Master Cylinder comparison

[BFS57]

Hello;
OK, I guess I'm experiencing a bad master right out of the box! But my question has to do with the bore size of masters between 1&1/8", 1", and 15/16".
Does anyone know what would happen if I bolted a larger bore or smaller bore size master to my car that had a 1" bore on it? What would the difference make my brakes work like?
I know that the masters I am being given are for non power brakes (longer push rod hole inside) than the power brake masters with a larger bore size and the booster pushes right at the end of the piston.
Bruce

[kb426]

Larger bore, more volume, less pressure.

[chimp koose]

smaller bore,higher pressure ,longer pedal stroke required

[Mac]

A larger bore like 1 1/8" would be for a 4 whl disc system for instance. Disc / drums somewhat less. Drum / drum even less. Calipers need more volumn that whl. cyls.

[PeterR]

my question has to do with the bore size of masters between 1&1/8", 1", and 15/16".
Does anyone know what would happen if I bolted a larger bore or smaller bore size master to my car that had a 1" bore on it? What would the difference make my brakes work like?
Bruce

Compared to the 1" bore

15/16 bore has
88%  pedal effort and 114% pedal stroke

1-1/8 bore has
127% pedal effort and  79% pedal stroke

[enjenjo]

Another way of putting it, in addition to mechanical ratio, a brake system has a hydraulic ratio. Simplified, if the master cylinder is 1 sq in, and the wheel cylinders total 6 sq in, your ratio is 6 to one.Iincreasing the bore of the master cylinder by 27 percent mades the new ratio 5.3 to one. Decreasing the bore by 12 percent makes the new ratio 6.4 to one.

You also have to consider the displacement of the master cylinder versus the displacement of the wheel cylinders/calipers, allowing for expansion of any hoses in the system. The displacement of the master cylinder has to be higher than the displacement of the wheel cylinders under all conditions, or even with the system operating properly, you may not be able tio fully apply the brakes.