It’s the start of the NTT IndyCar Series’ three fastest days of the year as engine technicians from Chevrolet and Honda dial up the turbocharger boost for Fast Friday at the Indianapolis Motor Speedway.

The practice of moving to high boost — the same 160kpa/23.2psi — with the 2.2-liter twin-turbo V6 engines has been done for many years to raise qualifying speeds, and with the need to give teams and drivers a chance to sample the extra 40-50hp ahead of qualifying weekend, IndyCar gives its entrants the option to use high boost throughout the 12-6 p.m. Friday session.

One interesting note is the aforementioned high boost option; teams are not required to start Friday with their engines making maximum power. As we often see, some teams will opt to use the first hour or two of Fast Friday to continue working on race setups at the lower race-boost setting before towing back to their garages and making the necessary chassis setup changes to perform qualifying simulation runs.

The method used to make more horsepower is done through manipulating the turbocharger wastegates which are attached to the exhaust system. Used to regulate how much boost is allowed to be generated and send through the intake plenum and into the combustion chambers, the wastegates play a central role in manufacturing road course power at the Indianapolis Motor Speedway.

Take a look at the hidden gems and how engine techs and teams interact with the wastegates below, or click here: