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This is why its the year 2022 and: "This is why high end BMW, Porsche, Corvette, and Mercedes rotors are drilled."
Where I am I have lots of friends that own those cars, and I have in the past with the Drilled Rotors. They don't have a mass Rotor crack recall. Someone supplies, produces those Rotors for them. Guess who? This make Zero sense?
Physics wins. Every time. Rotors are merely large heat sinks. The rotors and wheels on those cars are cartoonishly oversized to the point that the average person can't heat them up. Slotted and drilled rotors are bling and a very minor weight reduction. That's why the make them from exotic carbon fiber in the top end examples. Porsche offers drilled/slotted rotors because people spending that much money think they need it.
The best brakes are the largest vented rotor you can fit to a vehicle without holes or slots in the contact surface, the thicker the better. Heavy isn't the greatest for racing but it excellent for braking.
NASCAR uses thicker vented rotors on short tracks and road courses. They use lighter rotors on superspeedways because the brakes are barely used, mostly for coming into the pits. You never brake in a high bank oval when actually racing and just let off the throttle.
Formula 1 rotors are flat with vents. They want maximum performance.
Finally, if slotting and drilling are so great, why aren't flywheels and pressure plates slotted or drilled? Two reasons: 1) Nobody can see them. 2) They need to hold a lot more power than the brakes.
Physics wins. Every time. Rotors are merely large heat sinks. The rotors and wheels on those cars are cartoonishly oversized to the point that the average person can't heat them up. Slotted and drilled rotors are bling and a very minor weight reduction. That's why the make them from exotic carbon fiber in the top end examples. Porsche offers drilled/slotted rotors because people spending that much money think they need it.
The best brakes are the largest vented rotor you can fit to a vehicle without holes or slots in the contact surface, the thicker the better. Heavy isn't the greatest for racing but it excellent for braking.
NASCAR uses thicker vented rotors on short tracks and road courses. They use lighter rotors on superspeedways because the brakes are barely used, mostly for coming into the pits. You never brake in a high bank oval when actually racing and just let off the throttle.
Formula 1 rotors are flat with vents. They want maximum performance.
Finally, if slotting and drilling are so great, why aren't flywheels and pressure plates slotted or drilled? Two reasons: 1) Nobody can see them. 2) They need to hold a lot more power than the brakes.
Are you trying to make a leap to comparing NASCAR and Formula 1 speeds and Race Car braking stress to our street cars being driven on the streets? I hope not.
Would you send this info you posted above to "high end BMW, Porsche, Corvette, and Mercedes rotors are drilled.", and tell them they got all their Engineering and data wrong because your home Garage knowledge says different? Or.... that cheap stuff can break.
I've been replacing my Stock Rotors with High Quality Drilled Rotors for 10 plus years all with 10's of thousands of other car Owners. Because of the internet myth not understanding chamfered drilled and high quality metal processes (Technology gets better) I have even had them https://www.motortrend.com/how-to/ct...le-inspection/ inpected. I have never had any cracks because I buy quality stuff not Ebay cheapo stuff. Neither does "high end BMW, Porsche, Corvette, and Mercedes rotors that are drilled."
I would be glad to entertain what you actually used in drilled Rotors and found? I could be wrong but it appears your decision is you have never had any experience with them at all. Due to you explanations and post here. I am Not saying Drilled Rotors ar Super brakes. I am saying everything you are unaware of and saying about this is all wrong.
Again you may want to read through these links below. Myself and them have some experience with them. Normally that helps with opinions on a topic. You have got to start understanding that Technology has gotten better and better over the years and its 2022
Alas anything can go bad. There are No lifetime car Brakes that I am aware of. Not yet anyway. But companies do use defects to improve products all the time. Cars have changed from Drum brakes and Carburetors, and having to lap and adjust Valves.
Here my my last post for FYI correcting incorrect info posted in this thread. The below Correct info is from a member of the SAE (Society of Automotive Engineers), who was able to copy ""The Effect of Rotor Cross Drilling on Brake Performance" by two GM engineers published in 2006."
It's more closely based on Street stopping and street Brake performance stress. Of course some internet posting non expert posted some negative comments on some site that had Zero experience and had no idea what they were talking about. Even posted irrelevant pics of cheap Rotors that were modified incorrectly with useless data that did not apply in spite of the GM Engineers test data. None below are any my statements.
Begin Quote: "For those that are interested in upgrading from a stock rotor to either drilled or slotted, read this from an engineer's stand point. I helped me make my decision to just get drilled rotors on all four corners. Thank..
