Braking in the slipstream

[zjn]

I read something about braking in the slipstream, but don't remember where....

The guy was saying that braking in the splipstrem is less efficient with cars relying on downforce (i.e. this week Monza race B with GT3), therefore if you are in the slipstream and not willing to overtake you should
brake earlier
or lift off a bit before the braking point
or exit the slipstrem

I guess the latter one ruins the proper racing lane, so should be the last option.

This may explain why it looks to me that people in front of me braked too much. They are right, while I took more space to reach the proper entry speed, resulting in kissing their bumper

Is it correct?

 

[TumeK5]

You should never enter a heavy braking zone right behind someone anyway, since if you started the straight from farther away from the car ahead, it means you're moving at a higher speed, thanks to the slipstream obviously.

But once you move out of the slipstream, you're affected by drag once again and it helps slow the car down. But it's a very miniscule difference, the bigger difference towards braking distance comes from the approach speed.

TL;DR: Slipstream makes car go more vroom, and more vroom also means more scree in the scree zone.

 

[OJBrit]

You're travelling faster in a slip stream so you need to brake a little earlier otherwise you'll overshoot the corner and hit any cars in front.

 

[pedrocor]

It doesn't matter where you read it, it's absolutely right.
When you're on the slipstream of another car, you are traveling on the "hole" it creates in the air, so you have less drag. Also the wings, body and underfloor of your car handle less air, being less effective. Flat out on the straight, no problem on losing downforce, but braking and turning you will suffer without the extra aero. You will need to brake early (just getting out of the gas on a F1 the deceleration is bigger than full brakes applied on a road car) and turn at lower speed. Still, turning on slow speed corners isn't a big of a problem, because at low speeds it relies mainly on mechanical grip and less on downforce.

 

[Talon16]

It doesn't matter where you read it, it's absolutely right.
When you're on the slipstream of another car, you are traveling on the "hole" it creates in the air, so you have less drag. Also the wings, body and underfloor of your car handle less air, being less effective. Flat out on the straight, no problem on losing downforce, but braking and turning you will suffer without the extra aero. You will need to brake early (just getting out of the gas on a F1 the deceleration is bigger than full brakes applied on a road car) and turn at lower speed. Still, turning on slow speed corners isn't a big of a problem, because at low speeds it relies mainly on mechanical grip and less on downforce.

Everything here.

The same "hole" in the air created by the car in front of you that allows you to gain more speed on the straights (as your car is not wasting energy pushing through the air as much) also very much negatively effects your car's aerodynamics everywhere else... which of course inhibits your car's ability to slow down/stop and turn. This is often referred to as "dirty air." When you hear someone complain about dirty air though the turns, it's because their car isn't getting the downforce it wants because the car just in front is creating a hole in the air.

If the car behind is really pushing to keep up, they are using the beans out of the tires which they will pay the price for as the race goes on. If you think of an extreme example, like an F1 car... obviously the aero on those cars is insane. If they follow too close, the car behind just can't compete as its areo has been largely negated. Often in recent years, the car behind would intentionally stay ~1.5ish seconds back to avoid being in the dirty air... which does not make for great racing (in this extreme example). The areo on the 2022 cars was completely redesigned to mitigate this.

 

[Monkdapunk]

It tells you when you set up a custom race that if you select real slip stream your car will lose grip but be faster like in real life. That's why you see racers "step out" to brake. The strong slipstream setting gives both speed and grip.

 

[zjn]

Thanks everyone.

Lot of things to think about during the race. I guess it overloads the cpu at the beginning but becomes more natural later on

 

[eran0004]

Another effect, which doesn't have anything to do with slipstream, is that the gap between you and the car in front if you is measured in time rather than in length, so when both of you are braking the time gap stays constant but the distance between you will be reduced. A gap of 0.3 seconds at 250 km/h is a distance of 21 meters, but if you brake for a hairpin down to 60 km/h the distance between you will be reduced to 5 meters. This effect contributes to the feeling that they're braking harder than you do, and when accelerating away from the hairpin the reverse of this makes it feel like they accelerate faster than you as well.

 

[zjn]

Another effect, which doesn't have anything to do with slipstream, is that the gap between you and the car in front if you is measured in time rather than in length, so when both of you are braking the time gap stays constant but the distance between you will be reduced. A gap of 0.3 seconds at 250 km/h is a distance of 21 meters, but if you brake for a hairpin down to 60 km/h the distance between you will be reduced to 5 meters. This effect contributes to the feeling that they're braking harder than you do, and when accelerating away from the hairpin the reverse of this makes it feel like they accelerate faster than you as well.

This is a good point...
especially on exit this feeling is demoralizing and triggers bad habit to over-do in entrance on the next lap