First off I have to mention that I've been lurking on this list for a
week or two, so if I end up repeating something that has already been
talked to death, then please forgive me.
I do own a Dakota, but my comment and experience regarding x-drilled
rotors are actually derived from my car. Additionally, I race my car,
I've read books dedicated to brake system and done countless calculation
revolving around brake upgrades too. Does this make me an authority on
brakes? Hell no, but I do have some experiences regarding brakes that
can likely only be duplicated on a race track so I thought I'd share
them with you.
I personally do not believe that x-drilled rotors of OE dimensions will
help the braking capability of our trucks. The x-drilled rotors will
slightly reduce the area that the pad is in contact with the rotor, but
alone is nothing to worry about. What is of concern is that the holes
in the rotors end up reducing the mass of the rotor, and subsiquently
end up reducing the thermal capacity of the rotor. In other words the
rotor will heat up faster if it is x-drilled. Sure it should cool down
quicker too, but I doubt that any of you actually suffer from brakes
that can't cool fast enough.
Another point is that high temperature alone will not likely warp a
rotor, but a thermal shock will. If the rotor heats too fast or cools
too quick, it may warp. OE rotors are (usually) designed to have enough
thermal capacity to resist heating up too fast. If a rotor is too thin
due to wear or being *turned* (like when getting a break job), then it
more likely to warp due to heating up too fast. Now you take a
x-drilled rotor that has less thermal mass than a stock rotor and you
ask it to stop your truck in the same distance as the stock
rotors...Which one do you think gets hotter quicker? The x-drilled
one. If that thermal energy is too much for the rotor absorb, then the
rotor is likely to crack. Yes, I said crack! I've done this myself on
my car at the track while using race pads. The pads where good to temps
in excess of 1200 deg F, that they overheated the x-drilled rotors and
the rotors responded by cracking. I had never experienced this problem
with the solid (non x-drilled) rotors on my car and I've also never
warped a rotor on the car either. ***An quick way to warp a rotor is to
cool a hot rotor suddenly with water...like at a car wash***
After all the nasty stuff I said about x-drilled version of OE sized
rotors, I have to say that there are good applications for x-drilling.
On many race cars and some sportscars, the rotors are x-drilled, but
they are designed with enough mass to handle a sudden influx of heat.
Then there is slotting. I don't have too much experience with slotting,
but I will say that if you *must* have the cool look of non stock
rotors, then I'd suggest slotting over x-drilled. Slotted rotors are
less prone to cracking than the x-drilled rotor.
The easiest way to get better brake performance is to have fresh fluid
in the system and bleed it occationally (Perhaps every year for the
average Joe). I've had to bleed my brakes on my car before a track
session in the morning and then again at lunch time. The next best step
is to use good pads. I strongly discourage you from using organic pads,
they overheat too easy, instead try finding good semi-metalic pads.
Some friction companies also make carbon-kevlar or carbon-metalic pads
too, but be careful with these pads. They are great at handling high
temps, but often don't provide enough friction at lower temps. They can
also *eat* rotors if not up to temp and produce dust that can easily
damage the finish on rims.
I hope I didn't babble too much - Mike
'93 Sentra SE-R w/mods (Race Car)
'97 Dakota SLT+ CC 4x4 w/318 (Tow Vehicle)
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