There are many claims as to the benefits of drilled vs slotted rotors on stopping power. This guide is intended to provide some facts about drilled and slotted rotors. As a member of the SAE (Society of Automotive Engineers), I was pleased to see a paper "The Effect of Rotor Crossdrilling on Brake Performance" by two GM engineers published in 2006. They examined three vehicle platforms with cross-drilled rotors vs standard rotors to measure convection cooling capability, fade characteristics, wet braking, pedal feel and lining wear. The result is summarized as follows:
For the sports sedan, the coefficient of friction was 21% higher for drilled rotors than standard front rotors at 340F and higher using 15 brake snubs at 62mph. The track simulated 124 mph fade test showed 37% better brake output for drilled rotors. The drilled rotor brake temperature was about 150 degrees cooler.
For the performance car, the coefficient of friction was significantly higher for drilled rotors especially at high temperature.
Wet braking at high pedal pressure was the same for drilled or standard rotors. Wet braking is not significantly improved by drilled rotors.
Pedal force was much more consistent with drilled rotors over the brake temperature range. That is, to stop at the same deceleration rate, the driver does not need to modulate pedal pressure based on different brake temperatures. This reduces driver fatigue and improves brake response.
The authors also reported that drilled rotors prevent pad resin glazing on the rotor. So we now have solid evidence that drilled rotors have benefits over standard rotors. However, I have not found any published paper to show how slots affect brake output. So I reviewed inertial dynamometer tests using ISO NWI 26867 from Link Testing in Detroit with slotted rotors vs standard rotors. The results showed no significant difference in the coefficient of friction during the fade sections, hot stop section or pedal sensitivity portion of the test. My hypothesis is that slotted rotors do not contribute to rotor cooling whereas drilled rotors improve convection heat transfer to cool rotors and reduce brake fade. I should also point out that the pad lining wear for the slotted rotor was very severe during the test, i.e. the pad was chewed up over 20% more than the lining with stock rotors. While I believe that slots will help remove gas and debri from under the pad, I am not sure that this has a significant effect on brake torque for normal street driving. Perhaps the effect of slotted rotors is more significant on the race track, and conversely, I believe that drilled rotors are better for street and highway driving. For most drivers, I recommend drilled rotors over slotted rotors, and this conclusion is supported by the fact that Corvette, Ford GT, Porsche, Mercedes and BMW come with OEM drilled rotors.
Moving on to the original post topic of the LS 2 piston upgrade.
Here my my last post for FYI correcting incorrect info posted in this thread. The below Correct info is from a member of the SAE (Society of Automotive Engineers), who was able to copy ""The Effect of Rotor Cross Drilling on Brake Performance" by two GM engineers published in 2006."
It's more closely based on Street stopping and street Brake performance stress. Of course some internet posting non expert posted some negative comments on some site that had Zero experience and had no idea what they were talking about. Even posted irrelevant pics of cheap Rotors that were modified incorrectly with useless data that did not apply in spite of the GM Engineers test data. None below are any my statements.
Begin Quote: "For those that are interested in upgrading from a stock rotor to either drilled or slotted, read this from an engineer's stand point. I helped me make my decision to just get drilled rotors on all four corners. Thank..
There are many claims as to the benefits of drilled vs slotted rotors on stopping power. This guide is intended to provide some facts about drilled and slotted rotors. As a member of the SAE (Society of Automotive Engineers), I was pleased to see a paper "The Effect of Rotor Crossdrilling on Brake Performance" by two GM engineers published in 2006. They examined three vehicle platforms with cross-drilled rotors vs standard rotors to measure convection cooling capability, fade characteristics, wet braking, pedal feel and lining wear. The result is summarized as follows:
For the sports sedan, the coefficient of friction was 21% higher for drilled rotors than standard front rotors at 340F and higher using 15 brake snubs at 62mph. The track simulated 124 mph fade test showed 37% better brake output for drilled rotors. The drilled rotor brake temperature was about 150 degrees cooler.
For the performance car, the coefficient of friction was significantly higher for drilled rotors especially at high temperature.
Wet braking at high pedal pressure was the same for drilled or standard rotors. Wet braking is not significantly improved by drilled rotors.
Pedal force was much more consistent with drilled rotors over the brake temperature range. That is, to stop at the same deceleration rate, the driver does not need to modulate pedal pressure based on different brake temperatures. This reduces driver fatigue and improves brake response.
The authors also reported that drilled rotors prevent pad resin glazing on the rotor. So we now have solid evidence that drilled rotors have benefits over standard rotors. However, I have not found any published paper to show how slots affect brake output. So I reviewed inertial dynamometer tests using ISO NWI 26867 from Link Testing in Detroit with slotted rotors vs standard rotors. The results showed no significant difference in the coefficient of friction during the fade sections, hot stop section or pedal sensitivity portion of the test. My hypothesis is that slotted rotors do not contribute to rotor cooling whereas drilled rotors improve convection heat transfer to cool rotors and reduce brake fade. I should also point out that the pad lining wear for the slotted rotor was very severe during the test, i.e. the pad was chewed up over 20% more than the lining with stock rotors. While I believe that slots will help remove gas and debri from under the pad, I am not sure that this has a significant effect on brake torque for normal street driving. Perhaps the effect of slotted rotors is more significant on the race track, and conversely, I believe that drilled rotors are better for street and highway driving. For most drivers, I recommend drilled rotors over slotted rotors, and this conclusion is supported by the fact that Corvette, Ford GT, Porsche, Mercedes and BMW come with OEM drilled rotors.
