Volkswagen Golf GTI under the surface


gti_under_cover_1The first-generation Golf dating from 1974 had been endowed with this uniqueness from its inception. When the number 1 was presented to the press at Munich in May 29 years ago, the original generation already bore the typical features that would immediately make it a bestseller: the dynamic C-pillar resembling the drawn string of a bow, the unequalled variability in the segment at the time, the lively engines and, last but not least, the extremely safe, neutral chassis complete with front-wheel drive were impressive all along the line. The new Golf has all the ingredients to continue in the successful footsteps of its predecessors: a clear plus in terms of dynamics, spaciousness, safety, quality and fascination make it an all-round talent for millions of people from all walks of life.

It is an established fact that the body of the new Golf has increased in size, safety and quality. A major aspect in this respect is the substantial improvement in rigidity. The dynamic rigidity of the body has been increased by 15% in torsion and 35% in flexion; the static torsional rigidity of the body (25,000 Nm/°) has been improved by no less than 80% (!), which is the best value in the segment.

Irrespective of the safety offered, the high level of rigidity does not come at the detriment of the body weight. It has rather been achieved through systematic lightweight construction. Particularly effective lightweight construction measures worth emphasising are the improved join techniques involving laser welding and the optimised layout of the member structure. There has again been a significant increase in the proportion of high-strength body panels used. The net result is a significant plus in terms of body strength, crash safety and comfort whilst optimising weight. For example the laser-welding process: 140 special robots ensure the high body rigidity of the Golf, among other things, by means of laser-welded seams with a total length of 70 metres, as compared to five metres in the predecessor.

gti_under_cover_2The new Golf is essentially characterised by a highly aerodynamic basic body shape. The preconditions for this aerodynamic body shape have been established among other things by defined retreats in the front and rear ends, extremely small shut lines and joint dimensions and the fitting of the windows and headlights flush with the body. In addition, the aerodynamically optimised door mirrors and the trim panels also developed in wind tunnels on the underside of the car make a significant contribution to the drag coefficient of CW = 0.32.

The 2.0 FSI is recommended as the new top-of-the-range engine among the FSI powerplants. This four-valve engine delivers 150 bhp (at 6,000 rpm) and provides remarkably sporty performance. The Golf 2.0 FSI reaches a top speed of 128 mph, accelerates to 60 mph in 8.6 seconds and uses on average just 7.2 litres of fuel–a consumption figure which even a diesel engine would be proud of. The Golf 2.0 FSI comes as standard with a six-speed gearbox. The six-speed automatic gearbox with Tiptronic function is also available as an option to this engine.

gti_under_cover_3To power the generation V Golf GTI, Volkswagen is using a newly developed 2.0 liter FSI turbo engine. The 200 bhp direct injection petrol unit with a high-compression ratio of 10.5:1 makes an ideal GTI engine thanks to its dynamic torque curve (206 lb-ft between 1800 und 5000 rpm). With a standard six-speed gearbox, the four cylinders accelerate the Golf GTI to 62 mph in just 7.2 seconds. The GTI goes from 37 mph to 62 mph in 5th gear in only 7.5 seconds and reaches its maximum at 146 mph. The Euro 4 engine has an average fuel consumption of a frugal 8.0 liters per 100 kilometers. The extremely quick dual clutch gearbox (DSG) for uninterrupted power in gear changes is available as an option. It enables the Golf GTI to charge to 62 mph in 6.9 seconds.

The six-speed manual gearbox features a magnesium selector housing, cable control and very short shifting strokes. A “3-band” synchromesh in the lower gears guarantees maximum shifting comfort. Optimisation of details such as for example reduced-friction smooth-running bearings has helped to further increase gearbox efficiency and further reduce engine fuel consumption. The gearbox has a hydraulic dry single-plate clutch with a vibration-isolating dual-mass flywheel.

gti_under_cover_4The six-speed automatic gearbox (Tiptronic) of the Golf is a real innovation. Up to now Volkswagen has been the only manufacturer in the world to offer a transversally mounted six-speed automatic gearbox at the front in this segment. The shift programs adapt automatically to driving conditions (e.g. driving uphill or towing a trailer). Alternatively, gears can be selected manually by means of a Tiptronic function (+/-). The extremely sporty shift program “S” provides even more agility.

The large effective gearbox spacing results in improved acoustic properties, fuel consumption and acceleration figures in comparison with four- or five-speed automatic gearboxes. The maximum torque capacity of this automatic gearbox is more than 300 Nm. In the interests of easy serviceability, the gearbox is filled with a fluid which does not have to be changed (lifetime fill).

The most innovative gearbox in the world at present is known as DSG or automatic direct shift gearbox. It combines in a fascinating way the comfort of an automatic gearbox with the agility and economy of a manual gearbox. The DSG also has six forward gears. As one of its outstanding design features, the transversally mounted gearbox has two wet clutches (higher thermal load tolerance than dry clutches) with hydraulically regulated pressure. So-called clutch C1 operates the odd gears (plus the reverse) while C2 operates the even gears. This gearbox unit is essentially two gearboxes in one. This substantial level of clutch management is required because there is no longer the typical interruption of tractive force for automatic manual gearboxes when changing gear. An incomparably dynamic and at the same time comfortable gearshift feel is conveyed under conditions of supreme comfort.

gti_under_cover_5In parallel with its fully automatic mode, the DSG has a Tiptronic function, which allows manual gearshifts. Both modes convey a gearshift feel which is characterised by not only absolute comfort but also extreme pleasure when changing gear. Drivers with sporting aspirations experience for the first time that the gears are changed as if by the touch of a button. By recording the wheel speeds via ABS, the gearbox control unit also ensures for example that there are no unwanted upshifts in corners.

Essentially, the engine connected to the DSG always runs in the optimum torque range because every gear generates tractive force immediately. No less crucial is the fact that the new gearbox delivers an extremely high level of agility while maintaining the consumption figures of a manual gearbox. The acceleration and top speed figures are virtually identical.

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