Brake the bank: amzn.to/3TLiqnj
Patreon: / d4a
Support d4a: driving-4-answers-shop.fourth...
Never boil: amzn.to/3skjG58
Here's an interesting little piece of information. The amount of heat released by an average car during a single braking instance from a speed of 90 km/h is enough to boil two liters of water in just three seconds. All stock systems on all cars today are capable of doing this at least 4-5 times before brake fade starts occurring. This means that you can accelerate from 0 to 90 panic brake to a stop then accelerate to 90 again panic brake again and repeat this cycle at least 4 times before the slightest amount of brake fade can be measured. And even once brake fade starts it will be small and gradual and getting your stock brakes to fade to a point where they can't lock up the wheels and trigger ABS is next to impossible. This means that driving on the street cannot overpower the stock braking system. In fact if you ever need multiple panic brakes in a row while driving on public roads than there's something very wrong with your driving.
A lack of braking force does not exist on vehicles. Issue number two is that increasing braking force further cannot reduce your stopping distance.
And this is because your tires are the only thing on your car touching the ground...they are the only point of contact between your vehicle and the road surface. Once your overpower the grip that your tires provide there is nothing else left to overpower. Once the tire locks up and starts sliding increasing the brake force further will achieve nothing. Increasing the brake force via increased leverage or increased clamping force cannot increase the grip of the tires.
Increasing braking force further cannot reduce your stopping distance. And this is because we already have more than enough braking force to lock up the wheels. The comments on my previous video is make it obvious that many people associate brakes primarily with friction and torque....but a much better approach would be to perceive brakes as heat sinks. This is what they do. They convert the motion of the car or kinetic energy into heat and then dissipate this heat into the surrounding air.
Now we're going to compare three different cars to illustrate the extent to which modern cars really don't have an issue with braking.
The first one is the Mclaren Senna which is an 800 horsepower hypercar with absolutely amazing brakes state of the art carbon brakes. It has 390mm discs and 6 piston fixed calipers in the front. It gets from 0 to 100km/h in 2.6 seconds. The second car is the Mazda MX-5 ND has 280mm disc brakes and single piston floating calipers in the front. The 2.0 liter model gets from 0 - 100 km/h in just under 7 seconds. The third car is my very own 2009 Toyota Aygo has 247mm discs and single piston floating calipers in the front. It gets from 0-100 km/h in 14.2 seconds.
So as you can see we have staggering differences in brake systems and acceleration times. But not so much when it comes to braking distances. The Senna manages to come to a stop from a speed of 100kmh in 30 meters. The ND MX-5 manages 33.8 meters. I did a little test with the Aygo and did 10 panic brakes from 100 km/h and I managed an average of 35 meters.
So the McLaren Senna has 57% larger brake discs than the Aygo and has six times the number of caliper pistons. It is also 446% faster from 0 to 60 than the Aygo but it is only 16 % faster from 60 to 0.
So why is this the case? Why doesn't a million dollar hyper car dramatically outbreak a cheap little city car? The reason is that technology has long since reached the sensible limit of braking force.
Getting to a stop from 100 km/h in 35 meters takes less than 3 seconds and this in turn exposes you to forces of nearly 1G. Which is the limit of what the average driver can sustain on their body and still retain full control of their car.
Engineers are more than capable of making vehicles with ridiculous stopping distances. For example the F2004 which is Ferrari's formula 1 car from the 2004 season can come to a stop from 100km/h in just 16 meters. That's more than 2Gs of force. Formula 1 drivers are highly trained athletes capable of taking this load easily. On the other hand 2Gs would make many average drivers loose control of their vehicle. In fact F1 cars can generate as high as 5Gs of force when braking hard from high speeds. That's the sort of deceleration that can make some people pass out.
A special thank you to my patrons:
Daniel
Pepe
Brian Alvarez
Peter Della Flora
Dave Westwood
Joe C
Zwoa Meda Beda
Toma Marini
Cole Philips
#d4a #bbk #brakes