversely mounted rear)
- C32A, C35A, and C35B (one-off) (longitudinally mounted)
As a general rule, interchange of parts will not work between these sub groups.
C20A
SOHC 2.0 L (1,996 cc) @ 6,500 rpm @ 5,500 rpmJapan only:
- 1986–1988 Honda Legend
- Experimental HP-X (Honda Pininfarina Xperimental)
The variable length intake manifold
Variable Length Intake Manifold
In internal combustion engines, a variable length intake manifold , or variable intake manifold is an automobile internal combustion engine manifold technology...
used six individual small-bore intake runners below 3,500 rpm for each cylinder and added an additional six individual larger bore intake runners at higher RPMs.
The C20AT was a turbocharged version, called the "Wing Turbo", producing 190 bhp.
Japan only:
- 1989 Honda Legend
Honda replaced the variable length intake manifold with a variable geometry turbocharger
Variable geometry turbocharger
Variable-geometry turbochargers are a family of turbochargers, usually designed to allow the effective aspect ratio of the turbo to be altered as conditions change. This is done because optimum aspect ratio at low engine speeds is very different from that at high engine speeds...
to the C20A engine used in the Japanese Domestic Market Legend. The turbo with intercooler-equipped engine was the C20AT engine and are extremely rare. Honda pioneered variable-geometry turbo chargers. The "Wing Turbo", as Honda called them, were controlled by an 8-bit processor ECU
Electronic control unit
In automotive electronics, electronic control unit is a generic term for any embedded system that controls one or more of the electrical systems or subsystems in a motor vehicle....
and they were constantly adjusting. Basically, at low speeds the wings surrounding the turbine wheel inside the compressor housing on the intake side would be nearly closed to speed and direct exhaust pressure precisely on the turbine wheel. At 2000 rpm, the wings would fluctuate and it would act like a much larger turbo to increase fuel economy as needed. This car was quick and powerful, but the price premium over the slightly longer and wider Legend with the 2.7 L naturally aspirated V6 was too much for most, so the car disappeared. This was one of the only production Hondas ever turbocharged from the factory, along with the K23A1 straight-4 engine used in the Acura RDX
Acura RDX
The Acura RDX is Acura’s first compact crossover SUV. Originally previewed as the Acura RD-X concept car, the production RDX had its debut at the 2006 New York Auto Show and went on sale on August 11, 2006....
and the ER straight-4 engine used in the first generation Honda City
Honda City
The Honda City is a subcompact car manufactured by the Japanese manufacturer Honda since 1981. Originally made for the Japanese, European and Australasian markets, the City was retired without replacement in 1994...
.
C25A
SOHC 24 valves, 9.0:1 compressionJapan @ 6,000 rpm @ 4,500 rpm
North America:
- 1986-1987 Honda LegendHonda LegendThe Honda Legend is a mid-size luxury car made by the Japanese automaker Honda. It was the result of Project XX, a joint agreement started in November 1981 with the Austin Rover Group of Great Britain and was mechanically related to the Rover 800 series....
Sedan, 1986-1988 Rover 825 Sedan,- 151 bhp @ 5,800 rpm
- 21.7 kgm @ 4,500 rpm
- UK and Europe (sold in US as Sterling 825iSterling (car)Sterling was a brand name of automobile marketed in the USA by ARCONA, Austin Rover Cars Of North America under the name Sterling Motor Cars, a division of the Rover car company of the UK...
)
The engine utilized a 90 degree V-angle to the crankshaft in preference to the taller but more common 60 degree design, with a compression ratio of 9.0:1. The crankshaft had crankpins offset 30 degrees to provide a low profile engine that fires smoothly and evenly. The block and cross flow pent roof cylinder heads with 24 valves are die-cast from aluminum alloy and the cylinder bores are lined with cast iron. The exhaust system uses equal length exhaust pipes connected to the Exhaust manifold to minimize scavenging resistance and maximum total exhaust efficiency. An external high capacity water cooled oil cooler and filter maintain an efficient oil temperature.
C27A
The SOHC C27A is a 2.7 L version, with the major upgrade being the addition of an variable length intake manifoldVariable Length Intake Manifold
In internal combustion engines, a variable length intake manifold , or variable intake manifold is an automobile internal combustion engine manifold technology...
, producing 170 bhp.
Applications; non-North America:
-
- 1988-1990 Honda LegendHonda LegendThe Honda Legend is a mid-size luxury car made by the Japanese automaker Honda. It was the result of Project XX, a joint agreement started in November 1981 with the Austin Rover Group of Great Britain and was mechanically related to the Rover 800 series....
Coupe, 176 hp - 1988-1990 Honda LegendHonda LegendThe Honda Legend is a mid-size luxury car made by the Japanese automaker Honda. It was the result of Project XX, a joint agreement started in November 1981 with the Austin Rover Group of Great Britain and was mechanically related to the Rover 800 series....
