[s-cars] [urq] S-Car Brake system conversion- Read- no more PSpumpintegration <question>

[Mark Strangways]

Yep,
But factor pressure applied to the pads.
Since stooping power is related to the co. of friction, then you need  
to look at PSI applied to the pads.
This would give a better representation of stopping power.

With out question, the monoblock style of caliper is far better than  
the G60, hands down.
No fade on repeated stops, G60 your lucky to get a few high force  
stops before you get into problems.
I would have it no other way than 4 or 6 pot fixed calipers, lived on  
the edge before with the G60's and thats enough for me.

Mark
On 21-Mar-09, at 4:17 PM, John Cody Forbes wrote:

>
>> Cody Forbes wrote:
>>> Another route is to delete the assist, leave the stock master
>>> cylinder, and increase the size of the brakes. Larger brake pistons
>>> have the same effect as smaller master cylinder pistons - travel
>>> increases slightly, but so does leverage. Perfect excuse for going
>>> for some big reds!
>>
>> I'm a little late on this one, but I just wanted to point out that
>> bigger brakes don't necessarily equal bigger pistons.  The effective
>> piston diameter of a G60 is (surprise!) 60 mm.  All of the 4-pot
>> Porsche calipers I looked at a couple of years ago (including big
>> reds and 996tt) were less than that.  Of course, you're still getting
>> a leverage boost with the larger rotor diameter.
>
> Actually I think you may be mistaken. A 996TT caliper has 4 pistons,  
> 2 36mm and 2 44mm. That would give a total piston surface area of  
> 3553mm^2. A G60 has one 60mm piston. A G60 would then have a total  
> piston surface area of 2826mm^2 - roughly 25% less than the Porsche  
> part. If you factor in however much the pistons move (1mm each  
> maybe?) you can see that the used displacement in the Porsche  
> caliper is indeed more. I can't find the info for a Boxster caliper,  
> but if anybody knows the piston sizes you could think back to  
> geometry class (I had to google it ) and use pi times radius^2 for  
> each piston then add the 4 areas together for total piston area.
>
> -Cody Forbes
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