my car ( XKR 4.2 year 2005 with 20" wheels) has Brembo brakes with drilled and ventilated discs.
I would like to increase the diameter of the discs (front and rear) while maintaining the original Brembo brake calipers.
Do you know if anyone has done this?

 

Standard brake discs on the 4.2 are 305mm diameter Front and Rear whilst Brembo are 355mm Front and 330mm Rear.

I understood the limiting factor on diameter is clearance within the wheels apart from the fixed Brembo caliper making any increase in disc diameter difficult.

I'll also be interested to hear if anyone has fitted larger discs and what benefit this achieves in combination with the original sized caliper and pads.

Graham

 

Don't think you can, other calipers are needed, big bugs.

Another way to get better stopping power is via better brake pads. I just love the Pagid RS15 I have now, but they can squeal (disadvantage of all pads with a higher friction coefficient).

 

Does brembo offer a compatible composite/ceramic disc? I saw them on "How Stuff is Made" and want them now. lol

 

Yes, at $31k for the kit and only for a handful of cars.

StopTech at one time ventured into carbon ceramic brakes. The rotors alone were $10k.

 

Yeah.

That's not gonna happen.

lol

 

Does anyone know why ceramic brakes are SO expensive? I mean, the raw material is basically just... sand.

 

Marketing, man. Marketing.

 

What is the OP after?

Surely once your brakes operate the ABS system you are at maximum braking, regardless of the system in use!

The only way to improve the stopping distance would be better tyres/suspension etc. !?

 

Brick wall? Telephone pole? The options for shorter stopping distance are endless!

 

I have Brembo brakes on my 98 Coupé with standard Jaguar pads , they work just fine but I have a couple of mates that use Ferodo DS2500 pads and they report much improved braking with no fade ,

Hope this helps

NikasilNik

 

You could always upgrade to the Alcon 6 piston calipers.

 

Stopping distance obviously is primarily from the tires (for street the Michelins Pilot Super Sports are great for this, including acceleration ;-)). Braking can be improved in 2 ways, 1) that you can easier modulate the braking force yourself which helps also with a quicker response and 2) under heavy usage brake fade can occur lowering braking force on the wheels. So both have an effect on stopping distance, as they determine how quick and well the right amount of torque is applied to the rotors to handle the maximum braking force for the wheels. So this is also where brake pads play an important role.

Attached is info from stoptech that roughly categorizes some pads, so you have some idea. Also as a general rule of thumb, initial cold bite goes down for Club and more so from the race category as these are built to operate at higher temps. One exception though which is the RS15, that one has a very good initial bite already to start with, making them also usable for street conditions.

Here is friction/operating temp info from pagid:
http://www.brakes-pads-discs.co.uk/pagid/material-specifications.php

Whilst experimenting with different pads, have also experienced how important brake balance is between front and rear, so whatever you do, make sure you keep that in mind, any change to the fronts must also be accompanied with work to the rear.