Cross drilled vs Slotted Rotors
Cross drilled discs offer an enhanced initial bite (more responsive, especially in wet weather) and greater heat dissipation (reduction in heat induced fade - brake fade) over O.E.M.
Slotted discs offer cleaning of the friction material (Brake pads), but do little in terms of additional heat dissipation. Slotted brake discs do not cool better than cross drilled discs or even standard discs. The face groves will slice the brake pad allowing the pad to bite harder into the disc causing an increase in disc temperatures. This is recommended for competition vehicles to bring pad and disc temperatures up into optimal operating temperatures (race cars warm-up engines, tires and brakes for the best possible performance).
An additional technical note, proper slotting of a brake disc does not run off the outer diameter of the brake surface (this method can promote cracking as all brake discs expand with their release of thermal energy).
Recommending what to use can be challenging, the following should assist you to properly supply your readers:
What type of driver ?
REGULAR STREET - Use cross drilled and good brake fluid.
SPIRITED STREET - Use cross drilled, street sport brake pads, steel braided brake lines, and good brake fluid.
RACING STREET - Use cross drilled or slotted, street sport to mild competition brake pads, steel braided brake lines,good brake fluid, or possibly upgraded brake kit.
AMATEUR RACING - Use slotted, racing brake pads, steel braided brake lines, competition brake fluid, or possibly upgraded brake kit.
PROFESSIONAL RACING - Use upgraded brake kit or, when rules do not permit upgraded brake kits, use slotted, racing brake pads, steel braided brake lines, racing brake fluid.
These are general parameters, if specific information is required please contact our technical department.
Technical Director KVR Performance
*********************************************************************Cross-drilled rotors- get them or not?
You are probably thinking of getting those cross-drilled rotors. Well, you're on the good track cause if your OEM rotors fail from usage or if they warp, you will have to spend about $140 for the new ones from the dealer.
The cross drilled rotors are about $5-$25 more than the OEM ones so why not go for them. KVR is a company that makes these rotors for our cars and if you're a TCCoA member, you may still get discounts on it.
KVR rotors are made of a higher quality steel then the Ford rotors are. The increased cooling effect that cross drilling has on a rotor makes them very resistant to warping. The dual piston caliper with its greater clamping force and larger brake pads can actually put less heat into a rotor. This is due to its ability to slow the car down more efficiently.
If you replace your stock 11.5" stock rotors with KVR 11.5" C/D rotors and KVR pads I am sure they will serve you very well. If you desire more braking performance than that system can offer while staying with 16" wheels I would highly recommend the dual piston 10.8" system.
Here are some numbers in brake testing from 100mph to 40mph w/o factoring wheels and tires:
Stock 10.8" system with single piston calipers = X
Stock Sport/Mark 8 11.6" system with single piston calipers = X+ approx 3% (due to the heat factor)
Dual piston PBR calipers with stock 10.8" rotors = X+ approx 22%
Dual piston PBR calipers with 13" rotors = X+ approx 28%
Four piston AP Racing calipers with 13" rotors = X+ approx 40%
Note: The above numbers are based on the calipers working clamping force, Pad cross sectional area and rotor factors as well as other factors. Pad material for the above comparisons would be of the same compound.