There is a time period at race weekends when Formula One teams lose their cars, their own property. After each qualifying session, they are required to take their cars to a place in the paddock, sectioned off by the FIA.
That area is known as parc fermé. It literally means closed park in French which describes well the restrictions within that area. The rules regarding the parc fermé and its conditions are quite difficult. Article 34.2 of the 2018 FIA Sporting Regulation sactions the parc fermé. Its primary purpose is to enable race officials to weigh the cars and carry out other checks deemed necessary.
Teams have to take their cars to this restricted area within three and a half hours after the end of the qualifying session until five hours before the start of the formation lap. However, cars are kept under parc fermé rules for much longer. It starts from the time the car first exits the pit in the qualifying session and ends at the start of the formation lap. Teams are heavily restricted in what work they car carry out on the car.
The list of permitted changes includes adding fuel to the car, tyre changes, bleeding of brakes, carrying out of minor changes to the front wing. These restriction means teams can't make significant alterations between the qualifying session and the race which means there is no real qualifying and race setup.
The only exception occurs when climatic conditions change between qualifying and race. In this case, FIA’s race director Charlie Whiting gives permission the team to make appropriate changes to their machines.
Next to the changes mentioned above, there is, in fact, a long list of possible changes. The modifications made between the qualifying session and race of the Canadian Grand Prix demonstrates what alternations teams are allowed to.
Trumpet potentiometer, RHS front tyre temperature monitoring sensor
Lap trigger support, Intercooler assembly, Parameters associated with the change of the intercooler assembly
Red Bull Racing TAG Heuer:
Rear view mirror lenses
Force India Mercedes:
LHS tower assembly, LHS floor spat, Telemetry coax cable, Front brake friction material
RHS front tyre, Rain light
Scuderia Toro Rosso Honda:
ICE (new), TC (new), MGU-H (new), MGU-K (new), Hydraulic powerpack, Clutch, Cluthc housing, AOT control valve, Telemetry ECU, Parameters associated with the change of the PU elements
ICE (previously used),TC (new), MGU-H (new), Intercooler, Parameters associated with the change of the PU elements, intercooler O-ring
Topbody to rear wing bracket, RHS rear outboard speed sensor, RHS rear brake IR sensor
RHS front top wishbone, RHS front lower wishbone, LHS and RHS front track rod, RHS front upright, RHS front push rod, Upper steering column ,Lower steering column, PAS ,Front side dampers, RHS rear corner barrel nut, Parameters associated with the change of the RHS front corner