The Golf GTI is offered with a standard sport suspension that is tuned to the higher power of the Volkswagen car. Therefore, the body was lowered 15 mm compared to the less powerful Golf models. In front, a MacPherson suspension provides for precise tracking; at the rear, there is the modular performance suspension. Equipped as standard with the further advanced XDS+ vehicle dynamic function and the new progressive steering system (significantly smaller steering angle input required from one end stop to the other: just over two full turns), the Golf GTI is advancing more than ever into the realm of high-class and significantly more expensive sports cars with its agile and safe handling properties.
Golf GTI Performance
The Golf GTI Performance, whose power was boosted to 230 PS, makes an especially impressive appearance with its front differential lock that was exclusively developed for this version. In this Volkswagen, the advantages of the GTI-specific sport suspension, new progressive steering system, further advanced XDS+ vehicle dynamic function and electronic front differential lock all add up to handling that is far superior to that of the majority of competitors. The Golf GTI Performance is also equipped with internally-ventilated disc brakes at all four wheels. The brake system uses 340 x 30 mm discs at the front and 310 x 22 mm at the rear wheels. The 220-PS GTI has internally-ventilated discs at the front wheels and unventilated discs at the rear (front: 314 x 30 mm; rear: 300 x 12 mm).
Vehicle dynamics
The running gear layout of the new Golf GTI has been tuned for maximum driving fun combined with a high level of vehicle stability. Drivers will notice that steering response is now even more agile than in the previous model thanks to more direct steering gear ratios. Maximum attainable speeds through bends were also increased, because of more neutral running gear tuning and optimisations of the XDS+ system. In the Golf GTI Performance, the transverse acceleration potential was further increased by the front differential lock; this is especially true of the car's acceleration out of bends. Applicable to both versions of the new Golf GTI, is that their neutral handling in bends goes hand in hand with very good vehicle stability right up to the maximum speed range, thanks to an innovative and careful layout of all running gear components. This exceptionally high vehicle stability is especially noticeable during lane changes and during engine load changes. The development team also made a special effort to tune the new Golf GTI for harmonious and predictable reactions of the running gear. The results: drivers will be able to quickly and intuitively master handling of the GTI after a very short time.
In parallel to improvements to vehicle dynamics, the suspension comfort was also enhanced relative to the previous model. For example, the acceleration forces acting on passengers when driving over small and large road bumps have been noticeably reduced. The comfort levels realised in the new Golf GTI show that sporty handling does not necessarily involve unpleasant ride harshness. The described broad array of positive handling properties – direct, neutral and stable handling up to performance limits combined with a high level of ride comfort – make the driving properties of the seventh generation Golf GTI unique in the competitive field.
XDS+
The XDS system that was first introduced in the Golf VI was further developed into the advanced XDS+ system for the new Golf GTI. Technically, the XDS+ electronic differential lock is a functionality that is integrated in the electronic stabilisation programme (ESC) for improved vehicle dynamics. XDS+ is an extension of XDS, which is familiar from the previous model; its functionality has now been extended to cover all unbraked driving states. The new system improves agility and reduces the need for steering angle inputs by targeted brake interventions at the wheels on the inside of the bend of both axles. In addition, XDS+ is effective over all conceivable road friction values; it results in more precise handling, even on snow. The well-known benefits of XDS – such as significantly reduced understeer and improved traction – were also perfected.
Front differential lock
A newly engineered electronic front differential lock is being used exclusively in the Golf GTI Performance. To date, Volkswagen is the only carmaker to utilise an electronically controlled differential lock in a front-wheel drive production model. Compared to purely mechanical locks, the front differential lock integrated in the Golf GTI Performance offers advantages such as a variable degree of locking and comprehensive interfaces to the ESC, EDS and XDS+ functions. This makes it possible to completely avoid negative effects on steering response and steering precision that otherwise occur with mechanical locks. As a result, the system realises the full potential and maximum performance of a differential lock with regard to vehicle dynamics, because comfort is not impaired under any circumstances.
Functionality of the front differential lock. The front differential lock operates without any power losses here, so that the power produced by the engine is transferred 100 per cent to the road and is fully available to propel the GTI.
The electronic front differential lock utilises a multi-plate unit located between the right side driveshaft and the differential case. The hydraulic pressure needed to actuate the plates is generated by an electric motor driven piston pump. The locking moment that is generated here is proportional to the hydraulic pressure. The hydraulic pressure is controlled by the pump speed that is prescribed by a control module. This control module takes numerous parameter inputs – such as wheel speed, vehicle speed, yaw rate and transverse acceleration – and computes the ideal locking moment.
1,600 Nm maximum locking moment. If the control module detects wheel slip at one of the front wheels, the plates are actuated to redistribute the drive torque from the wheel with the lower grip level to the wheel with the higher level. The maximum locking moment is 1,600 Nm, so that if necessary all of the drive torque can be directed to just one front wheel; that corresponds to a locking value of 100 per cent. This produces maximum traction for a front-wheel drive vehicle, even under difficult roadway conditions and in turning situations.
Torque vectoring effect. When accelerating out of a bend, the drive torque is increased at the wheel on the outside of the bend. This produces an asymmetrical drive torque distribution that matches the dynamic wheel load distribution. This is known as a "torque vectoring effect" which reduces acceleration-related understeer. As a result, the Golf GTI Performance handles neutrally and precisely tracks along the ideal line. The existing grip level is optimally exploited. This lets the driver apply much greater force to the accelerator pedal at the apex of a bend, which in turn results in significantly higher speed exit speeds of the Golf GTI Performance out of bends.
