S2 standard front disc size

[Tonks4x4]

Hi there what is the standard S2 vented front disc measurments please?

[S2central.net]

276x25 from memory, but http://s2central.net has the definite right answer in tech section

[Tonks4x4]

Thanks paul,

do you know what the standard piston sizes are too?

[goodall]

combined area of the two is 60mm mite be 34 and 26 but im not sure

[Skull]

40 and 45

[Tonks4x4]

Humour me for a min then chaps....

If I have a set of 4 pot AP calipers that will fit the standard S2 disc and each of the 4 pistons measure 40mm diameter.

How do I calculate what braking force this will give me in comparison to a set of porsche calipers?

I understand that i will have more pedal movement...

[goodall]

1st step assume a hydraulic pressure, say 100 Pascal (makes handy to work out)

so if 1 pascal is 1 newton per meter, then F=p*a
for the new calipers 100*[(4*40)*10^-6]=0.016
then you take the force and find the torque T=Fl (l is disc diameter/2)
0.016x(187.5x10^-3)=0.003Nm

do the same for the porsche calipers and disk size and then divide 10 (value given for ap systems performance) by 0.003 (ap number)= 3333.3 and multiply by the torque got by porsche system, if is more than 10 its better less its worse

this all assumes that you will get friction of 1 using the brake pads which isnt going to happen and that all the pressure is applied at the edge and also the pad material is the same, but its good for comparing braking force




oh yea and more pedal movement means more slave area thus more pressure


edited because i made a misstake

[Tonks4x4]

1st step assume a hydraulic pressure, say 100 Pascal (makes handy to work out)

so if 1 pascal is 1 newton per meter, then F=p/a
for the new calipers 100/(4*40)*10^-6=625000
then you take the force and find the torque T=Fl (is disc diameter/2)
625000x(187.5x10^-3)=117187.5Nm

do the same for the porsche calipers and disk size and then divide 10 (value given for ap systems performance) by 117187.5 (ap number)= 0.000085333 and multiply by the torque got by porsche system, if is more than 10 its better less its worse

this all assumes that you will get friction of 1 using the brake pads which isnt going to happen and that all the pressure is applied at the edge and also the pad material is the same, but its good for comparing braking force


oh yea and more pedal movement means more slave area thus more pressure

That was heavy reading after a long day at work.....

So as anyone got the figures for a porche setup???

[goodall]

thing is i just noticed its wrong

now fixed and correct, i hope