Delta

General Definition

Delta (Greek letter: the triangle symbol) is a term used by scientists, engineers, and mathematicians to denote the change in a quantity compared to a reference quantity. Examples include time delta, pressure delta, temperature delta, and so on.

Formula 1 is heavily technical, and this extends to the terminology used during races. For long-time fans and experts, the jargon becomes second nature, but newcomers can easily become lost. One such term is “delta.”

Delta in Formula 1

Formally, the time difference is expressed as the maximum time minus the minimum time.

In F1, delta is used to describe the time difference between two lap times – whether between two cars or between a lap time and a reference time.

If a driver is going slower than a reference lap time, they have a positive delta, measured in seconds and tenths, hundredths, and thousandths of a second. The delta is used to keep track of a driver’s pace during a session.

Delta in Qualifying and Live Timing

During qualifying, the live feed shows each driver’s delta to the pole position time. If their sector time is a personal best, the delta is displayed in green. If it is the fastest in the entire session, it appears in purple. A yellow sector indicates a time slower than both the personal best and the overall fastest time.

Delta Positive and Delta Negative

The terms “delta positive” and “delta negative” arise most commonly during Virtual Safety Car periods. Whenever yellow flags are waved due to a crash or temporary blockage on the track, the Virtual Safety Car is deployed. During these periods, drivers are often instructed by their race engineers to keep their delta positive.

Delta positive means the driver is travelling slower than a pre-defined lap time. For every circuit, there is a pre-defined target lap time that drivers must respect during a Virtual Safety Car period. When a driver’s current lap time is above that target, the delta is positive.

Delta negative means the driver is below the pre-defined lap time – in other words, travelling faster than allowed. Drivers must avoid going delta negative during a Virtual Safety Car period, or they risk penalties.