VR6 engine

The VR6 engine is a configuration developed by the Volkswagen Group. It is similar to the V engine, but with the cylinders offset from each other and tilted by 10.6° or 15° instead of the more common 45°, 60°, or 90°.


Description

The name VR6 comes from a combination of V engine (German: V-Motor) and the German word Reihenmotor (straight engine). The combination of the two can be roughly translated as "inline V6 engine".

The VR6 was specifically designed for transverse installation in front wheel drive vehicles. By using the narrow 15° VR6 engine, it was possible to install a six-cylinder engine in existing Volkswagen models. A wider V6 engine of conventional design would have required lengthening existing vehicles to provide enough crumple zone between the front of the vehicle and the engine, and between the engine and the passenger cell. In addition, the VR6 is able to use the firing interval of an Inline-6 engine. As a result, it is nearly as smooth as an Inline-6.

The narrow angle between cylinder banks also allows just two camshafts to drive all of the valves, and a single cylinder head to be used. This simplifies engine construction and reduces costs. In early (12 valve) VR6 engines, one camshaft is used per bank of cylinders. This is most similar to the operation of a SOHC V6 engine. However, later (24 valve) VR6 engines use one camshaft for all intake valves and one camshaft for all exhaust valves. This is most similar to a DOHC Inline-6 engine.

There are several different variants of the VR6 engine. The original VR6 engine displaced 2.8 L and featured a 12 valve design. These engines produced 174 PS (172 hp/128 kW) and 240 N•m (177 ft•lbf) of torque.


History

The VR6 engine was introduced in Europe in 1991 in the Passat and Corrado, and in North America the following year. The Passat, Passat Variant wagon and US-spec Corrado used the original 2.8 L design, while the Euro-spec Corrado and the 4WD Passat Syncro received a 2.9 L version with 190 PS (187 hp/140 kW). This version also had a free flowing 6 cm (2.5 in) catalytic converter, enlarged inlet manifold and larger throttle body.

The 2.9L engine, as destined for the Corrado, was originally designed to benefit from a dual tract variable-length inlet manifold called the VSR (German: "Variables SaugrohR") and made by Pieronberg for VW Motorsport. This gave extra low-down torque but was deleted before production on cost grounds and was instead offered as an aftermarket option. The design was later sold to Schrick who redesigned it and offered it as the Schrick VGI ("Variable Geometry Intake").

In 1992, with the introduction of the Golf's third generation, a six-cylinder engine was available for the first time in a lower-midsize segment hatchback in Europe. North America only received this engine in 1992 with the CorradoSLC ,1994 in the Jetta, and in 1995 in the Golf GTI... at the same time the European model started to use the 2.9 L in the VR6 Syncro model. The corresponding Vento/Jetta VR6 versions appeared in the same years.

In 1997, VW removed a cylinder from the VR6, creating the VR5, the first block to use an uneven number of cylinders in a V design (other than the Honda V3 triples of MotoGP fame). This version, which had a 2.3 L capacity, was capable of 150 PS (148 hp/110 kW) and had a maximum torque of 209 N•m (154 ft•lbf). It was introduced in the Passat in 1997, and later in the Golf and Bora in 1999.

For 1999, VW added further modifications to the design, with the introduction of the 24-valve 2.8 L VR6. This engine produced 204 PS (201 hp/150 kW) and 265 N•m (195 ft•lbf) of torque. The new version was not available in the Passat (as it was incompatible with the then-current generation's longitudinal layout), but was introduced as the range topper in the Golf and Bora. The VR6 name was dropped as a commercial designation, and the 4WD system (4Motion) was now standard on the V6 in Europe. The corresponding multivalve V5 was only released in 2001, with a 20 PS power increase, to 170 PS (168 hp/125 kW). The multivalve V6 was only introduced in North America in 2002 (where it retained the VR6 name).

In 2003, a high performance 3.2 L version of the engine was introduced to power VW's limited-production Golf R32 and a new range-topping variant of the Audi TT. According to Volkswagen, this variant produced 250 PS (247 hp/184 kW) and 320 N•m (236 ft•lbf) of torque in TT trim and 241 PS(238 hp/177 kW) in R32 trim. In 2004, VW imported the Golf R32 to North America using the same 3.2L VR6 as the Audi TT. Although it was rated by VW at 241 HP, the North American R32 featured a larger Mass Airflow Sensor than the European R32 (3" in diameter compared to 2.75"), and the airbox differed as well.

The 3.2 is now used as a range-topper in Audi A3 or as an entry level version in the VW Touareg and Porsche Cayenne, although the version used in the Cayenne features modifications to the head as well as the intake and timing systems.

In 2005, the European market version of Volkswagen's fifth generation Passat went on sale with a revised version of the 3.2 L VR6 as its top-spec motor. For North America, the Passat received a new 3.6 L VR6 with a narrower 10.6 degree cylinder angle, producing 280 PS (276 hp/206 kW). Both the 3.2 and 3.6 feature Fuel Stratified Injection. The introduction of the Passat VR6 also marked the first time a VR6 powered vehicle was made available in North America before Europe. The 3.2 VR6 is also being used to power a new MKV platform R32 in both Europe and North America. Contrary to earlier rumors, there will not be a 3.6 VR6 coming in a MkV golf to North America; the MkV R32 for North America will remain a 3.2 VR6, and will only be available with a Direct-Shift Gearbox.


Usage

The VR6 was used by Volkswagen in:

* VW Golf Mk.III and Mk.IV
* Golf R32 MK.IV and Mk.V
* VW Passat (B3, B4, and B6 chassis)
* VW Vento/VW Jetta Mk.III
* VW Bora/VW Jetta Mk.IV
* VW Corrado
* VW Phaeton
* VW Touareg
* VW Transporter T4 and T5
* VW Sharan/SEAT Alhambra/Ford Galaxy

The VR6 is also used in other Volkswagen Group products, namely:

* Audi A3 Mk.II
* Audi TT
* SEAT León Cupra

The Porsche Cayenne, which shares its chassis with the VW Touareg, also uses the 3.2 L VR6 as its base engine.


Other applications of VR6 technology

Volkswagen has also developed a series of engines which use narrow angle designs mated together at 72 degrees. For example, two VR6 engines mated together at 72 degrees result in a W12 configuration, which is significantly shorter than a V12 engine, but only marginally wider. W8 and W16 designs were developed in a similar fashion. The W8 uses two four-cylinder VR engines mated together, and the W16 uses two eight-cylinder VR banks.