Drafting in stock car racing exploits the aerodynamic relationship between two vehicles running close together at high speed. The lead car pushes through the air and leaves a low-pressure wake behind it. A trailing car running in that wake experiences reduced frontal drag, allowing it to accelerate without a corresponding increase in engine effort. Simultaneously, the trailing car pushes high-pressure air forward, reducing drag on the rear of the lead car as well. Both cars therefore run faster than either would alone.
The slingshot takes advantage of the momentum built up while drafting. A trailing car — often pushed by a line of additional drafting cars behind it — accumulates excess speed relative to the car ahead. When the time to pass arrives, the driver steers outside, away from the lead car's wake, carries the extra momentum around the high line of the track, then cuts back down across the lead car's wake. Running downhill on the banking and crossing the aerodynamic drag-minimum zone allows the trailing car to carry sufficient speed to complete the pass on the inside of the leader.
Drafting as a race strategy was discovered by stock car racers at the 1960 Daytona 500, when Junior Johnson found that running closely behind another car compensated for his Chevrolet's raw speed deficit against rival machinery. Johnson used the technique deliberately to win the race, becoming one of the first drivers to treat aerodynamic cooperation as a tactical weapon.
As other drivers and teams experimented, the emergent properties of the slingshot maneuver became apparent: a line of cars could sustain speeds higher than any individual car could maintain alone, and a strategically timed break from the draft could produce a decisive pass.
The introduction of restrictor plates at Daytona and Talladega in 1988 fundamentally altered the dynamics of the slingshot. Plates limit engine air intake and equalize power output across the field, which means cars no longer have sufficient horsepower to maintain draft speeds once they exit the slipstream. The traditional slingshot — pulling out, accelerating, and clearing the car being passed — became difficult to execute cleanly because the passing car, once outside the draft, lacked the power to drive definitively past the car it was challenging.
This shift produced new passing techniques. Side-drafting, in which a driver pulls alongside another car to rob it of clean air by disturbing the airflow around its sides, replaced the classic slingshot as the dominant passing strategy at restrictor-plate venues.
To compensate for reduced individual horsepower, drivers at Daytona and Talladega adopted bump drafting, in which a following car makes physical contact with the rear bumper of the car ahead, pushing it forward to maintain combined speed. The tactic was popularized in part by the Archer Brothers in SCCA competition during the late 1980s and became widespread in NASCAR.
A more extreme evolution, known as tandem drafting or two-car drafting, emerged around 2007. Kyle Busch discovered during a Talladega test that having Ryan Newman push his car from directly behind produced a two-second per-lap advantage over normal pack drafting. At the repaved Daytona International Speedway in 2011, the smooth corners allowed tandem pairs to maintain locked contact throughout the entire circuit. During the 2011 Daytona 500 and subsequent restrictor-plate events, two-car tandems ran 15 mph faster than single cars and dominated race strategy. NASCAR subsequently modified car specifications for the 2012 season to break up tandem pairs and return to pack racing.
The slingshot maneuver and its associated drafting strategies are central mechanics in any sim racing title that models superspeedway aerodynamics. NASCAR-licensed simulations model the wake effect, low-pressure zones, and the handling changes induced by following or leading in a draft — the leading car losing rear downforce, the trailing car losing front downforce, and sandwiched cars losing downforce at both ends. Mastering the timing of when to pull out of a draft to execute a pass, without losing so much momentum that the pass fails, remains one of the core skills in oval simulation racing.