Saloon, 176 hp
- 1988-1990 Honda Legend
Applications; North America:
- SOHC non-VTEC
- 1987-1990 Acura LegendAcura LegendThe Acura Legend, sold as the Honda Legend outside the U.S., Canada, and parts of China, was a luxury vehicle sold from 1986 to 1995 as both a sedan and coupe. It was the first flagship sedan sold under the Acura nameplate, until being renamed in 1996 as the Acura 3.5RL. The 3.5RL was North...
Coupe, 161 bhp - 1988-1990 Acura LegendAcura LegendThe Acura Legend, sold as the Honda Legend outside the U.S., Canada, and parts of China, was a luxury vehicle sold from 1986 to 1995 as both a sedan and coupe. It was the first flagship sedan sold under the Acura nameplate, until being renamed in 1996 as the Acura 3.5RL. The 3.5RL was North...
, 161 bhp - 1995-1997 Honda AccordHonda AccordThe 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....
, 170 bhp For this particular vehicle the engine was updated with a more efficient intake manifold. - 1989-1991 Rover 827/Sterling/VitesseRover 800The Rover 800 series is an executive car introduced by the Austin Rover Group in 1986 and also marketed as the Sterling in the United States. Co-developed with Honda, it was a close relative to the Honda Legend and the successor to the Rover SD1....
, 177 bhp (non catalyst)UK and Europe (sold in US as STERLING Brand) - 1990-1991 Rover 827/Sterling/VitesseRover 800The Rover 800 series is an executive car introduced by the Austin Rover Group in 1986 and also marketed as the Sterling in the United States. Co-developed with Honda, it was a close relative to the Honda Legend and the successor to the Rover SD1....
, 168 bhp (catalyst) UK and Europe (sold in US as STERLING Brand until 1991) - 1991-1995 Rover 827/Sterling/CoupeRover 800The Rover 800 series is an executive car introduced by the Austin Rover Group in 1986 and also marketed as the Sterling in the United States. Co-developed with Honda, it was a close relative to the Honda Legend and the successor to the Rover SD1....
, 168 bhp UK and Europe
- 1987-1990 Acura Legend
C30A
The DOHC VTECVTEC
VTEC is a valvetrain system developed by Honda to improve the volumetric efficiency of a four-stroke internal combustion engine. The VTEC system uses two camshaft profiles and electronically selects between the profiles. It was invented by Honda R&D engineer Ikuo Kajitani, and was the first system...
C30A is a 3.0 L version, producing 270 bhp and 210 lbft of torque
Torque
Torque, moment or moment of force , is the tendency of a force to rotate an object about an axis, fulcrum, or pivot. Just as a force is a push or a pull, a torque can be thought of as a twist....
. The engine was the first to utilize Honda's proprietary VTEC
VTEC
VTEC is a valvetrain system developed by Honda to improve the volumetric efficiency of a four-stroke internal combustion engine. The VTEC system uses two camshaft profiles and electronically selects between the profiles. It was invented by Honda R&D engineer Ikuo Kajitani, and was the first system...
variable-valve timing system in an automotive application, which adjusts cam lift and duration depending on engine RPM and throttle position. VTEC allows the C30A to produce a high maximum power level while maintaining a relatively flat torque
Torque
Torque, moment or moment of force , is the tendency of a force to rotate an object about an axis, fulcrum, or pivot. Just as a force is a push or a pull, a torque can be thought of as a twist....
curve.
The C30A also made use of titanium connecting rods, which was another first in a mass-production vehicle. The lightweight rods allowed a higher RPM to be achieved while maintaining the strength of traditional steel rods. The C30A block is an open-deck design made from an aluminum alloy with cylinders sleeved in ductile iron. The heads are a twenty-four valve, dual-overhead cam (DOHC) design and contain the VTEC
VTEC
VTEC is a valvetrain system developed by Honda to improve the volumetric efficiency of a four-stroke internal combustion engine. The VTEC system uses two camshaft profiles and electronically selects between the profiles. It was invented by Honda R&D engineer Ikuo Kajitani, and was the first system...
mechanism, which is actuated by oil pressure. For maximum performance, the C30A uses a direct ignition system, with individual coils
Ignition coil
An ignition coil is an induction coil in an automobile's ignition system which transforms the battery's 12 volts to the thousands of volts needed to create an electric spark in the spark plugs to ignite the fuel...
positioned directly over each cylinder spark plug
Spark plug
A spark plug is an electrical device that fits into the cylinder head of some internal combustion engines and ignites compressed fuels such as aerosol, gasoline, ethanol, and liquefied petroleum gas by means of an electric spark.Spark plugs have an insulated central electrode which is connected by...
.
