offered, ranging from 15 to 17 inches. In addition to the standard-length model, there was also a long wheelbase (LWB), ('Lang' in German) version of the V8 (refer to the infobox for differences in dimensions). It was assembled at Steyr-Daimler-Puch factory in Graz (see production figures). This tradition would continue with the A8, offered in "A8L" format (though only in year 2010 A8L reached the size of the V8L). A once-off experimental Avant (estate) version was built for the wife of former Audi CEO Ferdinand Piech. This car is no longer on display at the Audi Forum Ingolstadt, but in storage in Neckarsulm. Powertrain Powertrain detail of the Audi V8 featured one of two all-new, all-aluminium alloy engines – both petrol engines, and both in V8 configuration with 32 valves (four valves per cylinder) with dual valve springs, and four overhead camshafts (DOHC). The design set the pattern for future Audi-developed Volkswagen Group V8 engines. In addition to using an all-aluminum alloy cylinder block (when the established material was grey cast iron), the camshafts were driven using a hybrid method. A rubber/kevlar toothed timing belt, driven from the front of the crankshaft operated only the exhaust camshaft in each bank. The inlet camshafts were then operated via a simplex roller chain from the exhaust camshaft – the right bank, (cylinders 1–4) at the rear of the engine, and the left bank (cylinders 5–8) at the front of the engine, immediately behind the timing belt. This method reduced the complexity of the timing belt layout, and as a result, required fewer components, such as idler rollers and guides, and led to easier and less costly maintenance of the timing belt and associated components. The intervals for changing the timing belts varied; the 3.6 V8 (PT) required changing every , whereas the 4.2 V8 (ABH) had a longer interval at . A thermostatically controlled electric cooling fan also became standard, replacing the engine-driven viscous fans on earlier cars. This not only provided forced airflow for the engine coolant radiator, but also for the smaller engine oil cooler. Audi's 'trademark' quattro permanent (or semi-permanent, dependent on gearbox type) four-wheel drive system was the only offering for the drivetrain. This normally distributes the engine torque as a 'default' 50:50 between front and rear axles, but can automatically dynamically apportion up to a bias of 20:80 to 80:20 front and rear. The automatic transmission utilizes