Volkswagen W8 Passat
Friday 25 July, 2003
The name Volkswagen is German for "car for the people", a car for everyone - ironically, the Volkswagen group is now Europe's largest manufacturer of automobiles and is moving the brand upwards and away from its proletarian roots.
After years operating at the lower end of the market, Volkswagen AG, now owns such prestigious marques as Audi, Bentley, Bugatti, and Lamborghini and one of the key strategies of the group has been the development of a range of large-displacement engines to do justice to its newly acquired premium brands.
This new family of engines uses a W configuration and comes in 8, 10, 12 and 16 cylinder versions. The bigger capacity W engines will provide the power for some high-end automobiles such as the Phaeton prestige sedan aimed at BMW's 7 series and Mercedes S class, while a 750 kW, twin-turbo W16 will power the world's fastest production car, the Bugatti Veyron sports car (story 1290 at Gizmo.com.au).
The biggest advantage of the W configuration used by Volkswagen is the compact size and weight of the engines - by using two narrow-angle V-configuration engines spliced together, the motors are much shorter than V configuration engines with the same number of cylinders.
The first example of this new W-configuration engine range to reach Australia is the 4.0-litre, 32-valve, 202kW, W8 powerplant, in the range-topping Passat. The smallest and lightest eight cylinder automobile engine in volume production, its cylinder head consists of two V4 modules with cylinders set at 15 degrees to each other and the basic W-shaped layout is the product of the double V with a cylinder bank angle of 72 degrees.
The engine is installed longitudinally, just ahead of the front axle and drives all four wheels via Volkswagen's 4MOTION all-wheel-drive system and a five-speed electronic automatic transmission with Tiptronic.
Now the resultant car is quite spectacular; the motor is smooth and torquey and drives like a limousine at modest speed, with great power available once the revs rise.
If there's a problem, it will be Volkswagen's chances of finding enough people prepared to pay $100,000 ($97,900 plus on road costs) for a car which looks very much like a V6 Passat.
There are some distinguishing features but they aren't obvious at a distance and as good as the car is, we suspect that the W8 Passat isn't going to be making much of a dent in the sales figures of BMW or Mercedes because it's, well, - a Passat.
Externally, W8 Passats are distinguished by subtle badging, a bootlid spoiler, bi-xenon headlights, sporty 17-inch wheels and slightly reduced ride height resulting from the sports suspension.
VW didn't go to the trouble of buying Bentley and Lamborghini and resurrecting Bugatti because it doesn't recognize the value of a prestige badge, so we suspect that the aim of the W8 Passat exercise is to showcase the motor and nudge the brand up the scale a notch into the prestige sedan segment. If that is the aim, then it has been achieved, as the Passat is a great vehicle with plentiful power all the way to the electronically governed top speed of 250km/h.
Around town, the W8 Passat drives beautifully with peak torque of 370 Nm available at 2750 rpm but spin the engine beyond 4000 rpm and the W8's performance moves into sports car class.
Complimenting this increased power and performance, W8 Passats feature unique reinforced bodyshells providing higher torsional rigidity than other Passat models.
Weighing just 190 kg and measuring only 420mm in length, 710mm in width and a mere 683mm in height, Volkswagen's W8 is two 15 degree V4 engines fused together with staggered cylinder bores and offset at an angle of 72 degrees. However because the 15 degree angle is so narrow, a weight saving has been delivered by using a single cylinder head cover for all four cylinders in each V4.
Inside, there are actually seven shafts revolving. Four are the overhead camshafts, manufactured by interior high-pressure reshaping. Another is the five-bearing crankshaft. The remaining two act as balancer shafts (Lancaster principle) designed to eliminate undesirable second-stage vibrations normally inherent with traditional V engines.
The crankshaft is made of tempered steel and has journals offset by 180 degrees. In order to get identical ignition timing with a V-angle of 72 degrees, the crank journals are offset by 180 degrees to each other. The result is a 'flat' crankshaft and a firing order straight from Formula One Grand Prix engines of 1-5-2-6-4-8-3-7. This underlines the positioning of this engine for Volkswagen: for all its refined features, it is an engine designed to generate impressive supercar power and torque.
Similarly with the W8's four variable camshafts that are driven by simplex chains from the intermediate shaft. The inlet camshafts can be adjusted continuously over 52 degrees and the exhaust camshafts in two stages by 22 degrees.
With the use of special non-return valves in the oilways, the camshaft adjustments can be carried out at very low oil pressure. The oil supply for the control unit comes direct from the engine oil circulation via electronically-controlled four-way valves - hence whether in high gears on the highway or in low gears driving around the city, the engine always provides instantaneous thrust.
As well as Volkswagen's 4MOTION all-wheel-drive system with centre Torsen differential and four electronic diff locks, the Passat W8 also features ESP, Volkswagen's electronic stabilisation program and traction control.
Under full-load acceleration or on a slippery surface, the Torsen centre differential automatically corrects the drive power distribution in favour of the wheels with the most grip. At the same time, the electronic differential lock (EDL) ensures, with the intermittent application of the brakes, that even at speeds under 80 km/h, the wheels are prevented from spinning.
Under normal driving conditions, the W8 Passat's power is distributed 50:50 to the front and rear wheels. Compared to a traditional rear-drive vehicle, this means the power transmitted to each wheel is halved - meaning a reduction in the lateral forces of the wheels and thus safer handling
W8 Passat's active safety systems also include Volkswagen electronic stability program (ESP) and the traction control system (TCS) - both as standard features. These systems operate using corrections to driving characteristics, not only via the brakes but also via the engine management system.
Brake Assist with electronic brake pressure distribution (EBD) is also standard. This system recognises via sensors that the driver is demanding faster and heavier braking than normal - but because full-pressure braking is frequently initiated by less experienced motorists with too little pressure, brake assist increases the braking pressure and thus retardation up to its maximum. Of course with the anti-lock system and EBD, the wheels are prevented from locking thus steering control is maintained at all times.
Just as impressive as the 4MOTION and electronic systems is Volkswagen's suspension dynamics. At the front, the W8 Passat features a four-link axle with spring/damper units, while the rear sees a torsion beam trailing arm axle with coil springs.
The fully galvanized W8 Passat bodyshell has increased torsional rigidity compared to other Passat models. Specifically, W8 models receive pinpointed reinforcements of the side sills, the B-pillars and the centre roof member that connects them, the centre tunnel member, the side collision protection elements in the doors, the upper side members and the inner guards.
The torsional stiffness of the W8 Passat is in the top range (24,000 Nm per degree) and the inherent torsional frequency is also the very top level at 49 Hertz.
In Australia the W8 Passat is only available with the highest available airbag package that includes driver and passenger front airbags plus side curtain airbags. The airbags themselves are supplemented by an active seatbelt system with front and rear belt tensioners.
Also featured is an intelligent CAN-databus controlled on-board management system that, after an accident, automatically releases the central locking system and turns-off the fuel pump.
The dash-mounted Blaupunkt Satellite Navigation screen, Climatronic automatic air-conditioning system and CD sound system are integrated in the console.
W8 Passat also comes standard with Volkswagen's 'Park Distance Control' system that warns the driver with a series of audible beeps when reversing to advise the proximity of other cars, poles, trees, buildings etc.
The solar-powered sunroof uses the sun's rays to power a ventilation system that maintains fresh air circulation to the cabin - even while the car is parked and the engine is turned off.
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