|Suspension / Brakes / Chassis All suspension, brakes and chassis discussions.|
|06-03-2014, 05:35 PM||#1|
Drives: 2013 2LT RS Camaro
Join Date: Dec 2012
Location: I.E. SoCal
THE ARGUMENT AGAINST CROSS-DRILLED VENTED ROTORS
THE ARGUMENT AGAINST CROSS-DRILLED VENTED ROTORS
Marcus Blair Fitzhugh, © 2007, reformatted for clarity)
They're for looks. OK, maybe removing material is good for reducing un-sprung weight, but that's
It doesn't do anything for heat dissipation. The front discs on my car are vented. They're vented
on every car that I know of. When a vented disc is spinning, it pulls air from the center of the disc,
through the channels (which are called vanes), and out the rim of the rotor. The vanes in a
Mercedes-Benz rotor are also curved. That's because the engineers who design rotors know that
curved vanes move cooling air more efficiently than straight vanes, which are less expensive to
manufacture. This cooling air moves in a radial direction. We can view the spinning rotor as an
efficiently designed air pump.
The cross drilled holes in the disc must aid in this cooling design, right?
Not quite. Let's think about what happens. Air flow follows the path of least resistance. Does
the air that's flowing from the center of the rotor to the path of least resistance go to the wide
open vanes, or make a 90° turn, to holes that are drilled axially in the rotor?
So, since the holes aren't there to pull air in, and they don't aid in pushing the air out, you
may be wondering why they were invented.
Cross drilled rotors were originally designed to cure a problem called
was a problem where pads would overheat, and the binding material (glue) would
melt down and vaporize. This vapor became trapped between the pad and the rotor, making
the pad to float on a layer of vapor. The purpose of cross-drilled rotors
was to allow the gas to
The key word there is “was”. Better high performance pad design has eliminated this problem.
If you simply can't bring yourself to believe that cross-drilled rotors are all hype, consider this.
Why aren't cross-drilled rotors used in
NASCAR, Formula 1, Automobile Club de l'Ouest (ACO),
ALMS? If drilling holes in rotors was the hot ticket, at least one team in one of those
associations would use them.
Some people will claim, "
Motorcycles use them!" This is true, however, if you look carefully at a
motorcycle disc you will notice they aren't vented, motorcycles use solid discs. They can use solid
discs because they carry one eighth the weight of a car. If you drive a 400 pound car, solid,
cross-drilled discs may be an option.
Still have doubts?
Here are some quotes from brake engineers, brake manufacturers, and automotive
publications in regard to cross-drilled, slotted, and plain rotors.
Grooves improve 'cleaning' of the pad surfaces and result in a more consistent brake
Grooved discs have a longer life than cross-drilled discs.
What are the benefits to Cross-drilling, Slotting, and Zinc-Washing my rotors?
“In years past, cross-drilling and/or Slotting the rotor for racing purposes was beneficial by
providing a way to expel the gasses created when the bonding agents employed to
manufacture the pads. However, with today’s race pad technology, out-gassing is no longer
much of a concern.
Slotted surfaces are what Baer recommends for track only use.
Slotted only rotors are offered as an option for any of Baer's offerings.
Darrick Dong; Director of Motorsports at Performance Friction
Anyone that tells you that drilling makes the disc run cooler is smoking crack."
(Mr. Gilliland is a well-known brake engineer in the racing industry and has more than 32 years experience in
custom designing brake systems ...he became the main source for improving the brake systems on a variety of
different race vehicles from midgets to NASCAR Winston Cup cars.)
If you cross drill one of these vented rotors, you are creating a stress riser that will
encourage the rotor to crack right through the hole. Many of the rotors available in the
aftermarket are nothing more than inexpensive offshore manufactured stock replacement
rotors, cross drilled to appeal to the performance market.
They are not performance rotors
and will have a corresponding high failure rate
Cross-drilling your rotors might look neat, but what is it really doing for you? Well, unless
your car is using brake pads from the '40s and 50s, not a whole lot. Rotors were first drilled
because early brake pad materials gave off gasses when heated to racing temperatures, a
process known as gassing out. It was an effective solution, but today's friction materials do
not exhibit the some gassing out phenomenon as the early pads.
Contrary to popular belief, they don't lower temperatures, (in fact, by removing weight
from the rotor, they can actually cause temperatures to increase a little.)
“These holes create stress risers that allow the rotor to crack sooner, and make a mess of
brake pads--sort of like a cheese grater rubbing against them at every stop. Want more
evidence? Look at NASCAR or F1. You would think that if drilling holes in the rotor was the
hot ticket, these teams would be doing it. “
“Slotting rotors, on the other hand, might be a consideration if your sanctioning body allows
for it. Cutting thin slots across the face of the rotor can actually help to clean the face of the
brake pads over time, helping to reduce the glazing often found during high-speed use which
can lower the coefficient of friction.