ESC intervenes more gently and with delay. In highly dynamic situations, such as in fast driving through alternating curves, unexpected avoidance manoeuvres or load changes, the front differential lock is used to dampen yaw movements. When oversteer occurs, the front differential lock generates a stabilising yaw moment; this means that ESC interventions can be made gentler and later or might even be avoided altogether. So, the controlled front differential lock stands for even more driving fun and better performance.
ESC Sport
In the new Golf GTI, Volkswagen is offering the "ESC Sport" function for very experienced drivers. The system is activated by a two-stage switch on the centre console. If the driver pushes the button once briefly, it deactivates the ASR function (traction control). When the button is pressed longer than three seconds, Electronic Stability Control (ESC) switches to the "ESC Sport" mode. In very fast driving with lots of bends – such as on a race course – the ESC system reacts with a delay, which enables even greater agile handling properties. As an alternative to activation by the pushbutton on the centre console, ESC can now also be activated or deactivated by settings in the CAR menu.
Progressive steering
The progressive steering system is celebrating its debut in the new Golf GTI. It is a standard feature for both power levels. This steering system lets drivers make a turn of a given radius with smaller steering wheel movements. That is, the driver does not need to reach over the steering wheel as often in tight bends. With progressive steering, it takes 2.1 turns of the wheel (380°) to reach the end stop; in the standard steering system of the less powerful Golf models it takes 2.75 turns (500°). Background: Conventional steering systems operate with a constant gear ratio. The new steering of the Golf GTI, meanwhile, operates with a progressive steering gear ratio. This reduces steering work perceptibly when manoeuvring and parking. On country roads with lots of bends, and when making turns, the driver experiences a plus in dynamics due to the more direct layout.
Technically, progressive steering differs from the basic steering system primarily by the rack's variable tooth spacing and a more powerful electric motor. Its functional difference: Unlike with constant steering ratios, which by necessity always represent a compromise between dynamic performance and comfort, here the steering rack's toothing is significantly modified by the steering stroke. This results in more precise and relaxed driving in the middle steering range up to high speeds; due to the smaller steering input angles that are required, the system offers significantly greater agility and more driving fun on roads with lots of bends. At lower speeds, on the other hand, such as in city driving or parking situations, the Golf GTI is much easier to handle thanks to the lower steering input angles – offering a perceptible gain in comfort.
DCC dynamic chassis control
A second generation DCC dynamic chassis control system is at work in the Golf GTI. DCC offers the three driving modes "Comfort", "Normal" and "Sport", which are now selected and displayed under "Driving profile selector" on the touchscreen of the centre console. Besides offering a "Normal" mode, the DCC system, which was specially tuned for the GTI, now offers the "Comfort" mode, which is indeed comfort-oriented but still reflects typical GTI properties. In "Sport" mode, especially dynamic and agile handling is implemented. In the "Individual" driving profile, the DCC mode can even be configured with any other desired driving profile properties.
The DCC system adaptively regulates the damper valves via a further developed and refined Volkswagen control algorithm which sets the damper characteristic. In doing so, DCC evaluates input signals from wheel displacement sensors and accelerometers as well as vehicle bus information from the Chassis-CAN bus. It then computes the optimal damper force for every driving situation and adaptively adjusts this force. Damping forces are selectively applied to the four wheels individually.
In the new DCC generation, it is now also possible to fully independently vary rebound and compression damping for transverse dynamic manoeuvres – a significant benefit in optimising vehicle dynamics. The damper valves were also modified for further improved response.
MacPherson-type front suspension
A MacPherson front suspension (spring struts) with a newly developed low wishbone and track-stabilising scrub radius enables optimal handling and steering in the GTI as well as a balanced response to vibration. All components were reworked for improved functionality, weight and cost. This resulted in a weight savings of 1.6 kg compared to the previous model. This was made possible, for example, by the use of high-strength steel in the transverse links and an innovative bionic approach to designing the pivot bearings. The subframe is centrally positioned on the front axle; its frame - designed for maximum transverse rigidity - handles loads from the engine mounts and steering as well as loads of the front suspension components.
The now fully tubular anti-roll bar has a spring rate that was specifically tuned for the handling of the new GTI. The rubber bearings are vulcanised directly onto the painted anti-roll tube; this assures optimal acoustic properties and optimises the responsiveness of the anti-roll bar which is important to vehicle dynamics. A new aluminium pivot bearing was also designed for the GTI. The use of aluminium and the bionic design of this pivot bearing enabled a weight reduction of 2.8 kg. Compared to the previous model, the location of the centre of motion was moderately raised for quicker and more precise response of the new GTI front suspension.
Modular performance rear suspension
The rear suspension of the Golf GTI was further developed from the perspectives of improved kinematics, acoustics, weight situation and modularity. However, nothing has changed with regard to its fundamental approach of consistently separating longitudinal and transverse rigidities. The low longitudinal rigidity has been preserved by the soft axle control of the trailing link; this was a necessary precondition for further improving ride comfort.
Furthermore, Volkswagen successfully improved the transverse rigidity of the modular performance suspension, which is important for steering behaviour, by a new tie rod bearing tuning. Tracking and camber values are individually tuned by eccentric screws on the spring link and at the upper transverse link according to requirement for each vehicle type. Key design changes to the rear suspension are the connections of the tubular anti-roll bar and the suspension damper, which are now made at the spring link. This reduces forces within the suspension; there are also significant package advantages. In addition, the suspension was made 4.0 kg lighter in weight by structural optimisations of many components and the use of high-strength steels.
Note:
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Features and technical data apply to models offered in Germany. They may differ in other countries.