mjones73
New Member
I see that now, if you need those for street driving, I'd expect you'd put the money into the proper supporting rotors to go with them.
Rotors
- Thread starter Afireinside
- Start date
Afireinside
New Member
Please elaborate on this if you dont mind?
mirrorimg
Well-Known Member
One question...
How?
Not trying to get into a highschool debate match here... but being an ASE certified mechanic i would like to hear the technical explanation behind this~
I could see if it were some upgraded friction material that made the rotors heat up to excess... that would cause warpage.... but not just regular braking... or the material itself...
I'll give my perspective on the racing pads/daily drivers.
Daily driving = long, drawn out braking until a complete stop, in which you constantly have your foot on the pedal. Your brakes will heat up and when you come to a complete stop, the pad will sit on the rotor and not give it time to cool down. There is also no air flow across the rotor to keep it cool because: A. you dont have air ducts and B. the car is not moving. The rotor will cool somewhat on the opposite side, while the pad section retains its heat. I believe this unevenness is what causes the warpage.
In a track session, there is constant air, you brake, then let off and the rotors cool again (to an extent). You never have the pad sitting in one location holding in heat as a different side of the rotor cools. This way the rotor is equally hot around the circumference of the rotor and does not have hot/cooler spots.
Afireinside
New Member
Anyone?
Cman46290
New Member
Yeah...
basically... after installing new rotors.... or even putting the rotors back on after machining them and doing front pads....
If you dont install the wheel to proper torque specs in the proper "Star" or "Criss cross" pattern then you take the chanc or warping the rotor.
When i put a wheel on after doing a brake job... i will tighten every kug nut snug down finger tight.... while still in the air... then take my 19mm and torque wrench and tighten them as much as i can while still up in the air... just to make sure the wheel is snug and flush against the hub...
Then i will lower it just enough for the tires to contact the ground with enough pressure that the wheel wont turn when i tighten the lugs.... and ill start on one lug... toghten to 80lbs... then go to the one across from it... tighten it 80lbs... so on and so forth.
thats the proper way... and its not overtorqueing the lugs....
No ive seen idiots just throw one lug on... and use an impact at 150lbs pressure just tighten the one all the way down.... then the one right next to it.... and just go around in a circle... while continuously overtorquing the lugs... and not doing the star pattern tighten method... and completely warp the fuck out of the rotor.
-Corey
Afireinside
New Member
I see I figured everyone did it that way! Thanks
tjberry_1
Autocrosser
I dont think you quite have this right...
Pads:
Track-oriented pads dont make a ton of heat just because they're a track pad. In fact, its not about "making" heat at all... its about operating temp. Track-oriented pads require more heat than a street pad to get up to optimum operating temp. Research the specs on pads and you'll see that the more extreme the track-pad, the higher its required operating temp range. This is why they're not recommended (and even dangerous) on the street... you just wont get the track pads up to the proper operating temp on the street to make them useful... and when pads arent up to their operating temp, they dont generate as much friction. Conversely, street pads are terrible on the track because they overheat; their operating temp is quickly exceeded by brake temps seen on-track. When they're overheated, they get slippery or even crack and crumble.
Rotors:
Also slotted/cross-drilled vs. blank rotors is one of the most asked questions on every forum I've been on and its amazing how much mis-information is spread.
Cross-drilled or slotted rotor DO NOT improve your braking in dry conditions for two reasons:
1) They DO NOT dissipate more heat. Heat in a rotor is dissipated via the rotos's mass. By slotting or cross-drilling, there is less mass to dissipate heat into.
2) Friction is what stops you. Maximize friction and you maximize braking. Friction is created when the surface of the pad contacts the surface of the rotor. When you cross-drill or slot a rotor, you've just reduced the surface area of the rotor. By reducing the surface area, you've reduced the friction. By reducing the friction, you've reduced your braking performance.
Other than looks, the only benefit to slotting is possibly in the wet. The slot will basically be constantly cleaning the water off the pad during braking, so your wet braking performance may be better than without slots.
There is no real benefit to cross-drilling other than looks. Cross-drilled rotors are prone to cracking unless they are cast into the rotor, and only higher-end cars have these. Higher-end cars have them because people expect :high-performance" rotors on a higher-end car, and "high-performance" rotors are drilled and slotted right? :roll: And lets be honest... most high end cars are not tracked. Go to any NASA or SCCA track day and see what 99% of real racers run.... you wont see many drilled/slotted rotors... you'll see lots and lots of blanks.
Cman46290
New Member
I think you missed the WHOLE point of this thread. The debate was why/how rotors warp. And the fact is rotors warp MAINLY due to heat... or overheating...
not because of certain pad.... or rotor.
Obviously you can buy cheap ass rotors that will warp easier than a quality rotor... and same with the pads and how they wear.. and how fast... how much brake dust they give off and heat... ect ect....
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Cman46290
New Member
This is right from the website "HOW STUFF WORKS.COM"
http://auto.howstuffworks.com/auto-parts/brakes/brake-parts/brake-rotors2.htm
SLOTTED BRAKE ROTORS
"Slotted brake rotors use slots carved into the flat metal surface
to move gas, heat and water away from the surface of the rotors.
You can think of the slots as irrigation ditches that move the unwanted materials safely out of the way."