Due to its DOHC layout and its lighweight rotating assembly, the C30A is capable of reliable high RPM operation. Factory redline is 8000 rpm and balanced/blueprinted versions of the engine can easily reach 9000 rpm with little to no reliability issues.
Due to its complexity, cost and use of exotic materials, the C30A was used exclusively on Honda's NSX
NSX
NSX may refer to:* Namibian Stock Exchange , a stock exchange based in Namibia, Africa* Narrow Shape Cross-Section Blade , a design of ice-skating blade from Diederik Hol...
car. For NSX
NSX
NSX may refer to:* Namibian Stock Exchange , a stock exchange based in Namibia, Africa* Narrow Shape Cross-Section Blade , a design of ice-skating blade from Diederik Hol...
's equipped with a 4-speed automatic transmission, Honda used a slightly less powerful version of the C30A, which utilized less aggressive cam
Cam
A cam is a rotating or sliding piece in a mechanical linkage used especially in transforming rotary motion into linear motion or vice-versa. It is often a part of a rotating wheel or shaft that strikes a lever at one or more points on its circular path...
timing and produced 252 bhp.
An advanced version of this engine exists (though not in a production form) that campaigned briefly in the 2004 Japanese SuperGT racing series (see All Japan Grand Touring Car Championship) by the factory-supported Team Honda Racing group in highly modified GT-spec NSXs. This engine has various upgrades and modifications by Mugen
Mugen Motorsports
Mugen Motorsports is a Japanese company formed in 1973 by Hirotoshi Honda, the son of Honda Motor Company founder Soichiro Honda, and Masao Kimura. Mugen, meaning "Without Limit", or "Unlimited", is an engine tuner and parts manufacturer closely associated with the Honda Motor Company...
and is the first turbo-charged Honda engine used in the series (prior to 2003, the GT-spec NSXs used a highly advanced, naturally aspirated variant of the C32B engine). Though the exact performance figures are kept secret, it is rumored to output more than 500 bhp.
Applications:
- 1991-1996 Honda NSXHonda NSXThe Honda NSX, or Acura NSX, is a sports car that was produced between 1990 and 2005 by the Japanese automaker Honda. It is equipped with a mid-engine, rear-wheel drive layout, powered by an all-aluminium V6 gasoline engine featuring Honda's Variable Valve Timing and Lift Electronic Control ...
5-Speed Manual Transmission - 1991-2005 Honda NSXHonda NSXThe Honda NSX, or Acura NSX, is a sports car that was produced between 1990 and 2005 by the Japanese automaker Honda. It is equipped with a mid-engine, rear-wheel drive layout, powered by an all-aluminium V6 gasoline engine featuring Honda's Variable Valve Timing and Lift Electronic Control ...
4-Speed Automatic Transmission
C32A
The C32A is a 3.2 L version. The SOHC depending on model year, produces 200 and 230 hp (175 kW).Applications; North America Only:
- C32A1 - SOHC USDM - 200 hp (155 kW)
- 1991-1995 Acura LegendAcura LegendThe Acura Legend, sold as the Honda Legend outside the U.S., Canada, and parts of China, was a luxury vehicle sold from 1986 to 1995 as both a sedan and coupe. It was the first flagship sedan sold under the Acura nameplate, until being renamed in 1996 as the Acura 3.5RL. The 3.5RL was North...
sedan - 1991-1992 Acura LegendAcura LegendThe Acura Legend, sold as the Honda Legend outside the U.S., Canada, and parts of China, was a luxury vehicle sold from 1986 to 1995 as both a sedan and coupe. It was the first flagship sedan sold under the Acura nameplate, until being renamed in 1996 as the Acura 3.5RL. The 3.5RL was North...
coupeCoupéA coupé or coupe is a closed car body style , the precise definition of which varies from manufacturer to manufacturer, and over time...
- 1991-1995 Acura Legend
- C32A6 - SOHC USDM - 200 hp (155 kW)
- 1996-1998 Acura 3.2TLAcura TLThe TL "Touring Luxury" debuted as 1996 model, first with the 1996 2.5 TL available with the 2.5 L 176 hp SOHC 20-valve 5-cylinder engine from the Vigor. The 3.2 TL used the 3.2 L 200 hp SOHC 24v V6 from the second generation Acura Legend. The 2.5 TL was positioned as the...
- 1996-1998 Acura 3.2TL
- C32A5 - Also known as the "Type-II" - Uses a higher flowing intake manifold and slightly more aggressive camshaft - SOHC USDM - 230 hp (170 kW) at 206 ft.lbf
- 1994-1995 Acura LegendAcura LegendThe Acura Legend, sold as the Honda Legend outside the U.S., Canada, and parts of China, was a luxury vehicle sold from 1986 to 1995 as both a sedan and coupe. It was the first flagship sedan sold under the Acura nameplate, until being renamed in 1996 as the Acura 3.5RL. The 3.5RL was North...
