These were invented to take the kinetic energy from the springs and convert it to heat. We know whether it's our street cars or race cars, when the tires hit bumps, holes, curbs or any obstruction, the oil and gas take the jolts out of the ride and help maintain tire contact patch. We also know the gas is what stops "cavitation," which is essentially boiling the shock oil.
In a shock like a ProShock "aluminum threaded body" ones, after about 6 laps the car changes as the shock heats up, the viscosity of the oil deteriorates and the shocks fade, and at times you'll see a film of oil on the shaft because the seals also fail.
Today though, shocks are no longer "shock absorbers." Their gas pressure is reduced or even removed, the piston orifices reduced to pin holes, and the valve stacks thicker to slow piston speeds down. The shock is no longer a shock.
If you attend races with late models, super late models, even NASCAR tour type mods and other cars, sometimes you'll see them all bounce or "porpoise" around the track, some exhibit a bounce in the rear too. What you are witnessing is the tires becoming the shocks and even springs! All a tire is essentially nothing more than a rubber band / rubber ball with air in it. The tire was not created to be the shock/damper absorber.
So the tires get heated up quickly, get softer from the heat generated from excessive loading and slipping, and for a few laps get gummy and you click off quick laps. Come race time you drop your fast times, the tires degrade, lose all ability to generate grip, and you're on ice skates till the end or caution time and maybe fire a fresh set on. Problem is all the conditions still exist, but hopefully they do not degrade enough before the checkers fly.
Many shock builders and factories offer super tie down shocks. They lock the car down and there is no longer anything to absorb the shocks to the tires. And shock package pricing has become outrageous. Anywhere from 2000.00 to 8000.00 in shocks that are no longer shock absorbers.
We hear "the tracks have no grip," "the tires are no good," the excuses are everywhere, some even blaming crate engines. That is all a bunch of BULLSHIT. The issue is these set ups, no matter what you call them or the style you use. Bilstein and other companies did not invent their products to stop travel or hold the car down. In order for these new shocks they have you using, it requires slow entry and late exit. It's why everyone with this shit is on the bottom, it is the only reason why you have zero grip. It's not track surface or anything else.
I now have 5 cars with my full set up including over the counter shocks, 3 with AFCO 14 series, and have set fast times and won against those with tie down shocks and packages between 2k and 8k in shocks because my guys have shocks that are exactly what they were invented for. Shocks are shocks, springs are springs, and tires can be nothing more than tires.
Add in big bars, front ends locked down or locked together, suspension components attached to the car to limit travel, and you have a 2600 to 3000 pound gokart. Many have spent hundreds of thousands of dollars and yet most are field fillers or "close enough," because you do not have the newest shock package the house car has.
People forgot to think, do not question their builders or crew chiefs. Those who build almost build identical cars, some change their lower a arm design or something so they are not carbon copies, but all of them can't even run a 200 lap race without a hand out caution(s), drop in lap times a second or more from qualifying, most can only pass leaning on the outside car because 8 is better than 4, or they gotta pop the guy in the ass to move him up to sneak by on the bottom at half speed with their 200k wind tunnel car.
When you look at the whole picture, there's less cars, there is less people, and the gimmicks and parts they push do nothing. These past 25 years racing as a whole has suffered, quality has suffered, and tracks are losing cars.
There is a correct way to race and be fast, competitive, win and consistent, and it won't break the bank. These chassis builders are getting wealthy on over priced cars that are not mechanically correct, having you buy useless parts like "center pull" arms which do not pull anything but your prick and your bank account. They work the same way as standard trailing arms. Then add in twist axles which, when they decide to break, you end up spun around and in the wall and at times you collect others, rubber biscuit bars or the Hamke styled hidden slider in the right rear trailing arm to allow the rear to be cocked while your foot is in it and it wants to push the nose through the fence. The list goes on.
Stop the nonsense and cars will return, race quality will come back, competition cautions won't be necessary, and the bull shit lame excuses will stop. Let the suspension work, let the shocks just be what they were invented to be, and let the tires just be tires, and your tire bill will get cut and overall running expenses cut and guys will come back!