The development team at Volkswagen has made major dynamics updates for the Mk8 Golf GTI, with engineering aims including a focus on improving stability, precision and cornering grip for better driving dynamics, while maintaining comfort.
“The Golf GTI has always been synonymous with pure driving dynamics,” explained Karsten Schebsdat, Volkswagen’s head of driving dynamics, steering and control systems. “Few other vehicles in this category offer a similarly finely tuned balance between sportiness and comfort. Thanks to the combination of new running gear setup plus torque-sensing limited-slip differential (VAQ) and Vehicle Dynamics Manager we were able to elevate the outstanding overall performance of the GTI to an even higher level.”
The running gear has received several modifications over the Mk7 setup, designed to increase precision and driving stability. For example, the strut-type front suspension has reconfigured wishbone bearings and revised damping hydraulics, while the springs and buffer stops have been reconfigured to give a front axle spring rate claimed to be 5% higher than that of the Mk7 GTI.
The eighth-generation GTI also features a new aluminium subframe (nearly 7 lbs/3.18kg lighter than that on the Mk7) optimised for maximum rigidity. Modifications to the multilink rear axle include a new wheel mount, wishbone bearing and spring setup, as well as reconfigured auxiliary springs. The spring rate at the rear axle is increased by 15% compared with the Mk7, and the team has also specified new damping bearings and damping hydraulics.
Another major update is the Vehicle Dynamics Manager, a new driving dynamics control system which debuts on the Golf Mk8. The system closely integrates the electronic stability control (ESC) with the electronic differential locks (XDS) and the optional DCC adaptive damping system. Agile and accurate handling is achieved by adapting the individual wheel damping 200 times a second.
The new GTI now comes standard with an electronically controlled, torque-sensing LSD. The development team says that, compared with fully mechanically operated differentials, the electronic system in the GTI offers a variable degree of intervention depending on the actual driving situation and ESC, EDS and XDS+ functions and helps avoid steering corruption.
The VAQ differential in the Mk8 model also includes a multi-plate clutch, which optimises grip and handling in fast corners, helping to decrease understeer in the front-wheel-drive car. Cornering is also aided by the locking torque of the VAQ differential, which can be increased in the two-stage Sport mode: ESC Sport mode increases the ESC thresholds and ASR slip thresholds, while ESC Off mode deactivates ESC altogether.
An optional adaptive chassis control (DCC) system can be specified, which continuously reacts to the road surface and driving situation. For the first time, the DCC running gear’s lateral dynamic components in the new GTI are coordinated and then further optimised by the Vehicle Dynamics Manager. The driver can adjust the Driving Mode Selection settings, influencing the body motion. The damping is calculated for each wheel and adjusted at each of the four dampers within fractions of a second.
In the latest- generation DCC on the Mk8 GTI, the vehicle setup can be extended in Individual mode to go beyond the existing range of the fixed Comfort, Eco and Sport modes. Beyond the Comfort setting, the body is “decoupled” from the road surface as much as possible, thus boosting driving comfort. Beyond Sport mode, there is an extended setting range with maximum damping for minimised body movements and direct and neutral vehicle handling.
An enhanced “progressive” steering setup is standard. VW’s engineers set up the steering ratio more directly than a standard linear steering gear, while applying new software algorithms and a new software application. While conventional steering systems operate on the basis of a fixed gear ratio, the steering in the Mk8 GTI applies a progressive gear ratio, which reduces the amount of lock required to steer when manoeuvering and parking. At higher speed manoeuvres the driver will notice sharper responses thanks to the more direct setup, which also requires less steering wheel input.
The new GTI requires just 2.1 turns lock-to-lock, when fitted with 18in wheels. Progressive steering is differentiated from the basic steering system by variable steering rack and pinion gearing as well as a more powerful electric motor. In contrast to systems with a fixed steering ratio, which compromise between driving dynamics and comfort, the gearing of the steering rack is modified functionally using the steering stroke. The GTI development team says the result is a more agile transition between indirect steering straight-ahead response and direct response to larger turning angles.