Audi RS2 B4 — Problems & Common Faults

The RS2 was the first RS and a joint effort: developed and final-assembled by Porsche in Zuffenhausen, in the same hall as the Mercedes 500 E, with the manufacturer on the papers being the Audi/Porsche consortium. That shows in the chassis number, which starts with WAC, while the S2 and Audi 80 start with WAU. 2,891 were built in 1994 and 1995 at 98,900 marks, including around 180 right-hand-drive cars and four saloons. It was never sold in the US and only became legal to import there in 2019. Demand has exceeded supply for years and prices follow: Hagerty values a good RS2 at $71,400 in October 2026, with a range of $62,400 to $87,900, up 5 percent in a year, and the last twelve months of sales averaged $62,200 across seven cars. In the UK a show car makes £80,000 and the average sits around £50,000; in the mid-2000s they went for under £10,000.

The ADU is a 2.2 litre five-cylinder with 20 valves, a bigger KKK turbo than the S2, 1.4 instead of 1.1 bar of boost, hotter cams, a larger intercooler and a fuel pump from the 911. 315 hp at 6,500 rpm, 410 Nm at 3,000. Below 3,000 it is docile, above that the shove arrives all at once and overtaking in the wrong gear gets tricky. Add the throaty note of the 1-2-4-5-3 firing order and the hiss of the wastegate. The engine is considered immensely strong, many cars have over 150,000 miles, and damage comes from neglect and tuning: the stock rods will not take much beyond about 300 hp.

Two things to know. Timing belt and water pump are RS2-specific: a smaller pump wheel, one tooth more, and timing a tooth different from the S2. Use S2 parts or S2 marks and the engine goes together wrong. Audi Tradition supplies belt 034 109 119 C and pump 034 121 004 BX; no fixed factory interval is documented, and in practice they are changed every five to six years. And the periphery ages: the mass airflow sensor with stumbling and black smoke, the coil wiring in the cam cover with a short-circuit risk, the fuel pump under load, the plastic auxiliary water pump, cracks in the manifold, oil coking in the turbo with blue smoke on cold start.

The brakes are the second chapter: magnesium Brembo calipers suffer from road salt, discs rust when parked, rear discs and pads cost £640 from Audi and were on back order. The hydraulic system with pump, accumulator and a booster at around £600 is prone to leaks, a front suspension rebuild runs about £850, the air-conditioning compressor £700 plus at least 16 hours of labour. Gearbox: second-gear synchro on downshifts, linkage bushes, clutch around 120,000 miles. Rust is not an issue, the body is fully galvanised, but the headliner sags. Parts such as bumpers, the tail-light panel and trim are scarce and expensive, and the Dunlop SP Sport 8000 in 245/40 R17 is no longer made.

Test drive: listen for blue smoke and hissing on a cold start, hook up a boost gauge, watch for stumbling under load, watch the red brake warning light, check the power steering pump for leaks, test the rear differential lock below 15 mph. And authenticity: WAC in the chassis number, factory stickers, the consortium plaque, complete papers. S2 conversions with the right engine and gearbox are documented. An E34 M5 Touring steers more precisely and an E36 M3 was the better car in the 1994 comparison test, but neither came out of Zuffenhausen.