Lift and coast: saving fuel without losing the place

Saving fuel costs lap time, and the only question worth asking is whether it costs less than the pit stop it avoids. That is arithmetic you can do before the race rather than a decision to make under pressure at lap thirty.

The sum that decides it

A pit stop costs the pit lane time plus the stop itself, typically 25 to 35 seconds depending on the circuit and the service. If saving enough fuel to skip a stop costs you two tenths per lap over 40 laps, that is 8 seconds against a 30 second stop, and the answer is obvious.

The saving itself is smaller than people expect. Lifting 50 metres before your normal braking point at four corners per lap typically saves something between 2 and 5 per cent of fuel, which over a 40 lap race is one to two laps of range. That is enough to change a strategy and not enough to invent one.

The cost is also measurable rather than felt. Lifting 50 metres early at 200 km/h means coasting for about 0.9 seconds at falling speed, which costs roughly one to two tenths per corner. Four corners is four to eight tenths, and that is the number to weigh against the stop.

Where to lift and where not to

Lift into slow corners with heavy braking. The fuel saved is proportional to the speed you were going to remove anyway, and the lap time cost is smallest where you were about to brake hard. A hairpin at the end of a straight is the ideal candidate.

Never lift into a fast corner. Coasting into a corner taken at speed unsettles the aerodynamic platform and removes the engine braking that was stabilising the rear, so the cost is disproportionate and the risk is real.

And never lift where somebody can pass you. Lifting 50 metres early in a defended braking zone is an invitation, and one position lost is usually worth more than the fuel saved. Fuel saving is done in clear air, and if you are not in clear air the plan has to change.

The three mistakes

The first is saving from lap one. Fuel burn is highest early because the car is heavy, but so is the value of track position, and a driver who saves from the start usually loses places they then spend the whole race recovering. Save in the middle stint where the field has spread.

The second is not measuring. A driver who lifts by feel saves an unknown amount and cannot tell whether it is enough, and the answer is to fix the lift point precisely, run five laps and read the consumption per lap rather than the total.

The third is short filling without a plan. Taking less fuel to save pit time is a different strategy from lifting and coasting, and combining them without arithmetic is how a driver ends a race coasting to the line two laps early.

Making it a plan rather than a reaction

Work out three numbers before the race: consumption per lap at race pace, tank capacity in laps, and the pit stop time at this circuit. From those, the number of stops is fixed and the amount you need to save to remove one is a subtraction rather than a guess.

Then decide the corners in advance and practise them. A driver who knows they lift at turns 3, 7 and 12 executes it without thinking; one who decides mid race lifts at the wrong corners and loses more than they save.

And remember what the rules require. Where a series enables a tyre compound change requirement, participants must pit and complete a full race lap on at least two different dry compounds, and failure to do so means disqualification, which makes a strategy without a stop impossible regardless of fuel.

Sources

1. iRacing, official sporting code including pit and compound rules
2. iRacing, official car setup guide

Frequently asked questions

Is lifting and coasting always worth it?

Only when the total lap time cost is less than the pit stop it removes. Do the subtraction before the race rather than during it.

Where should I lift?

Into slow corners at the end of straights, where you were about to brake hard anyway. Never into a fast corner and never where you can be passed.

How much fuel does it actually save?

Typically 2 to 5 per cent with four lift points, which is one to two laps of range over a 40 lap race.

Can I plan a race with no stop at all?

Only where the rules allow it. A series with a tyre compound change requirement forces a stop and disqualifies anybody who skips it.