The BT53 was visually and mechanically similar to the final 1983 BT52B, but incorporated larger sidepods for improved cooling and repositioned turbochargers and intercoolers to improve fuel efficiency. The latter change was necessitated by the ban on mid-race refuelling introduced for 1984, which required the car to carry an enlarged 220-litre fuel tank for the full race distance. The turbocharged BMW M12 engine produced approximately 900 bhp in qualifying trim and was de-tuned to around 800 bhp for race use, making it one of the most powerful cars in the field at the time. During qualifying for the South African Grand Prix, Piquet recorded 325 km/h on Kyalami's 1 km straight — the fastest speed trap of the 1984 season. Like the other cars on the grid in 1984, the BT53 adopted small winglets on the end plates of the rear wing, a development pioneered by Ferrari in 1983.
Piquet was the reigning world champion and team leader. The second seat was filled by Teo Fabi, who shared the drive with his brother Corrado due to Teo's ongoing commitments in the North American Champ Car series with Forsythe Racing. Teo had qualified on pole for the 1983 Indianapolis 500, becoming only the second rookie in the race's history to do so. Corrado substituted three times during the season: at Monaco (when Teo was racing at Milwaukee), and at the Canadian and Dallas Grands Prix (both clashing with Champ Car rounds at Portland and Cleveland). At the season finale in Portugal, Teo missed another Laguna Seca Champ Car race and was replaced by Manfred Winkelhock.
The Fabi arrangement reportedly arose from pressure by Brabham's main sponsor Parmalat, an Italian dairy company, which insisted on an Italian driver alongside Piquet after Riccardo Patrese departed for Alfa Romeo. Ecclestone settled on Teo Fabi as the strongest Italian candidate available, with the shared arrangement enabling him to honour his American commitments.
Piquet did not score his first points of the year until Round 7, the Canadian Grand Prix, after retiring from the opening six races with engine, electrical, or turbocharger failures. His win in Canada was followed a week later by victory at Detroit. Those were Brabham's two wins of the season.
McLaren was dominant throughout 1984. Niki Lauda won the title and Alain Prost finished second by half a point, with the two drivers taking twelve victories between them using the Porsche-built TAG V6 turbo in the John Barnard-designed MP4/2. Piquet could not realistically contest the championship against the McLarens' consistency, despite regularly out-qualifying them. He took nine pole positions across the year — more than any other driver — underscoring how quick the BT53 was in low-fuel trim. Prost was the only McLaren driver to claim a pole position in 1984, doing so three times.
Reliability improved in the second half of the season, allowing Piquet to accumulate points and ultimately finish fifth in the Drivers' Championship. The fundamental problem was the BMW turbochargers rather than the engine block itself, and repeated failures in both qualifying and races limited what was otherwise a fast and well-developed package. The BT53 was replaced by the BT54 for 1985.
The BT53 represents the apex and the ceiling of Brabham's turbocharged BMW era. It was fast enough to win races and dominate qualifying but too fragile to challenge for a second consecutive title. The car demonstrated that Brabham and BMW had a technically competitive partnership; that the 1984 championship belonged to McLaren was a function of the TAG engine's superior reliability rather than any fundamental deficit in Murray's design.