GS sedan - 1993-1995 Acura LegendAcura LegendThe Acura Legend, sold as the Honda Legend outside the U.S., Canada, and parts of China, was a luxury vehicle sold from 1986 to 1995 as both a sedan and coupe. It was the first flagship sedan sold under the Acura nameplate, until being renamed in 1996 as the Acura 3.5RL. The 3.5RL was North...
LS and L coupe - 1995-1998 Honda InspireHonda InspireThe 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...
/Honda Sabre
- 1994-1995 Acura Legend
C32B
The C32B is a highly tuned DOHC V6 used in the Honda NSXHonda NSX
The Honda NSX, or Acura NSX, is a sports car that was produced between 1990 and 2005 by the Japanese automaker Honda. It is equipped with a mid-engine, rear-wheel drive layout, powered by an all-aluminium V6 gasoline engine featuring Honda's Variable Valve Timing and Lift Electronic Control ...
, which produces 290 hp (216 kW) and 224 lbf•ft (304 N•m). The engine is essentially an update to the C30A and does not share commonality with the C32A. Honda increased displacement to 3.2 l (195 cu in) through the use of larger 93 mm (3.7 in) piston
Piston
A piston is a component of reciprocating engines, reciprocating pumps, gas compressors and pneumatic cylinders, among other similar mechanisms. It is the moving component that is contained by a cylinder and is made gas-tight by piston rings. In an engine, its purpose is to transfer force from...
s over the 90 mm (3.5 in) used in the C30A. To accommodate the larger pistons, Honda used an advanced metallurgical technique on the cylinders called Fiber Reinforced Metal (FRM), in which an ultra lightweight alumina-carbon fiber is cast into the traditional aluminum alloy for enhanced rigidity. This process allowed thinner cylinder walls to be used while providing acceptable cooling characteristics. The C32B also used 32 mm (1.3 in) intake valves, which are 1 mm (0.0393700787401575 in) larger than those in the C30A.
Applications:
- 1997-2005 Honda NSXHonda NSXThe Honda NSX, or Acura NSX, is a sports car that was produced between 1990 and 2005 by the Japanese automaker Honda. It is equipped with a mid-engine, rear-wheel drive layout, powered by an all-aluminium V6 gasoline engine featuring Honda's Variable Valve Timing and Lift Electronic Control ...
6-Speed Manual Transmission
C35A
The C35A is a SOHC and carries the largest displacement of the C series at 3.5 l (213 cu in). The engine is also said to have forged components specifically its crankshaft and connecting rods. The C35 also contains a balance shaft to dampen engine vibrations associated with 90 degree design V6 engines. Besides the addition of these forged components, the overall design is similar to its smaller counter part the C32A, with some parts being interchangeable. The 9.6:1 compression ratio of the C32A is also retained, despite the increase in displacement.Applications:
- C35A - SOHC - 210–225 hp (155–170 kW)
- 1996-2004 Acura 3.5RL (US/Canada) [(210 hp @ 5200 rpm)(224 lbs-ft @ 2800 rpm)]
- 1996-2004 Honda LegendHonda LegendThe Honda Legend is a mid-size luxury car made by the Japanese automaker Honda. It was the result of Project XX, a joint agreement started in November 1981 with the Austin Rover Group of Great Britain and was mechanically related to the Rover 800 series....
(non-US/Canada)
C35B
The C35B (name unconfirmed) is a DOHC V6 with VTECVTEC
VTEC is a valvetrain system developed by Honda to improve the volumetric efficiency of a four-stroke internal combustion engine. The VTEC system uses two camshaft profiles and electronically selects between the profiles. It was invented by Honda R&D engineer Ikuo Kajitani, and was the first system...
which shares basic design properties with its SOHC non-VTEC
VTEC
VTEC is a valvetrain system developed by Honda to improve the volumetric efficiency of a four-stroke internal combustion engine. The VTEC system uses two camshaft profiles and electronically selects between the profiles. It was invented by Honda R&D engineer Ikuo Kajitani, and was the first system...
counterpart but with more aggressive camshafts and slightly lighter cylinder walls. This was the only DOHC VTEC
VTEC
VTEC is a valvetrain system developed by Honda to improve the volumetric efficiency of a four-stroke internal combustion engine. The VTEC system uses two camshaft profiles and electronically selects between the profiles. It was invented by Honda R&D engineer Ikuo Kajitani, and was the first system...
V6 ever built by Honda
Honda
is a Japanese public multinational corporation primarily known as a manufacturer of automobiles and motorcycles.Honda has been the world's largest motorcycle manufacturer since 1959, as well as the world's largest manufacturer of internal combustion engines measured by volume, producing more than...
for longitudinal applications and was only used in one non-production car, the Honda FS-X concept.
Applications:
- 1991 Honda FS-X concept-280 hp (208 kW)