Page 1 of 2 Next >> For the first full season running the highly anticipated BMW turbo engine, Brabham's chief designer Gordon Murray decided to start early, and before the end of 1982 the all-new BT51 was already being extensively tested. Unfortunately, the 1983 Brabham was rendered obsolete with a stroke of the pen, when ground effect aerodynamics were banned at the very last minute by making a flat-bottom floor mandatory from the start of the 1983 season. Most teams dealt with the late rule changes by adjusting their existing 1983 design but, despite already having tested the BT51, Murray decided to start with a clean sheet.
On his second 1983 design, dubbed the BT52, Murray completely eliminated the bulky 'side pods', which housed the radiators and more importantly also provided the crucial surface area for the now banned under-body aerodynamics. Instead, Murray concentrated all the weight over the rear wheels to provide additional traction for BMW's powerful engine. The radiators were mounted on either side of the engine and were bolted onto the rear subframe. This enabled the mechanics to remove the complete rear end of the car complete with fluids, allowing for much quicker and easier engine changes. The front suspension also formed one separate unit, so the BT52 consisted of three major components.
While the car in its entirety was very much a radical design, Murray remained conservative with the chassis construction. Where others had opted to construct their tubs from carbon-fibre composites in their entirety, the BT52 still combined a conventional sheet aluminium bottom half with a carbon-fibre top half. More composite sections were used than on the earlier 'hybrid' Brabham chassis but Murray was still not convinced a full carbon fibre tub could safely withstand a high speed impact. With double wishbones and push-rod actuated coil springs over dampers, the front and rear suspension was also conventional. To make up for the downforce lost due to the ground effect ban, sizeable front and rear wings were fitted.
First raced halfway through the 1982 season, the BMW turbocharged engine had already shown great promise but still lacked consistency, which was one of the reasons Murray tried to get a head start. Dubbed the M12/13, the four-cylinder unit was actually based on a production engine; some engines were even built with well run in blocks that had covered over 100,000 km and were sometimes retrieved from scrapyards. The stock cast-iron block was fitted with a bespoke alloy head with four valves per cylinder. A KKK turbocharger helped boost the power to 640 bhp in race trim and well over 750 bhp in qualifying. The BMW engine was mated to a Brabham gearbox with Hewland internals that had five or six forward gears depending on the circuit. Page 1 of 2 Next >>