And furthermore....
http://auto.howstuffworks.com/auto-parts/brakes/brake-parts/brake-rotors1.htm
DRILLER BRAKE ROTORS
"There are two major types of high-performance brake rotors -- drilled and slotted. We'll discuss the drilled rotors here and move on to the slotted rotors on the next page. Drilled brake rotors, as the name implies, have holes drilled in them. Having a holes drilled into any of your brake parts may seem counterintuitive, especially the brake rotors -- after all, a rotor full of holes means that there's less surface area for the brake pads to grab and stop the car -- but there are a few reasons drilled rotors make sense.
The first is heat. When the brake pad grabs the rotor, it creates friction, which creates heat. If that heat can't escape, it leads to brake fade, which reduces the brakes' stopping power. The second reason is gas build up. This actually isn't much of a problem any more; however, the materials used in some older types of brake pads caused gas to build up between the rotors and pads. That gas also limited stopping power. The last reason is water. If a car drives through a puddle, a carwash or even a rainstorm, the brake rotors can get wet."
SO id say you may want to check your info about slotted or drilled rotors... and them not being able to dissipate heat... especially before trying to point and tell someone they are wrong in their theory. Thanks.
-Corey
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mirrorimg
Well-Known Member
You must have missed the section to where he stated high performance pads need that higher temperature to grab like they should. So you wont see any brake fade (unless your brake fluid cant stand up to the temps) in track scenarios.
Yes we are talking about rotors, but this probably shouldnt have been bolded.
Cman46290
New Member
Right.. i understand you DONT want to lose heat on "RACING" brake pads.... and you need them to get hot to work properly... thats understood... and im not debating that... at all...
But he also said that drilled and slotted rotors "DONT DISSIPATE MORE HEAT"
Thats where he was off.
tjberry_1
Autocrosser
I understood the point of the thread. My reply was because you told him the rotors are warping because his track pads are creating too much heat, so the rotors arent the right ones for his pads. This is just wrong and its clear you have the same understanding of how brakes work as the rotor-salesmen want you to have.
Couple problems in your "evidence"...
1) Gasses? What gasses. Another myth. Modern brake pads dont release gasses. Do more research.
2) How will slots move heat away from a rotor? Its not like they create a little fanning effect lol. The heat escapes INTO the rotor. The rotor is a heat sink, which is why bigger rotors are better, but do not necessarily make you immediately stop better... they resist fade better because they can hold more heat. Add to that, that front rotors are already vented, which is a vaned cooling path and IS essentially a little fan that slots cannot hold a candle to.
But ok. You can get your racing engineering info from HowStuffWorks.com (really? thats really going to be your source for this information??). I'll get mine from experience, my knowledge of thermodynamics and heat transfer, and actual real-life racers.
Not as "official" :roll: as howstuffworks, but lots of actual experience from all over the automotive world agrees:
http://www.marcusfitzhugh.com/CLK/DIY/brakecdrill.html
http://www.g20.net/forum/showthread.php?t=91131
http://www.corner-carvers.com/forums/showthread.php?t=2002&highlight=cross+drilled+rotors
http://www.honda-tech.com/showthread.php?t=1437513
http://www.honda-tech.com/showthread.php?t=2382409
http://www.team-integra.net/forum/display_topic_threads.asp?ForumID=14&TopicID=47358&PageMsg=Viewing+Common+Topic
http://forums.bimmerforums.com/forum/showthread.php?t=1458626
http://www.rx8club.com/showthread.php?t=84552
...and on and on...
Couple problems in your "evidence"...
1) Gasses? What gasses. Another myth. Modern brake pads dont release gasses. Do more research.
2) How will slots move heat away from a rotor? Its not like they create a little fanning effect lol. The heat escapes INTO the rotor. The rotor is a heat sink, which is why bigger rotors are better, but do not necessarily make you immediately stop better... they resist fade better because they can hold more heat. Add to that, that front rotors are already vented, which is a vaned cooling path and IS essentially a little fan that slots cannot hold a candle to.
But ok. You can get your racing engineering info from HowStuffWorks.com (really? thats really going to be your source for this information??). I'll get mine from experience, my knowledge of thermodynamics and heat transfer, and actual real-life racers.
Not as "official" :roll: as howstuffworks, but lots of actual experience from all over the automotive world agrees:
http://www.marcusfitzhugh.com/CLK/DIY/brakecdrill.html
http://www.g20.net/forum/showthread.php?t=91131
http://www.corner-carvers.com/forums/showthread.php?t=2002&highlight=cross+drilled+rotors
http://www.honda-tech.com/showthread.php?t=1437513
http://www.honda-tech.com/showthread.php?t=2382409
http://www.team-integra.net/forum/display_topic_threads.asp?ForumID=14&TopicID=47358&PageMsg=Viewing+Common+Topic
http://forums.bimmerforums.com/forum/showthread.php?t=1458626
http://www.rx8club.com/showthread.php?t=84552
...and on and on...
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Cman46290
New Member
Sigh... there is no point in arguing here... this could go on forever... wasting my time.
I could care less about high speed racing application when it comes to brakes... because its irrelevant to the normal person whom does regular daily driving.
The moral to this - I dont have nor do i use cross drilled or slotted rotors....
The gain from those is useless on a daily driving application... and they are quite frankly a waste of money.
Done deal.
Im done. :thumbs up