Different brake pads can have different characteristics too. Two performance attributes that change among pad compounds is the friction coefficient (CF) and their temperature capability before they fade. Comparing cheap organic pads to stock Ford type semi-metallic pads and then to premium after market Carbon Metallic type pads shows that their is a lot of performance to be obtained by selecting a high performance pad compound. These pads can keep fade in check by tolerating up to 50-80% higher rotor temperatures before they start to fade!
(*) Disclaimer: Not all available pad compounds are represented. These are five pads pads that I have personally tried and was able to get engineering data on. Data courtesy of Performance Friction and Carbotech Engineering.
Moral: Pads are much cheaper than new rotors and calipers. If you haven't yet tried any of these three pads, I urge you to do so before you spend a lot of money on larger rotors that you may not need.
Warping: Rotor warpage problems may be alleviated by the better CM pads, but it can still occur. Warping with the organic or Semi-metallic pads seems to be caused by metal transfering to the rotor after the pads fade away. The CF changes as the pads fade, and heat is generated but not friction. (Like the dull & sharp drill bit analogy.) This occurs unevenly and warps the rotors. If warping still occurs even with CM pads, it is probably not due to fade, but due to severe and repeated temperature cycling. Solving this requires better cooling, or lower temps through bigger, heavier rotors. (Or maybe just not parking the car with red-hot rotors!.)
Noise & Dust: The real limit on your happiness with the CM type of pad will probably not be fading, but other characteristics like rotor warping, noise or dust. These CM type pads do seem to be a little noisier, and/or dustier than stock FORD, but there is also a lot of variability by brand. Buyer beware.
Stopping Distances: You must decide what symptom you are trying to solve. If you are merely trying to solve fading that's one thing. If you are really trying to shorten stopping distances, that is quite another. Alleviating fade is definately going to decrease your stopping distance. But unless you can hold your front tires at the limit of traction from 80 mph on down, bigger rotors will give you more leverage and should help your car stop quicker. Following are some stopping distance test results courtesy of the Sho Shop and the Southern California SHO Club SHOCAL. Tests include Stock '89 10.1 in rotors w/ SM pads, 10.1 in rotors w/CM pads (SS stock kit), 11.6 in rotors w/SM pads (11.6 upgrade), and 12.5 in rotors w/SM pads.
Here's some more feedback on comparing stopping distances of the two systems from fellow SHO member Joshua Teixeira:
"I did the 96 brake upgrade on my 95. My best stopping G to date is about 1.05 G, and the shortest distance is around 125 feet, from 60-0. The 95 has ABS. This is with all Ford parts - 96 SHO Ford pads, 96 SHO Ford rotors."
"My 89 has unknown rotors (stock 10" diameter) on the front, and a set of PF pads that I got here in Canada at Midas (paid $130 CDN for them, or about $85 US - too busy to bring them in from the US). The best stopping G to date is 1.18 G, and the shortest distance is 111 feet 60-0. There is no ABS. I can stop over and over again until the rotors are glowing red hot, and still click off 1.1 G stops, even with the rotors glowing red like that. There is no brake fade to speak of. The rotors have shown no signs of warping, even after repeating this abuse a few times."
As you can read, there is more than one variable, but both systems can work very well. Note that even red-hot 10 in rotors do not "automatically" warp!
On Using 94 Pads with 96 Rotors:
If you are interested in the CM pads, be forewarned that many of them
do not come in the "proper" 96 rotor size. Many will try to sell you a
smaller pad that also fits the 94 rotors. This is really not that big a
deal. There is a small (10%) swept area reduction compared to the 3/8 in.
larger SM pads. But in switching from the SM to the CM pads, there is such
a large improvement in fade resistance, that I would not hesitate
to run the "too small" CM pads. SHO members with the 96 rotors in the survey
reported an 80% reduction in fade, even though most of them were using
CM pads that were "too small". See the brake survey
results above.
