Alfa Romeo V6 Busso engine, a 26-year history

After the 2600’s retirement from the market in 1969, Alfa Romeo decided to focus its energy on relaunching itself in the world of larger sedans. Thus was born the project 119 which led to the launch, in 1979, of the Alfa 6. However, the larger dimensions than the previous model required the use of a 6-cylinder engine, therefore Alfa decided to develop a new V-architecture engine.

Designed by Giuseppe Busso, from which the whole family of these engines takes its name, the Alfa Romeo 60 ° V6 it was produced from 1979 to 2005 in different versions and widespread on models such as the Alfa 90 Quadrifoglio Oro, the Alfetta GTV6 2.5, the 75 3.0 V6 and the more recent 147 GTA, 156 GTA and Spider 3.2 V6 24 valves.

The first 2.5-liter V6 Busso

The first version of the V6 “Knock”, as we have said, made its debut on the Alfa 6. Born to replace the 2.6-liter in-line 6 cylinders, plagued by torsional problems of the crankshaft that hindered the increase in power, the 6-cylinder V of 60 ° had 88 mm bore and 68.3 mm stroke for a displacement of 2,492 cc and developed an initial power of 158 hp.

Made of aluminum, the 2.5-liter V6 “Busso” had a single distribution overhead camshaft per bank driven by a rear belt that directly controlled the intake valves while each of the exhaust valves were moved by means of a small tappet and a cup. In 1987 the 3-liter appeared on the Alfa 75, again with 12 valves with a power of 192 HP.

The turbo version of 1991

Already at the beginning of the 1980s, engineer Busso was considering the hypothesis of creating one supercharged variant of its jewel to increase its performance even more without risking the tax burdens that affected the larger displacements in those years and that had even convinced Ferrari to propose a V8 of only 2 liters but supercharged for the 208 Turbo. The idea was realized in 1991 with the new unit mounted on the 164 V6 Turbo.

This engine, derived from the 3-liter V6 and supercharged first by a Mitsubishi / Piaggio turbine and since 1992 by a Garrett T25, was characterized by a volume reduced to 1,996 cc. Its main peculiarity, in addition to the aluminum alloy construction, was however the complete electronic management: from the accelerator to the detonation control for each cylinder.

Awarded as the best engine in its category in 1991, the V6 “Busso” Turbo was able to withstand very high specific powers and over the years it has been used on several sports cars of the Alfa Romeo company such as the GTV V6 TB and Spider V6 TB and the 166 Super V6 TB. Produced until 2000, the 2.0 V6 Turbo is still considered the last engine ever made completely from Alfa Romeo without the intervention of Fiat.

The 24 valve versions

In 1992, starting from the architecture of the 12-valve V6, a new version of the 3-liter 24-valve was introduced which used numerous specially designed elements such as the pistons, the aluminum cylinder heads, the distribution shafts with their control system and the spark plugs with single coils.


To these new components was added one reduction of valve angle from 46 ° to 37 ° 10 ‘, which allowed greater compactness and efficiency. In this case, the distribution was entrusted to 4 camshafts controlled by a toothed belt. Subsequently, a 24-valve variant of the 2.5-liter V6 was also made, with a power of 190 hp, which entered the range of 156 and 166.

Finally, in 2002 came the 3.2-liter variant that became famous for pushing the renowned 156 GTA and 147 GTA and the top versions of the GT, Spider and GTV.

Engine Production period Power Models
2.5 V6 12v 1978-1996 da 158 a 165 CV Alfa 6, Alfa 90 QO, Alfetta GTV6 2.5, 155 V6, Alfa 75 QV
2.0 V6 12v 1983-2001 da 132 a 210 CV 164 V6 Turbo, 164 Super V6 TB, 166 Super 2.0 V6 TB, Gtv 916 V6 TB
3.0 V6 12v 1987-1999 da 175 a 207 CV Alfa 75, 164, 164 Q.V.’90, Spider (916), Lancia Thema, S.Z., R.Z.
2.5 V6 24v 1997-2004 da 188 a 190 CV 156 V6 24v, 166 2.5 V6
3.0 V6 24v 1992-2003 da 210 a 232 CV 64, 164 Q.V.’93, 164 Q4, GTV (916), Spider (916), 166
3.2 V6 24v 2002-2006 da 230 a 250 CV 147 GTA, 156 GTA, GT, 166, GTV (916), Spider (916)

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