Alfa Romeo V6 engine

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Alfa Romeo V6 engine
20061105 Alfa Romeo 166 3-11 v6.jpg
Alfa Romeo 3.0 V6 24V
Manufacturer Alfa Romeo
Production 1979–2005
Configuration V6 (60°)
Displacement 2.0 L (1,997 cc (122 cu in))
2.5 L (2,492 cc (152 cu in))
2.8 L (2,784 cc (170 cu in))
3.0 SA L (2,934 cc (179 cu in))
3.0 L (2,959 cc (181 cu in))
3.2 L (3,179 cc (194 cu in))
Cylinder block alloy aluminium alloy
Cylinder head alloy aluminium alloy
Valvetrain S/DOHC 60° 2/4-valve
Compression ratio 8.00:1 - 10.50:1
Turbocharger Mitsubishi TD 05H (164)[1]
Garrett T25 (GTV,166)[2][3]
Fuel system 6 Dell'Orto carbs or fuel injection
Management Bosch L-Jetronic
Bosch Motronic
Fuel type Petrol
Oil system wet sump
Cooling system Watercooled
Power output 97–184 kW (132–250 PS)
Specific power 66.1 PS (48.6 kW; 65.2 hp)/L-78.6 PS (57.8 kW; 77.5 hp)/L n/a
105.2 PS (77.4 kW; 103.8 hp)/L turbo
Torque output 178–300 N⋅m (131–221 lb⋅ft)
Dry weight 375 lb (170 kg) Alfa Romeo SOHC V6[4]
Predecessor Alfa Romeo straight-6
Successor JTS engine
2.0L V6 12V Turbo from Alfa Romeo 166.

Alfa Romeo's in-house V6 engine (also known as the Busso V6) design made its initial debut in 1979 in the Alfa 6. Introduced in 2.5 L guise, production engines would eventually range from 2.0 L to 3.2 L displacement. With modifications it is possible to increase engine displacement to 3.8 L (232 cu in). Initially developed in the early 1970s by Ingegnere Giuseppe Busso, the original SOHC 12-valve design employed short push-rods to operate the exhaust valves in a design similar to that of earlier Lancia Fulvia engines. In 1993, the first DOHC version of this engine appeared powering the Alfa Romeo 164. The engine is an aluminium alloy block and head with sodium filled exhaust valves to avoid overheating. The South African market introduced the 3.0 GTV6, predating the international debut of the factory's own 3.0 L engine in 1987. This engine was an Autodelta hand made conversion based on Alfa Sei 2.5 carburated engines enlarged to 93x72mm bore/stroke.

The Alfa Romeo V6 has also been quite popular in kit cars like the Ultima GTR,[5] Hawk HF Series[6] and DAX.[7] and is also used in the Gillet Vertigo sports car.[8] In August 2011 EVO magazine wrote that 'the original Alfa Romeo V6 was the most-glorius sounding six cylinder road engine ever'.[9] and the British Classic & Sports Car magazine noted it as "The best sounding engine, this side of a Maserati V8".

12V, two valve[edit]


A 2.0 L (1,997 cc (121.9 cu in)) version was introduced in 1983. Both carburettor 132 PS (97 kW; 130 hp) and fuel-injected versions were available from the start.


2.0 Turbo[edit]

A 2.0 (1,996 cc ) turbocharged version, derived from the 3.0 L 12v, first with total digital management, was introduced in 1991 in the Alfa Romeo 164 with 210 PS (154 kW; 207 hp). The engine has a 80.0 mm (3.15 in) bore and a 66.2 mm (2.61 in) stroke. This engine is the last on which Busso engineer get his hands on



The 2.5L as longitudinal installation in GTV6.

The original engine displaced 2.5 L (2,492 cc (152.1 cu in)) and produced 158 PS (116 kW; 156 hp). It was a 2-valve-per-cylinder design with a single belt-driven camshaft per cylinder bank and six carburettors fitted. The engine has an 88 mm (3.46 in) bore and a 68.3 mm (2.69 in) stroke.

L-Jetronic Fuel injection system by Bosch was added for the 1983 Alfa Romeo Alfa 6, which produced the same 158 PS (116 kW; 156 hp). The 2-valve engine ended its life in the Alfa 155, where there were two series for this engine, the 2.5 L developing 166 PS (122 kW; 164 hp). Differences between them were small and only on torque and power delivery producing exactly the same horsepower.