“While there may still be a small concern over creating stress risers in the face of the rotor, if
the slots are shallow and cut properly, the trade-off appears to be worth the risk, (have you
looked at a NASCAR rotor lately?)
At one time the conventional wisdom in racing circles was to cross-drill brake rotors to aid
cooling and eliminate the gas emitted by brake pads. However, today's elite teams in open
wheel, Indy and Trans Am racing are moving away from
crack prone, cross-drilled brake
in favor of rotors modified with a fatigue resistant slotting process.
StopTech provides rotors slotted, drilled or plain. For most performance applications slotted
is the preferred choice. Slotting helps wipe away debris from between the pad and rotor as
well as increasing the "bite" characteristics of the pad.
“A drilled rotor provides the same type of benefit, but
is more susceptible to cracking
under severe usage
. Many customers prefer the look of a drilled rotor and for street and
occasional light duty track use they will work fine.
For more severe applications, we recommend slotted rotors."
(Note that even though Stop Tech sells both drilled and slotted rotors they do not recommend
drilled rotors for severe applications.)
Why are some rotors drilled or slotted?”
Rotors are drilled to reduce rotating weight, an issue near and dear to racers searching
for ways to minimize un-sprung weight.
Drilling diminishes a rotor's durability and
© 2007 Marcus Blair FitzhughSignal to Noise
Performance Upgrades: CAI Intake, VMAX Ported Throttle Body, RX Catch Can, MRT Axle-Back Exhaust Version 2.0 w/ Magnaflow X Pipe & custom J-Pipes, 1LE Strut Tower Brace, SS Brembo 1LE Brakes Upgrade w/ Hawk HPS Pads & Goodridge brake lines.
Exterior Upgrades: Ceramic Tint 30%, Axis Allies rims 20x9(front) 20x10(rear), Goodyear Eagle F1 SuperCar G:2 Tries 285 (front) x 305 (rear), ACS T-5 Front Splitter, Oracle Lighted Rear Bowtie, rk sport spoiler.
Audio Upgrades: Image Dynamics 10" Subwoofer w/custom leather box, Image Dynamics 5 Channel Amp, Audio Control LC 6, Morel 6.5" Coax Speakers
|06-04-2014, 09:02 AM||#2|
Drives: '10 CGM SS, '02 2500HD, '09 300SRT8
Join Date: Nov 2010
Location: Lexington, KY
My SRT8 300 came with Brembos and slotted from factory...along with a raceday package. My SS will get slotted upon 1st needed replacement.
"My friends call me Chris. Are you my friend?"
2010 CGM L99 2SS/RS - CAI, Elite catch-can, Magnaflow 3", Pfadt springs, BMR LCAs, BMR toelinks, BMR trailing arms, BMR cradle bushings, BMR sway bars w/ endlinks, Vitesse paddles, heritage grille, and an eBay splitter
|06-04-2014, 09:31 AM||#3|
2010 2SS/RS M6
Drives: 2010 2SS/RS M6
Join Date: Jun 2010
Location: Castle Rock, CO
What about slotted rotors?
2/7/2014: 419 hp, 419 tq
Cosmetic: ZL1 front w/mailslot, painted stripes, powdercoated SS rims, tow hook, and Gary's customs bowties, painted emblems and taillight bezels, DIY Flowtie
Suspension: Pfadt subframe bushings, Pfadt rear UCA bushings, Spohn Trailing arms with del-sphere ends & BMR outer bushings, ZL1 Toe Rods and springs, Prothane radius arm inserts and steering rack bushing, Pfadt Sport sways & endlinks, Pfadt strut brace
Drivetrain: RMCR tune, CAI intake, Kooks headers, high-flow cats & exhaust, VMAX TB, LSR Tri-Ax shifter
Bumblebee Racecar Build
|06-04-2014, 11:27 AM||#4|
Drives: 2013 AGM 1SS/1LE
Join Date: Nov 2012
Location: Suburbs of Detroit, MI
AMEN......but sheeple will continue to spend money on parts that are not needed.
My 1LE Build/Journal : http://www.camaro5.com/forums/showthread.php?t=351990
|06-04-2014, 11:09 PM||#5|
Negative Camber Junkie
Drives: 2010 1SS LS3/6MN ABM 1 of 23
Join Date: May 2009
Location: ChiTown, IL
^^ Too True and telling them any different is like telling them the Easter Bunny died at the hands of Chim Chim.
"Horsepower is something that looks great in a Magazine article, but suspension is what actually gets you around the track fast.." Jack Olsen
The drag strip is like sniffing glue, it's cheap, it's a decent buzz, it doesn't last long and they are all the same.
Road racing is like China White Heroin, the buzz is stronger, the high lasts for hours, it's extremely addictive and they are all different.
I can't wait for my next Track fix. DA HAWKS used to OWN DA CUP!!!!!