Part 2 IMSA: Where you win and officials screw you out of it.
To try and balance the refueling process on the stopwatch, IMSA makes use of refueling flow restrictors. Like an air restrictor that allows more or less air into an engine's combustion chamber, the refueling restrictors are placed in the hose that connects from the large refueling tanks to each car. For cars with smaller fuel cells, refueling restrictors with smaller openings – to slow the fueling process – are mandated by IMSA.
For cars with bigger cells to fill, restrictors with wider openings – to speed up the process – are specified.
Although it isn't an exact science where every car takes precisely the same time to fill, IMSA's refueling BoP efforts are intended to level out any obvious refueling time advantages or disadvantages across the various models.
With the refueling restrictor sizes for each model issued in the pre-race BoP technical bulletin, teams install the hose restrictor, which is inspected by IMSA, and then the hose/restrictor is sealed by the series to prevent tampering.
TRACKING
Like the live performance data streaming during a race from each car to IMSA's computers, the series also places a sensor in each refueling tank to measure the amount of fuel it contains and the speed that fuel enters the car.
By starting with a known amount of fuel in the refueling tank at the beginning of the race, IMSA's live level sensor reports back in an instant with how much fuel went into the car at each stop, and how long it took for the fuel volume to change.
As an example during a stop, IMSA will see a change from 300 liters to 250 liters, know that 50 liters went into the car, and the data system will also calculate the time it took for the decrease from 300 to 250 to happen. If the flow rate is clearly faster than the number IMSA has calculated for each model, alarms will be raised.
Keep in mind that while IMSA goes to great lengths to apply BoP to refueling speeds with the fueling equipment on pit lane, if a car has a fuel cell that has been optimized to receive that fuel faster than other cars, the flow rate will increase.
Just as reducing aerodynamic drag will improve top speed, reducing blockages in the car's fuel cell will improve its refueling speed. It's an age-old practice carried out by teams in every series where refueling takes place. And some teams are better at it than others.
Last edited by senor honda; 02-06-2018 at 07:59 PM.