2.8 Gleich[edit]

In 1982, the German Alfa Romeo dealer and tuner Gleich offered a 2.8 conversion of the GTV6 2.5 engine. Dieter Gleich was sure that engine displacement enlargement is still the best and, for the life of the engine, the healthiest way of tuning. The engine capacity was increased to nearly 2.8 liters by using new bushings and custom-built forged Mahle pistons while the compression was raised from 9.5 to 10.5:1. The 2.5 liter was rebored to 93 mm (3.7 in). Total displacement was 2,783.7 cc (169.87 cu in)). Power produced were 191 PS (140 kW; 188 hp) at 6300 rpm and torque 24.6kgf-m (178 lb-ft) at 4200rpm.

The magazine "Sport driver" tested a 2.8 Gleich powered GTV6 in June 1982:

"After engaging the first gear and a somewhat careless step on the gas pedal you get a touched feel to the epiphany GTV6 shot, accompanied by the typical Alfa Romeo exhaust sound. It was a pleasure. The fact was the sprint from 0 to 100 km/h is not further under the seven-second limited by a tricky-to-be-shifted five-speed gearbox. The really vehement propulsion waned only when the speedometer 230 km/h mark has left behind. Another eye-opening experience awaits when you realize that the lightning speed to 7000rpm rotating in any gear pinion even in fifth gear still from 1500rpm is completely smooth."


  • 1982 Alfa Romeo Alfetta GTV6 2.8 Gleich

3.0 SA (Autodelta)[edit]

The original 2.5 engine as used in the Alfa Sei was bored and stroked by Autodelta, the former Alfa Romeo racing department to match the racing rules for South African and Australian championships. Bore was increased from 88 mm (3.5 in) to 93 mm (3.7 in) and a new crankshaft stroked to 72 mm (2.8 in). The total displacement was 2,939.5 cc (179.38 cu in) and it's a totally different engine from the later 3.0 (2,959 cc (180.6 cu in)) that powered the 75/Milano models. It was, too, a 2-valve-per-cylinder design with a single belt-driven camshaft per cylinder bank and six carburettors fitted. Special camshafts and carbs were used giving a power figure of 176.4 PS (130 kW; 174 hp) at 5800 rpm. Torque was 222 N⋅m (164 lb⋅ft) at 4300 rpm, while compression ratio was 9:1.

Only 174 complete GTV6 3.0 SA cars were produced in 1984 plus 68 more in 1985. the last ones were fitted with EFI.



Pulled by the racing success of the 3.0 SA engine and looking for more power to boost 75/Milano sales in countries like USA, Alfa Romeo introduced a production version of the 3.0 engine. Bore was 93 mm (3.7 in), as the 3.0 SA, but stroke was increased to 72.6 mm (2.86 in). The total displacement was 2,959 cc (180.6 cu in). As the previous engines, it was a 2-valve-per-cylinder design with a single belt-driven camshaft per cylinder bank. The main difference with the racing 3.0 SA was the use of modern L-Jetronic fuel injection system by Bosch. Power figures vary from 188 PS (138 kW; 185 hp) to 192 PS (141 kW; 189 hp) at 5800 rpm. with compression ratio 9:1.

This engine was modified for transverse placement in the 164 and fitted with a high-performance camshaft and low-restriction exhaust, producing 192 PS (141 kW; 189 hp) in standard form, 184 PS (135 kW; 181 hp) when a catalyzer was fitted in 1991, with the Cloverleaf version producing 200 PS (147 kW; 197 hp).

The same engine was fitted to the SZ and RZ - ES30 Zagato, but even more finely tuned with wilder cams and high compression pistons to a further 210 PS (154 kW; 207 hp).


24V, four valve[edit]

2.5 24V[edit]

2.5L V6 24V from Alfa Romeo 156.

A four-valve version was introduced in 1997 with the Alfa Romeo 156. The engine now produced 190 PS (140 kW; 187 hp). In 2001, the V6 was uprated to 192 PS (141 kW; 189 hp). The 166 used a slightly detuned version to make more low rev torque. This engine version was awarded as the International Engine of the Year in 2000.[11] The engine has a 88 mm (3.5 in) bore and a 68.3 mm (2.69 in) stroke, the same as the two-valve.


