Well actually its not the big red thing that pushes the pistons into the pad into the rotor. The big red thing just sits there and allows the other moving pieces i.e. pistons, pads, fluid, and rotor to do their jobs. The system functions by the driver's depressing the brake pedal which increases the brake line pressure which is transferred by the brake fluid to the pistons (held in place by the big red things) causing them to extend out against the pads causing the friction material to clamp the rotor and finally stop the vehicle. The caliper is merely a stationary base to apply the force from. Engineers design performance calipers to hold more or larger pads which require additional pistons to ensure uniform application of pressure across the surface of the larger pads. Larger pads generally provide a larger swept area on the rotor and therefore they are capable of creating more friction under the same pressure load.

The process of stopping is basically the conversion of rotating energy into heat energy. So it stands to reason that a brake system capable of efficient heat management will stop better than a less efficient system. Larger rotors will provide more surface area to dissipate heat energy and will therefore perform better than smaller ones using the exact same caliper and pad combinations. Larger diameter rotors also permit the rotor to be clamped further from the center of the rotating mass which increases leverage and also contributes to better stopping performance. Note: Increased diameters will generally increase the rotating mass and mitigate the full performance advantage if lighter performance rotors are not selected.

And that's why a 350mm rotor with a stock Civic caliper will stop better than a stock diameter rotor with a Civic caliper.

There are many variables that influence brake performance and while "the big red things" do facilitate the use of larger pads, which generally improves performance there are other less expensive alternatives that may have a larger impact on your braking performance such as brake pad and tire selections.

 

Well, so much for my original question about whether there are OEM-replica rotors for the Evo VIII or retailers who sell the OEM rotors at a discount.

The conclusion appears to be as follows: a) nobody knows of an OEM-replica rotor; b) nobody has found the OEM rotors at a discount. If I'm wrong, please let me know.

Neal, you earned your little battle about rotors and calipers by using my post as an opportunity to pitch a product that isn't responsive to my original inquiry. You changed the subject.

 

I take full responsibility for ruining this post, no one else. Ryanmcd2 offered great assistance and did not aid in the chaos one bit. I was in the wrong and will remember for future posts.

 

Actually there is a replica of the original OEM disc from Bradi wich is considered a lot better than the oem disc and it's used by a large number of gr. N rally teams in Europe.

Bradi Gr. N disc pic...

I got my bradis for an excellent price from Express parts http://www.expressparts.co.uk/ contact Paul.

plus oem pads are considered cr@p, go for pagids 4.2's or ferodo 2500.

good luck

 

Thanks a lot for the info, especially for the link. Excellent.