I notice everytime someone asks what a good brake upgrade would be someone always chimes in with "swap the booster and master cylinder from XXX car"

Yet there is never an answer as to WHY this is done...personally i think its a pain in the *** to swap out.

I understand if this is done to fit a certain Master Cylinder...but if its done purely from a booster standpoint....what exactly is to gain from using a bigger Booster? and what exactly does the booster do?

 

When you swap a new booster in you push more fluid, because of this your pedal travels less distance to create the same braking action. Basically you get a better pedal feel, and can push more fluid to aid in hard breaking. Done with a bigger brake combo, you dramatically increase your braking ability.

-Jake

 

How do you push more fluid? The master cylinder pushes the same amount of fluid regardless of what booster is present...it may give you more force but it doesnt give you more fluid

 

SuperHatch more or less described the effects of swapping M/C, not the bosster. The larger booster will make your brakes seem more powerfull but they aren't. The larger booster allows a higher brake line pressure for the same input force(your leg). Ever driven a 1970-80's vintage large american sedan. They are way overboosted so a firm stomp of the bkakes locks up your tires. Personally I would keep the stock booster. Brake feel and modulation are decreased with an increase in boost assist.

 

when you install a bigger master...you decrease your pedal travel, more fluid moved per master cylinder/pedal movement. the same work is done but less work at your foot.

a booster that does more work for you also does nothing but makes braking easier for your foot. the braking capability of the car is determined by the stuff at the wheels, not at your foot.

less pedal travel may help you better modulate the brakes under threashold braking. it also gives you more confidence in your brakes...purely "in your head" kind of upgrade.