Moving on to the original post topic of the LS 2 piston upgrade.
Then why are the TRUE performance rotors solid? Answer me that. F1 and NASCAR really want to stop and NO expense is spared in their efforts. TRUE performance doesn't care about looks. That is also why flywheels and pressure plates are big, thick and solid.
Drag cars use slotted and/or drilled rotors, often non-vented because they only have to stop once an hour at the end of the track. Any saved weight is a quicker ET. They use soft pads that instantly bite and who cares if they last more than a season. About the only thing not as light as possible is the roll cage.
Then why are the TRUE performance rotors solid? Answer me that. F1 and NASCAR really want to stop and NO expense is spared in their efforts. TRUE performance doesn't care about looks. That is also why flywheels and pressure plates are big, thick and solid.
Drag cars use slotted and/or drilled rotors, often non-vented because they only have to stop once an hour at the end of the track. Any saved weight is a quicker ET. They use soft pads that instantly bite and who cares if they last more than a season. About the only thing not as light as possible is the roll cage.
KB, this is the 2nd post that you are asking me why this, why that, then why? Your original statement was that slotted Rotors would be no help, in a 4th Gen GS thread where we were talking about 4th Gen GS brake upgrades and changes. I don't know why in the hell you tuned this into a NASCAR & F1 cars topic? Now you are talking about Drag cars? You may be right about Race cars, but that Ain't what we are talking about here, now is it? Its a nice spin for the Fact that Slotted Rotors do perform well and better on Sport Sedan Street cars, and this... again:
"For those that are interested in upgrading from a stock rotor to either drilled or slotted, read this from an engineer's stand point. I helped me make my decision to just get drilled rotors on all four corners. Thank..
There are many claims as to the benefits of drilled vs slotted rotors on stopping power. This guide is intended to provide some facts about drilled and slotted rotors. As a member of the SAE (Society of Automotive Engineers), I was pleased to see a paper "The Effect of Rotor Crossdrilling on Brake Performance" by two GM engineers published in 2006. They examined three vehicle platforms with cross-drilled rotors vs standard rotors to measure convection cooling capability, fade characteristics, wet braking, pedal feel and lining wear. The result is summarized as follows:
For the sports sedan, the coefficient of friction was 21% higher for drilled rotors than standard front rotors at 340F and higher using 15 brake snubs at 62mph. The track simulated 124 mph fade test showed 37% better brake output for drilled rotors. The drilled rotor brake temperature was about 150 degrees cooler.
Is the 4th Gen GS a Sport Sedan street car? Or a NASCR, F1, Drag car? Dude those cars brake have to last a whole high speed excessive braking Race. Also how much does your posted pic F1 car weight = only 1900lbs. They also don't normally use them again. You are moving the goal post. lol!
A better Street Car pic for you! What does the 303mph car Manufacture know?
The best brakes for a street car are solid, vented rotors of the largest diameter that will fit. Period. Anything else is cosmetic. Everything that was once exclusively race tech trickles down to the rest of the auto industry. Cars used to be 4 wheel drums and discs first appeared on race cars. Overhead cams used to be rare and now about every Toyota is overhead cam. 4 valves per cylinder was pioneered in racing but now quite common. What works on the track improves what's on the street.
People that sell slotted and drilled rotors will always say they are better despite the removal of metal, shorter life span and higher likelihood of cracks than flat faced rotors.
The best brakes for a street car are solid, vented rotors of the largest diameter that will fit. Period. Anything else is cosmetic. Everything that was once exclusively race tech trickles down to the rest of the auto industry. Cars used to be 4 wheel drums and discs first appeared on race cars. Overhead cams used to be rare and now about every Toyota is overhead cam. 4 valves per cylinder was pioneered in racing but now quite common. What works on the track improves what's on the street.
People that sell slotted and drilled rotors will always say they are better despite the removal of metal, shorter life span and higher likelihood of cracks than flat faced rotors.
All rotors being the same size, pads will make a greater difference than anything besides tires.
Those "Porsche used blank rotors with this" are......... Tungsten Carbide Rotors. Whole different thing now. Not sure where you are going with this one?
02-19-22, 09:02 PM
Now you are talking about Drag cars? You may be right about Race cars, but that Ain't what we are talking about here, now is it? Its a nice spin for the Fact that Slotted Rotors do perform well and better on Sport Sedan Street cars, and this... again:
