slotted? drilled? oem? Rotors.
#1
Join Date: Apr 2008
Location: Holmdel, NJ --Exit 114
Posts: 4,235
slotted? drilled? oem? Rotors.
What's the difference between slotted and drilled rotors? I was looking at Brembo and their lineup is:
slotted $208
drilled $194
OEM $46
per rotor.
Why is slotted more expensive than drilled?
slotted $208
drilled $194
OEM $46
per rotor.
Why is slotted more expensive than drilled?
#7
Drilled: Race
Slotted: Possibly Auto-X/Hard driving
Blanks (OEM): Street
I don't recommend the drilled for anything other than a race application, they tend to crack between the drilled holes after awhile. the holes allow faster cooling. when the brakes are used, a layer of gas is formed between the rotor and the brake pad (with certain brake pad compounds), the holes can act as an escape for the gas.
slotted rotors are stronger than drilled, and have grooves for the gas to escape and aid in cooling a bit.
a down side to both of these rotors is that there is less over-all surface area of pad-to-rotor contact reducing the amount of friction/effectiveness of the brakes when paired with an OEM caliper. so unless you do hard driving/braking or autocross, i would recommend the blank style rotor. brembo designs great cooling vents inside the rotor which aid in cooling more than OEMs.
Slotted: Possibly Auto-X/Hard driving
Blanks (OEM): Street
I don't recommend the drilled for anything other than a race application, they tend to crack between the drilled holes after awhile. the holes allow faster cooling. when the brakes are used, a layer of gas is formed between the rotor and the brake pad (with certain brake pad compounds), the holes can act as an escape for the gas.
slotted rotors are stronger than drilled, and have grooves for the gas to escape and aid in cooling a bit.
a down side to both of these rotors is that there is less over-all surface area of pad-to-rotor contact reducing the amount of friction/effectiveness of the brakes when paired with an OEM caliper. so unless you do hard driving/braking or autocross, i would recommend the blank style rotor. brembo designs great cooling vents inside the rotor which aid in cooling more than OEMs.
#9
you dont need slotted or drilled rotors for driving around on the street,
the thing is your oem brakes are more than capable of locking the wheels, but the abs will come on, if you get sticky enough tires, and your brakes are no longer able to lock, (abs), then you could think about a better braking system,....if you need that kind of stopping power, which i cant imagine anyone really does
your brakes are only as good at your tires.
although slotted or drilled rotors do look good
the thing is your oem brakes are more than capable of locking the wheels, but the abs will come on, if you get sticky enough tires, and your brakes are no longer able to lock, (abs), then you could think about a better braking system,....if you need that kind of stopping power, which i cant imagine anyone really does
your brakes are only as good at your tires.
although slotted or drilled rotors do look good
#11
you dont need slotted or drilled rotors for driving around on the street,
the thing is your oem brakes are more than capable of locking the wheels, but the abs will come on, if you get sticky enough tires, and your brakes are no longer able to lock, (abs), then you could think about a better braking system,....if you need that kind of stopping power, which i cant imagine anyone really does
your brakes are only as good at your tires.
although slotted or drilled rotors do look good
the thing is your oem brakes are more than capable of locking the wheels, but the abs will come on, if you get sticky enough tires, and your brakes are no longer able to lock, (abs), then you could think about a better braking system,....if you need that kind of stopping power, which i cant imagine anyone really does
your brakes are only as good at your tires.
although slotted or drilled rotors do look good
do u really need to bench press your own weight?
do u really need straight A's?
do u really need to shower and brush your teeth everyday?
do u really need a million dollars?
do u really need a lingerie model to give u a bj in the morning everyday?
ever wonder why having upgraded brakes gives u no penalty points in racing?
BRAKES (that's including the most important part of the braking system ..THE TIRES) are arguably THE most important thing in a car
Last edited by SFactor2; 12-21-2008 at 06:27 PM.
#12
(FYI I didn't write this, I lifted it from another forum, it's from a guy from Stoptech)
Let’s look at some common rotor ‘modification’ and ‘performance’ upgrades that you may have been exposed to and try to separate the marketing from the engineering…
Super Sizing
Bigger rotors will make your friends think you are cool, bigger rotors look sexy, but bigger rotors do not stop the car. What a bigger rotor will do is lower the overall operating temperature of the brakes – which is a GREAT idea IF your temperatures are causing problems with other parts of the braking system. Take for example a F500 racecar – a small 800 pound single seat formula car. While the brakes are certainly much smaller than those found on a 3,000 pound GT1 Camaro, that does not necessarily mean that they need to be made larger. In fact, swapping on a GT1 brake package would probably do more harm than good – that’s a lot of steel hanging on the wheel that needs to accelerate each time the ‘go’ pedal is pushed. So, the motto of this story is bigger is better until your temperatures are under control. After that point, you are doing more harm than good…unless you really like the look (and hey – some of us do!).
Crossdrilling
Crossdrilling your rotors might look neat, but what is it really doing for you? Well, unless your car is using brake pads from the 40’s and 50’s, 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’. These gasses then formed a thin layer between the brake pad face and the rotor, acting as a lubricant and effectively lowering the coefficient of friction. The holes were implemented to give the gasses ‘somewhere to go’. It was an effective solution, but today’s friction materials do not exhibit the same gassing out phenomenon as the early pads.
For this reason, the holes have carried over more as a design feature than a performance feature. Contrary to popular belief they don’t lower temperatures (in fact, by removing weight from the rotor, the temperatures can actually increase a little), they create stress risers allowing 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.)
The one glaring exception here is in the rare situation where the rotors are so oversized (look at any performance motorcycle or lighter formula car) that the rotors are drilled like Swiss cheese. While the issues of stress risers and brake pad wear are still present, drilling is used to reduce the mass of the parts in spite of these concerns. Remember – nothing comes for free. If these teams switched to non-drilled rotors, they would see lower operating temperatures and longer brake pad life – at the expense of higher weight. It’s all about trade-offs.
Slotting
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?)
Too cool!
Last year we bought 4 rotors. Two were bone stock, and two were subjected to a process know as Cryogenically Treating – one of the high-tech buzzwords floating around the paddock. The rotors were run back-to-back on the same track on the same car on the same day with temperatures taken to make sure that they saw the same level of heat. Following the track session, the parts were removed and we had them literally dissected by a materials lab.
The testing conducted included surface hardness, grain structure analysis, density, and surface scanning with an electron microscope. Guess what – after seeing the heat of use, the rotors looked identical in every regard. This is not to say that there is not a benefit from treating other parts which see lower temperatures and/or have different material properties, but treating our rotors on our car showed no tangible benefits (note that it didn’t seem to hurt anything either). Come to your own conclusions, but in our case, we’ll pass.
Summary
So, what’s the secret recipe? Again, there is no absolute right or wrong answer, but like most modifications, there are those which appear to be well-founded and those that ‘look cool.’ If ultimate thermal performance is your goal, look to what the top teams are running (relatively large, slotted rotors). However, if ‘image’ is your thing, break out the drillpress – and be prepared to replace your brake pads on a regular basis
Let’s look at some common rotor ‘modification’ and ‘performance’ upgrades that you may have been exposed to and try to separate the marketing from the engineering…
Super Sizing
Bigger rotors will make your friends think you are cool, bigger rotors look sexy, but bigger rotors do not stop the car. What a bigger rotor will do is lower the overall operating temperature of the brakes – which is a GREAT idea IF your temperatures are causing problems with other parts of the braking system. Take for example a F500 racecar – a small 800 pound single seat formula car. While the brakes are certainly much smaller than those found on a 3,000 pound GT1 Camaro, that does not necessarily mean that they need to be made larger. In fact, swapping on a GT1 brake package would probably do more harm than good – that’s a lot of steel hanging on the wheel that needs to accelerate each time the ‘go’ pedal is pushed. So, the motto of this story is bigger is better until your temperatures are under control. After that point, you are doing more harm than good…unless you really like the look (and hey – some of us do!).
Crossdrilling
Crossdrilling your rotors might look neat, but what is it really doing for you? Well, unless your car is using brake pads from the 40’s and 50’s, 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’. These gasses then formed a thin layer between the brake pad face and the rotor, acting as a lubricant and effectively lowering the coefficient of friction. The holes were implemented to give the gasses ‘somewhere to go’. It was an effective solution, but today’s friction materials do not exhibit the same gassing out phenomenon as the early pads.
For this reason, the holes have carried over more as a design feature than a performance feature. Contrary to popular belief they don’t lower temperatures (in fact, by removing weight from the rotor, the temperatures can actually increase a little), they create stress risers allowing 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.)
The one glaring exception here is in the rare situation where the rotors are so oversized (look at any performance motorcycle or lighter formula car) that the rotors are drilled like Swiss cheese. While the issues of stress risers and brake pad wear are still present, drilling is used to reduce the mass of the parts in spite of these concerns. Remember – nothing comes for free. If these teams switched to non-drilled rotors, they would see lower operating temperatures and longer brake pad life – at the expense of higher weight. It’s all about trade-offs.
Slotting
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?)
Too cool!
Last year we bought 4 rotors. Two were bone stock, and two were subjected to a process know as Cryogenically Treating – one of the high-tech buzzwords floating around the paddock. The rotors were run back-to-back on the same track on the same car on the same day with temperatures taken to make sure that they saw the same level of heat. Following the track session, the parts were removed and we had them literally dissected by a materials lab.
The testing conducted included surface hardness, grain structure analysis, density, and surface scanning with an electron microscope. Guess what – after seeing the heat of use, the rotors looked identical in every regard. This is not to say that there is not a benefit from treating other parts which see lower temperatures and/or have different material properties, but treating our rotors on our car showed no tangible benefits (note that it didn’t seem to hurt anything either). Come to your own conclusions, but in our case, we’ll pass.
Summary
So, what’s the secret recipe? Again, there is no absolute right or wrong answer, but like most modifications, there are those which appear to be well-founded and those that ‘look cool.’ If ultimate thermal performance is your goal, look to what the top teams are running (relatively large, slotted rotors). However, if ‘image’ is your thing, break out the drillpress – and be prepared to replace your brake pads on a regular basis
#13
and fwiw, I agree slotted is still better (for our race application anyway)as in the post above, the slots can effectively scrape off the brake pads, cleaning off the surface with every revolution. We use brembo slotted (& vented) rotors on our FG2 & FA5 touring cars, it's actually a NASCAR rear rotor.
looks something like this:
But if it was me, for a street car, I'd just buy Brembo blanks!
looks something like this:
But if it was me, for a street car, I'd just buy Brembo blanks!
#14
if you want REAL stopping power, you need sticky tires and carbon composite blank rotors and metallic pads. only use metallic pads and composite rotors if you live somewhere that has warm weather all year round because the coefficient of friction span is very small on metallic pads so they need to be run hot at all times in order for them to work, sooo the best place for them would be the track :P i agree with the others above that say for street use your best bet would be stickier compound tires. and yes better brakes are a very very good thing but you don't need to spend alot on brake systems to get ample stopping power, usually vented rotors and a semi-metallic of a composite brake pad will do the trick and they are within reach of your pocket!
#15
This guy knows his stuff
Drilled: Race
Slotted: Possibly Auto-X/Hard driving
Blanks (OEM): Street
I don't recommend the drilled for anything other than a race application, they tend to crack between the drilled holes after awhile. the holes allow faster cooling. when the brakes are used, a layer of gas is formed between the rotor and the brake pad (with certain brake pad compounds), the holes can act as an escape for the gas.
slotted rotors are stronger than drilled, and have grooves for the gas to escape and aid in cooling a bit.
a down side to both of these rotors is that there is less over-all surface area of pad-to-rotor contact reducing the amount of friction/effectiveness of the brakes when paired with an OEM caliper. so unless you do hard driving/braking or autocross, i would recommend the blank style rotor. brembo designs great cooling vents inside the rotor which aid in cooling more than OEMs.
Slotted: Possibly Auto-X/Hard driving
Blanks (OEM): Street
I don't recommend the drilled for anything other than a race application, they tend to crack between the drilled holes after awhile. the holes allow faster cooling. when the brakes are used, a layer of gas is formed between the rotor and the brake pad (with certain brake pad compounds), the holes can act as an escape for the gas.
slotted rotors are stronger than drilled, and have grooves for the gas to escape and aid in cooling a bit.
a down side to both of these rotors is that there is less over-all surface area of pad-to-rotor contact reducing the amount of friction/effectiveness of the brakes when paired with an OEM caliper. so unless you do hard driving/braking or autocross, i would recommend the blank style rotor. brembo designs great cooling vents inside the rotor which aid in cooling more than OEMs.
here is the brembo (non drilled/non slotted) blank part number for the 07-08 fit, you can pick these up at any CARQUEST auto parts store -- N1000-55256 BRE (might be special order)
I USE the same probuct on my 90 CRX track day (well the crx part number) and it's an awesome part
Last edited by vtecfit1; 01-30-2009 at 06:17 PM.
#16
Yes slotted are the best its what came stock on my old evo. I want to up grad the brake system to brembo calipers and rotors but than agian i remember that just brembo pads for my evo ran me at $450. But that will be my next mod is better stoping power
#17
WELL SAID !!!!!!!!!
here is the brembo (non drilled/non slotted) blank part number for the 07-08 fit, you can pick these up at any CARQUEST auto parts store -- N1000-55256 BRE (might be special order)
I USE the same probuct on my 90 CRX track day (well the crx part number) and it's an awesome part
here is the brembo (non drilled/non slotted) blank part number for the 07-08 fit, you can pick these up at any CARQUEST auto parts store -- N1000-55256 BRE (might be special order)
I USE the same probuct on my 90 CRX track day (well the crx part number) and it's an awesome part
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