As I was told by one of the guys in chassies, there are several factor involved in the brake system design.
Weight of the car, friction cooefficient, size of the intended tires, center of mass and so on.
Once all that is done, the master cylinder and ratio of front to rear is mixed. Then the amount of pressure to activate the system is measured. Then the guys compares that against the PDD or CTS.
The booster is selected to provide reasonable braking with reasonable foot pressure.
Remember, This is very old info.
For the most part, components in a car or truck are selected by :
1. Price.
2. Across the board use.
3. PDD or CTS.
4. Functionallity.
The whole reason the brake booster was design the way it was because it was cheap and they, car makers, needed to improve their rotten braking systems.
The vacuum of the engine was untapped as a "power source".
In the 70s you had vacuum HVAC controls. brakes and interior adjusters.
I undertand they even had vacuum assist windows ( wonder if Bill Gates knows this )
