All Things Mk5 > Performance Modifications
Going Big Brake
JPC:
I would strongly suggest you speak with dave b. He knows all there Is to know about pretty much every caliper.
I think he mentioned once that the cayenne calipers aren't up to much?
Hurdy:
The Cayenne calipers weigh an awful lot (i know I i've held some!) and the size of the cylinder pots are big too, which isn't good for brake feel. They are designed to go on a 2.5 ton 4x4 and not a 1.35 ton hot hatch. Okay they look good, but as a practical brake kit they would be at the bottom of my list!
DaveB@Vagbremtechnic:
The Cayenne stuff has a total piston surface area of around 56cm through to about 60cm - being honest its not a great pedal, the ideal total piston area is around 49-50 sq cm. You'll find with 6 pots with this piston surface areas that the pistons are split normally 27/31/36 or thereabouts. Even the smallest Q7 caliper is 30/34/38 might not sound like a lot but when you start multiplying the radius by its self and then by 3.142 you get huge volume that the 23.8mm master cylinder on the mk5 just cant push.....
They look rather good though :P
With no seal drag with pressure applied the smallest piston will deploy first, so you can "tune" calipers to feel better, they normally mess around with the smallest piston size to make brakes feel sharp, the bigger pistons will start to apply pressure when the smallest piston has reached the limit of its travel which is normally about 1mm.
Porsche 996TT calipers have a big piston split at 36/44mm but work very well, 38/42mm splits are also good (Ferrari 360/R8 Rear) works. 36/40mm works well on a smaller disc.
Personally the only 6 pots I would fit to my car would be AP CP5555's or CP7041 or Carrera GT rears or GT3 RS fronts, unless you want to blow over 1500 quid on brakes.
Regarding the R500 disc it is what it is, you need some mass to absorb the heat generated - no heat/no braking, even two piece 340-360mm assemblies weigh much more than stock, if you need big brakes its normally because you have a powerful car so corner entry speeds will be higher so you've got a lot of energy to get rid off. Dont forget the potential energy that needs dissipating is proportional to your speed squared so that if you can get to your braking point at 80mph instead of 90mph then its not just another 10mph (12%) you need to get rid off its about 25% more energy.
You pays your money I guess
wizzo:
So what do u conclude dave? i wouldn't be getting much more than stock performance wise with the cayenne 6 pots?
PDT:
I think what Dave is saying is that by replacing the tiny original single pot calipers with a much bigger 6pot caliper you may lose some of the brake pedal feel and increase the pedal travel slightly.
I have now driven 2 cars with this conversion including an R32 we did today and the pedal feel was good, not as sharp as the original brakes but not as dull as some standard vauxhalls I have driven! The stopping power is immense compared to the standard brakes.
In total it comes down to what you want, if you want an extremely well priced kit that also looks :jumping: then the cayenne 6pot kit is very very good as long as you are happy to lose some of the pedal feel. If you double your budget then you can achieve the same stopping power with another kit and retain a much sharper pedal. I have never mentioned pedal feel to the customers that I have fitted 2 kits for on mk5's and they havent reported a bad pedal feel, if anything they have been delighted with the conversion. After all, the ECS stage5 big brake kit uses this caliper and with the same piston sizes, look on the American forums, they go mad for them!
The unfortunate thing with brake kits is that you dont get a chance to try before you buy and they arent the type of product that you can easily buy and sell on if you dont like them. I suggest you work out your budget and needs and buy the kit that suits these factors best.
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