Audi RS 4

Audi RS 4

After a long hiatus, the second Audi RS4 quattro (Typ 8E), built on Audi's "B7" A4 platform, by quattro GmbH in Neckarsulm, Germany (a wholly owned private subsidiary of Audi AG), was unveiled in February 2005 at Audi's 'quattro Night' celebration at the company headquarters in Ingolstadt, Germany. The RS4 came down a replica of a ski jump then spun several times on an ice rink before coming to rest in the center of the ice. After several minutes to allow the assembled media and guests to examine the car, the RS4 climbed the ski jump and parked near the top. The ski jump was an homage to an audi commercial from 1986 where an Audi climbed a ski jump in Finland to showcase its superior traction due to the quattro drivetrain. The RS4 became available to European customers in mid 2006. It was introduced at the 2006 North American International Auto Show in January, and arrived in June 2006 North America. There was no RS4 built on the Audi "B6" platform which served as the basis for the Audi A4 between 2001 and 2005.

The B7 RS4 is an almost complete departure from previous RS cars, as it was initially available as a saloon/sedan; with an Avant (estate/wagon), and Cabriolet (convertible) versions arriving later. Only the RS6 had taken this similar route (saloon and Avant) before; the previous RS4 and RS2 were available exclusively as Avants. The production run of the B7 RS4 was 2006 to 2008 inclusive, although only 2007 and 2008 model year were sold in the USA.

The B7 RS4 Cabriolet, available in Europe from late 2006, was made available as a model year 2008 vehicle in the USA.

Audi factory numbers indicate that the B7 RS4 saloon can accelerate from 0-100 km/h (62 mph) in 4.8 seconds, and arrive at 200 km/h (125 mph) in 16.6 seconds. Many independent tests have shown that the stock B7 RS4 can readily achieve 0-60 mph times around 4.0 seconds. This is consistent with the pattern of conservatism that is usually found in Audi's official performance numbers. To date, approximately 10,000 B7 RS4s have been built of which around 1,700 are in the USA.

In the saloon, luggage space is 460 L (16.2 cu ft) with the rear seats in the upright position, and 833 L (29.4 cu ft) with the seats folded flat. Kerb (curb) weight of the saloon variant starts at 1,680 kg (3,704 lb) (dependent on specification). This results in a power-to-weight ratio of just 3.93 kilos per bhp.
Powertrain

Power comes from a 4163 cc, V8 32-valve Fuel Stratified Injection (FSI) petrol engine (code BNS). This is a highly reworked high-revving variant from the existing 4.2 L V8, having cylinder-direct fuel injection, and 4 valves per cylinder, instead of 5. It has two chain-driven double overhead camshafts (DOHC) per cylinder bank. It produces a total output of 420 PS (309 kW/414 bhp), over 100 PS (99 hp/74 kW) per litre. The engine also produces 430 N·m (317 ft·lbf) of torque, 90 percent of the total torque being available between 2,250 and 7,600 rpm. The engine breathes through four hi-flow sports catalytic converters, and exits via twin oval tail pipes with integral dynamic silencer/muffler valves. Engine management is controlled via a Bosch Motronic MED 9.1 engine control unit, utilising "Bosch E-Gas", a drive by wire throttle. Ignition uses eight individual spark coils, utilising mapped direct ignition, with triple-electrode spark plugs. Ignition timing is monitored with the aid of four knock sensors.

A six-speed Getrag manual gearbox (code JHM) is the only transmission available (gear ratios - 1st: 3.667, 2nd: 2.211, 3rd: 1.520, 4th: 1.133, 5th: 0.919, 6th: 0.778).

Another focus of the B7 RS4 was on the quattro permanent four-wheel drive, with the 'third generation' asymmetric/dynamic Torsen T-3 centre differential, featuring a 40:60 front-to-rear torque split under normal conditions. Audi stressed that this would result in a more neutral response in corners, and a more dynamic driving experience. Also more aggressive Torque Bias Ratio (TBR) was used and set to 4:1, as opposed to 2:1 on standard A4.[citation needed] That means that one side of the differential can handle up to 80% while the other side would have to only handle 20% of applied torque.

Front and rear axle differentials are conventional "open" types, 233with "Electronic Differential Lock" (EDL), with a final drive ratio of 4.111.

Suspension & Steering

The B7 RS4 also incorporates Audi's "Dynamic Ride Control" (DRC) sports suspension mechanism, where a fluid mechanical linkage between diagonally opposing front and rear suspension dampers is used to counteract vehicle pitch and roll.

Speed sensitive "servotronic" variable electro-hydraulic power assisted steering is controlled from a compact flat-bottomed steering wheel, finished in perforated leather with mock-aluminium trim.

Brakes, Wheels & Tyres

Standard brakes on the RS4 consist of cross-drilled, radially ventilated and floating 365 mm (14.37 in) cast iron front brake discs, with Brembo eight-piston calipers. These, along with the transmission, are supplied with a cooling airflow from NACA ducts mounted in the front undertray. A lighter "Audi Ceramic" drilled, vented and floating 380 mm (14.96 in) x 38 mm (1.496 in) Carbon fibre-reinforced Silicon Carbide (C/SiC) composite front SGL Carbon discs, with Brembo six-piston monobloc aluminium calipers were an option from 2007 model year onwards (and only with 19 inch wheels). These reduce unsprung weight, and improve steering response and handling as a result. Rear brakes are drilled, vented and floating 320 mm (12.60 in) x 22 mm (0.866 in) iron discs, with single piston floating caliper.

Standard wheels are 19 inch alloy wheels (9Jx19" ET29 "7-arm double spoke") with 255/35 ZR19 96Y ExtraLoad (XL) high performance tyres. A no-cost option of 18 inch alloy wheels (8½Jx18" "5-spoke design") with 255/40 ZR18 Y XL tyres was also available.