3.0 24V[edit]

3.0L V6 24V from Alfa Romeo 164.
3.0L V6 24V, newer version with red texts.
3.0L 24V used in Lancia Kappa had black intake runners.

The engine was upgraded to dual overhead cams and four valves per cylinder in 1993. Due to this and other refinements, this engine produced 211 PS (155 kW; 208 hp) for the regular 1993 164, with 230 PS (169 kW; 227 hp) and 276 N⋅m (204 ft⋅lbf) in the 164 QV with the Euro 3 engine producing 232 PS (171 kW; 229 hp) on the Q4 model which in its final production run in 1996, it got reduced to 228 PS (168 kW; 225 hp) but with increased torque. The final run of 3.0 V6 engines fitted to the GTV and 166 range, produced 220 PS (162 kW; 217 hp). The engine has a 93 mm (3.7 in) bore and 72.6 mm (2.86 in) stroke, the same as the two-valve.


3.2 24V[edit]

3.2L engine from Alfa Romeo 147 GTA.

In 2002 Alfa Romeo introduced the 156 GTA with a 3.2 L (3,179 cc (194.0 cu in)) version of the V6 with 250 PS (184 kW; 247 hp) and 300 N⋅m (220 ft⋅lbf) of torque. Later this engine was also used in the Alfa Romeo 166, GTV, Spider and Alfa Romeo GT in a slightly detuned form 240 PS (177 kW; 237 hp). The engine has a 93 mm (3.7 in) bore and a 78 mm (3.1 in) stroke.[12]


Production end[edit]

The V6 production ended in 2005 at Alfa Romeo Arese Plant;[13] a stock of five thousand were built, to be used in Lancia Thesis, Alfa 166 and Alfa GT models.[14] The engine was replaced in the 159 and Brera by a new 3.2 L V6 unit combining a General Motors-designed engine block with Alfa Romeo cylinder heads and induction. British automotive engineering company Cosworth was keen to buy assembly lines of the Alfa Romeo V6 engine, but the Italian company did not want to sell it.[15] The last version of 3.2 L engine was Euro4 compliant, so it would have been possible to produce it a couple of years more.[16] Engine designer Giuseppe Busso died within three days after the last engine was produced in Arese.

Since 2015, Fiat Powertrain manufactures the all-new, Ferrari-derived 90° V6 Biturbo engine for the Giulia Quadrifoglio.

See also[edit]


  1. ^ "1991 Alfa Romeo 164 V6 Turbo". Retrieved 2009-06-25. 
  2. ^ "1997 Alfa Romeo GTV 2.0 Turbo". www.carfolio. Retrieved 2009-06-25. 
  3. ^ "1998 Alfa Romeo 166 2.0 V6 Turbo". Retrieved 2009-06-25. 
  4. ^ Jan Norbye (1981). "Engine Weight FYI". Complete Handbook of Automotive Power Trains. Retrieved 2007-12-20. 
  5. ^ "Last run wins King of the Mountain". 2006. Retrieved 2012-06-10. 
  6. ^ "Hawk HF2000/HF3000 Series". Retrieved 2009-04-05. 
  7. ^ "DAX Rush Specifications". Archived from the original on 27 February 2009. Retrieved 2009-04-05. 
  8. ^ "Gillett Vertigo Streiff: A body to match its Alfa Romeo heart". Retrieved 2009-04-05. 
  9. ^ EVO Magazine August 2011 page 77
  10. ^ "Rayton Fissore Magnum V6 (1987–1989)". (in French). Retrieved 2010-05-09. 
  11. ^ "Technical Specifications 156". Archived from the original on 10 March 2008. Retrieved 2008-01-28. 
  12. ^ "Alfa Romeo 147 GTA". Retrieved 2008-01-28. 
  13. ^ "News 25.02.2005". Retrieved 2008-01-07. 
  14. ^ "Ad Arese in via di smantellamento la linea di produzione del "6 cilindri"". (in Italian). Retrieved 2009-05-01. 
  15. ^ "LA COSWORTH AD ARESE". (in Italian). Retrieved 2009-05-01. 
  16. ^ "Alfa 147 GTA". Retrieved 2009-05-01. 

Further reading[edit]

  • The Alfa Romeo V6 Engine High-Performance Manual, Jim Kartalamakis, Veloce Publishing, ISBN 978-1-84584-021-1.