IndyCar races are often won on a number the broadcast rarely shows you: the fuel target. It is usually expressed as a mileage figure the driver has to hit, and hitting it, or beating it, quietly decides more races than any overtake.
What the number means
A fuel number is the fuel-mileage target a driver must average to make the strategy work, to reach the next pit window, or to turn a planned three-stop race into a two-stop. When a strategist says the number over the radio, the driver's job changes instantly. They are no longer driving for the fastest lap. They are driving for efficiency, which is a completely different skill.
The lift-and-coast tax
The main tool for saving fuel is lift-and-coast: lifting off the throttle before the braking zone and letting the car roll, burning less fuel into the corner. It works, but it is a tax. Every metre of coasting is a metre you are not accelerating, and it shows up as lost lap time.
The art is in where you pay the tax:
- Lift before a heavy braking zone, where you were going to slow down anyway, and the time cost is small.
- Lift on a flat-out section and you bleed lap time fast for little fuel saved.
- Save the throttle on corner exit onto a long straight, and the top-speed loss compounds all the way down the following straight.
Good fuel-savers lose almost nothing per lap. Poor ones haemorrhage a tenth here and a tenth there until a pit-stop advantage evaporates.
The stint math
Here is why the number is worth the pain. Imagine a race that splits cleanly into three stints of fuel. If a team can stretch each stint just enough to cover the race in two stops instead of three, they save an entire pit stop, often twenty-plus seconds of pit lane and a full stop's worth of track position.
One saved pit stop is worth more than a dozen brave overtakes. That is why the calm driver on a fuel number often beats the fast one who ignored it.
The risk is obvious. Push the window too far and you run dry on the last lap, handing back everything. Strategists live in that tension, updating the target lap by lap as the race unfolds.
When to gamble
Fuel strategy is at its most thrilling when a caution period changes the math. A well-timed yellow lets a car crawl around at low speed, banking fuel and turning an impossible number into an easy one. Teams that gamble on stretching a stint just before a likely caution can leapfrog the entire field without passing a soul on track.
So next time a driver who has not led all day suddenly appears at the front in the closing laps, do not assume they got lucky. Look at the fuel number. Someone did the math, held their nerve, and won the race in the one place the cameras never point: the exit of the corner, foot easing off the throttle, saving just enough.