Audi rallye Quattro A1
The A1 at the 1983 Portugal.

The rallye Quattro A1 was an evolution of the Gr.4 Quattro, but homologated to fit the new Group B class change coming from FIA. It had it’s first rallye the 1983 Rally Monte Carlo, and the last at the Safari rally the same year. The price for such a machine in 1983 was set to 285 000 DEM.

Generally, the rallye Quattro A1 first introduced the lightweight materials to the rally Quattros, alike body panels, suspension struts and the engine block – actually named A1 from exactly this aluminium usage.

Visually, the lightweight route – as a countermeasure for kitting out a rally Quattro and a reinforced chassis – most noticeable by the extended wheel arches. These new flares integrated air ducts in front of the rear arches to route cold air to the rear breaks. Kleber was now out, and Audi changed for Michelin tires. Matter now had 3 versions of rollcages, in aluminium or steel, depending on the intended campaign usage.

Engine: inline 5, cast-iron block, alu-head, 10V, special steel-conrods.
Capacity: 2145 cc by bore 79,51 mm x 86,4 mm stroke
Compression-ratio: 6.3:1
Power: 340 hp / 6000 rpms
Torque: 414 Nm / 3650 rpms

Early versions fitted with K27 turbos, while some used K26 at 0.8~1.9 BAR. Most significant was probably the use of the motorsport Pierburg mechanical injection. [I hold some uncertainty whether later A1s actually featured Bosch Motronic alike the Quattro A2 -Ed.] Standard inlet- (38.2 mm) and outlet valves (33.3 mm) was changed for 41.1 and 35.2 mm ones. Dry sump and a rubberized Matter & Obermoser fuel tank was positioned in the trunk, and the engine had a heat-treated, forged crankshaft.

Whilst the above applied for the works supply coming from Lehmann Motorentechnic, as a contrast, the Quattros campaigning in the UK and run by David Sutton (Audi Sport UK) had some of their engines builds supplied by Terry Hoyle. Hoyle ran a slightly higher compression ratio, and kept with the Pierburg to obtain a earlier turbo-spool meaning stronger mid-range, a feature sought after for rallye purpose.

The A1 holds many shared dimensions (except for the track width) as for the Group 4 car, but weight is now between 1130~1140 kg. The car was succeeded by the further developed Quattro A2, and seems somewhat short lived, but many cars has been modulary upgraded with the newer parts and body panels.