The RB4 emerged from lessons learned during the difficult reliability campaign of its predecessor. Geoff Willis joined as a technical strengthening measure, and the pairing of Newey and Willis was expected to yield a more refined and durable package. The car carried Adrian Newey's characteristic aerodynamic thinking and was adapted to the revised 2008 technical regulations, which required the standardised McLaren Electronic Systems ECU across all teams — a measure intended to eliminate driver aids such as traction control and engine braking.
One visible technical experiment early in testing was a pronounced shark-fin engine cover that Red Bull evaluated at Barcelona. Mark Webber ran the car with this fin configuration while David Coulthard used a more conventional rear bodywork arrangement on the same day, reflecting the team's active aerodynamic exploration before the season opener.
Pre-season testing was broadly encouraging. Both Webber and Coulthard were competitive on the timesheets, and the team considered itself well prepared for the Australian Grand Prix. Coulthard had a minor incident touching the wall at Barcelona, and Webber sustained some light chassis damage on kerbs during a separate test, but neither incident significantly disrupted preparation.
A notable subplot during testing was Sebastian Vettel's appearance in the RB4. When Coulthard was unavailable due to a trapped nerve, Vettel — then still driving for Toro Rosso — was invited to test the car at Barcelona over three days in February 2008. He completed 109 laps on the middle day and posted a time of 1:22.558. The session offered an early preview of the relationship that would eventually see Vettel promoted to Red Bull Racing for 2009.
Webber qualified second at the British Grand Prix, where Coulthard announced he would retire from Formula One at the end of the season. The summer months produced inconsistent results. Progress came at the Belgian Grand Prix, where Webber scored a point for eighth after starting seventh. The following round in Italy saw Webber reach third on the grid and battle the top teams before spinning away and finishing eighth.
In Singapore, an unusual mechanical failure contributed to Webber's retirement on lap 29. The team later claimed that an electrical surge caused by a passing underground tram beneath turn 13 of the street circuit prompted the gearbox to engage two gears simultaneously — an explanation disputed by the city-state's railway operator. Coulthard, meanwhile, climbed to seventh in the same race and collected the final championship points of his career. At the Japanese Grand Prix, Webber finished eighth from thirteenth on the grid; Coulthard retired after losing control at the second corner and hitting the tyre barrier.
The RB4 carried Red Bull Cola branding on its bargeboards and rear wing at select races following the beverage brand's launch. At the Brazilian Grand Prix, Coulthard's car wore a special Wings for Life livery — the same spinal cord injury charity the team had supported at the British Grand Prix in 2007 — as a tribute for his final race. The FIA granted special dispensation for Coulthard's car to appear in different colours to Webber's machine.
The 2008 season represented a transitional moment for Red Bull Racing: Coulthard's retirement closed the chapter on the team's early identity, and Vettel's cameo in the RB4 foreshadowed a new era. The technical infrastructure assembled around the RB4 — Newey, Willis, and a maturing design process — positioned the team to take the step forward that would arrive in 2009 with the RB5.