Why Is There A 'Blow-off Valve' On This SUSPENSION Setup?

The LMP2 class is in its twilight year, but the technology used on this and similar prototype cars is still industry relevant and interesting as we discuss in this [TECH TALK]

Fun fact, LMP2 class cars were FASTER than LMDH, LMH and GTP before more class restrictions were put in place in 2020.

Care of Jota Sport's old LMP2 class car, Andre is going to run you through some of the basics of a high-end dedicated race car where the suspension doesn't just need to respond to driver and track surface inputs but also potentially large amounts of downforce. It is the race engineer's job to find the smallest amount of compromise between each to give the driver the tool he needs to get around the track as fast as possible, and in the case of endurance racing for hours on end.

First up, some of the basics are covered on this 4-way adjustable suspension where bump and rebound are set for low and high-speed inputs, which relates to driver and track input rather than the velocity of the car. This system features a Blow off Valve to keep the car settled, and this can be set up for specific corners on a track where the quickest route might see the driver consistently hitting the curb lap after lap.

Linear travel potentiometers are used on the suspension, and along with data from elsewhere on the car, these will be used by the race engineers to figure out what they should change and adjust to suit the track, conditions and/or driver.

So far, all of this is not hugely uncommon, but where this LMP2 car and many other dedicated professional-level vehicles are different from the lower echelons is via the third/heave element or 3rd member. Simply put, this acts as an anti-roll bar and also handles the downforce produced by the car's aero. Without it, the downforce would push the car into the ground at speed, or the suspension would be so stiff to compensate for this at low speed, it would compromise performance.
------------------------------------
TIME STAMPS:
0:00 - Oreca LMP2
0:19 - Dampers
0:43 - Low-Speed Adjustment
0:53 - High-Speed Adjustment
1:03 - Blow Off Valve
1:36 - Damper Tuning
1:55 - 3rd Element
2:56 - Anti-roll Bar Application
3:29 - Torsion Bar/Anti-roll Bar Adjustment
3:36 - The Goal: High AND Low-Speed Performance
3:54 - Subscribe, Like, Get A Perm, Etc Etc