06 Jun 02
The final assembly of the RS 6 takes place at quattro GmbH at Neckarsulm, a wholly-owned subsidiary of Audi AG and Audi's specialist-vehicle builder. Besides building the RS 4 and now the 6, quattro GmbH customises Audis to individual order, fitting its S-Line options packs to various models, boosting power output to request, and producing exclusive accessories and branded items (including a few rather interesting-looking mountain bikes). It takes in partly-assembled basic vehicles from the A6 production line, installs the engine and applies its own unique touches.
And what an engine: the 4.2-litre V8 bi-turbo unit is also produced in-house at Audi, though in this case, by British-based Cosworth Technology, now also a subsidiary of Audi, and makers of the engine for Audi's all-conquering R8 Le Mans contender. Derived from the engine used in the already quite powerful enough S6 (a paltry 340 bhp), it has an aluminium block, a turbocharger and intercooler for each bank of cylinders, five valves per cylinder and a new Bosch Motronic engine management system. Its inlet and exhaust ports have been modified and air ducts redesigned for optimum interaction with the turbos, and an entirely new dual-branch exhaust system fitted. Further mods include the moving of the battery to the rear and positioning the air cleaner (with its carbon-fibre composite housing) over the engine, all in aid of improved weight distribution.
To handle the engine's power and torque, the RS 6's transmission is a five-speed tiptronic set-up derived from that of the 6.0 V12 Audi A8, but modified for quicker gear changes and shorter gaps between ratios. Sport mode re-sets the 'box to change up later and down sooner, and the gearbox can also be "manually" controlled via either the selector lever or steering wheel-mounted paddles. And when you have 450 bhp to play with, stopping power is pretty important too: race-developed composite brake discs do the business, with a 'floating' cast friction ring attached to an aluminium brake-disc chamber via 14 pins. This is said to improve braking stability, especially at high operating temperatures and under extreme conditions. The brake discs are 365 mm wide up front and 335mm wide behind, with massive eight-piston callipers on the front pair. The ABS and EBD control systems have been re-mapped accordingly, and work in conjunction with a whole armoury of electronic control systems: EDL (electronic differential lock with active braking control), ASR (Anti-Slip Regulation), MSR (engine drag torque control) and yaw-control, plus a new electronic system called Dynamic Ride Control (DRC). This is a special damping system that controls rolling or pitching by balancing the shock absorbers at each diagonally-opposite corner, for high stability when cornering and more precise steering responses. The suspension has been substantially revised, with modified axle geometry and altered axle weights; the springs and shock absorbers have also been retuned.
