Ordering my brakes today! Few last minute questions..

[jrgoffin]

Without getting into the debate over plain vs. drilled/slotted, the OP could have done a quick search and found numerous threads here lately on brakes.

If you didn't want to spend a ton of cash on the Baer rotors, you could have gone to rotorpros.com and picked up a drilled/slotted set (or whatever your preference is), which are Centric rotors, for less than $200 shipped...

Again, many threads lately, here's just a couple:

http://www.svtperformance.com/forums/suspension-modifications-211/312004-brake-rotor-question.html

http://www.svtperformance.com/forums/suspension-modifications-211/756563-brake-rotors-pads.html

 

[LargeOrangeFont]

The point there, GENIUS, was that if blanks produced comparable performance THOSE cars, which LIVE AND DIE by their performance, would be using blanks. You obviously didn't make the connection, so I'm connecting the dots for you.

:lol1:

As I said, those are RACE cars and create enough heat in the brakes that they can benefit from slots or holes in the rotors. They also use pads of a different composition and rotors that are thicker and more robust.

You are comparing apples to oranges, and still have not provided any evidence that they perform better on a passenger car. I have provided evidence that they do fail, and you can find many other instances of failure from other members that open track their cars.

 

[Taz]

As I said, those are RACE cars and create enough heat in the brakes that they can benefit from slots or holes in the rotors. They also use pads of a different composition and rotors that are thicker and more robust.

You are comparing apples to oranges, and still have not provided any evidence that they perform better on a passenger car. I have provided evidence that they do fail, and you can find many other instances of failure from other members that open track their cars.

Hahahahahahahahaahahahahaha!!!!

1. The fact of the matter is that more friction equates to shorter stopping distances, REGARDLESS of temperatures. Note that the title of the SAE report cited above is "The Effect of Rotor Crossdrilling on Brake Performance" 'Nuff said.

2. ALL better brake manufacturers compensate for the removal of material. That's what makes them BETTER brake companies and separates them from the garbage manufacturers who just drill standard blanks and sell them.

Why don't you demonstrate that you have enough brains to quit while you're behind?

You ever see the film Monty Python and the Holy Grail?

If so, do you remember the scene where King Arthur comes upon a bridge guarded by the Black Knight?

If so, then you probably remember that after some swordplay, the Black Knight is lying on the ground with no arms or legs claiming, "It's just a flesh wound."

You, sir, are that Black Knight.

Now, go away, boy, you bother me.

 

[LargeOrangeFont]

You actually need to read the WHOLE paper. I actually have it.. It is geared toward OEM style braking systems, not systems that are oriented for track use on a passenger car. There is no actual performance numbers given in the paper, and that is by design. There are only differences in temperatures, and friction noted. These factors will relate to consistency, and repeatability and feel.

One of the considerations in the paper is that they used semi-metallic brake pads (generally medium performance street pads) for all the testing. These typically have a max operating temp rating of about 500~550 deg C. Also the primary functional mechanism of this type of pad is abrasion rather than adhesion. By contrast, the higher temp rated race type pads are more biased towards an adhesive mechanism relying upon a transfer layer of material deposited on the rotor.

Where this comes in to play is in interpreting the test data that shows higher apparent friction and deceleration gain for the plain rotor at low temp, the cross-drilled rotor at higher temp, and generally greater temperature fade stability for the cross-drilled. At low temp, the greater surface area of the plain rotor is the dominant performance factor, as one would expect. At higher temps however, the breakdown of the pad is the dominant consideration and the cheese grater effect of the cross-drilled rotors helps to compensate for this by providing increased mechanical friction.

If however, this test were to be repeated with a higher temp rated adhesive type race pad, I'd expect the results to be exactly the opposite. That is at lower temps where you would expect the race pad to perform poorly, the cross-drilled rotors would provide an abrasive mechanism and increased performance. But at higher temps, not only would the lesser surface area of the cross-drilled rotor become the dominant consideration, but the abrasive mechanism of the holes would inhibit proper formation of the transfer layer.

Another interesting aspect is the wide base performance difference between the three brake systems used in the test. "System 3" appears to be an overall poor performer in comparison with the other 2 systems. In the case of System 3, the cross drilling appears to be a pure bling change, as it is rather consistently outperformed by the plain rotors, despite their being smaller in overall diameter. System 1 was a better performer, but quite unbalanced. Almost all the work on this system was being done by the front rotors. System 2 looks to be the best of the lot, and consequently showed the least radical performance deviations between the plain and cross-drilled rotors.

The base performance difference between System 1 and System 2 helps in interpreting the results showing increased cooling efficiency with the cross-drilled rotors. On System 1, tests at 50kph, 100kph, and 160kph, showed an increase of cooling values (hA) of 8.8%, 12.1%, and 20.1% on the front and -3.2%, 1.9%, and 8.5% on the rear. For System 2, the values at 50kph, 110kph, and 140kph are 7.8%, 10.4%, and 12.1% for the front and 4.1%, 7.7%, and 13.4% rear. The other key piece of data is the raw hA numbers. At 160kph, the average hA for the front rotors of System 1 is 19.26 for the plain rotors and 23.13 for the cross-drilled. By comparison, the System 2 values at 140kph are 23.35 for the plain rotors and 26.18 for the drilled. While cross-drilling does improve the cooling rate, the degree of benefit is inversely proportional to the size of the rotor. From a pure cooling rate consideration, the plain rotors of System 2 outperform the cross-drilled rotors of System 1. Using cross-drilled rotors would seem to make the most sense only after you have run out of options for increasing the rotor diameter.

Pad wear on cross-drilled rotors was also shown to be up to up to 50% greater under hard use, and about 25~30% greater under street use. What was not explicitly tested was the effect of this increased wear on temperature because the thinner the pad, the higher the pad temp. My suspicion is that at some point, the diminished heat capacity of the pad due to wear more than offsets the gain in cooling capacity of the cross-drilled rotors. This is one reason behind many of the catastrophic failures of cross-drilled rotors at the track. Basically, they will start off strong, but the accelerated rate of pad wear soon drives the rotor into an overheated condition.

Some of the other data and conclusions from the paper on cross-drilled rotors:
• There is no practical difference in wet weather performance.
• Pad outgassing is not factor
• Thermal fatigue life is significantly shorter for cross-drilled rotors. In the case of poorly balanced and possibly under-sized System 1, by as much as 50%.
• Drilled rotors do run cooler in certain conditions
• Pad wear with drilled rotors can be a concern


Taking all of that into consideration, there is no real compelling performance reason to use drilled rotors on car you plan on taking to the track. When you factor in that that rotors will fail sooner and eat pads quicker, I don’t know why you would use them at all for any kind of passenger car performance application.

 

[Taz]

You actually need to read the WHOLE paper. I actually have it.. It is geared toward OEM style braking systems, not systems that are oriented for track use on a passenger car.

One of the considerations in the paper is that they used semi-metallic brake pads (low performance street pads) for all the testing. These typically have a max operating temp rating of about 500~550 deg C. Also the primary functional mechanism of this type of pad is abrasion rather than adhesion. By contrast, the higher temp rated race type pads are more biased towards an adhesive mechanism relying upon a transfer layer of material deposited on the rotor.

Where this comes in to play is in interpreting the test data that shows higher apparent friction and deceleration gain for the plain rotor at low temp, the cross-drilled rotor at higher temp, and generally greater temperature fade stability for the cross-drilled. At low temp, the greater surface area of the plain rotor is the dominant performance factor, as one would expect. At higher temps however, the breakdown of the pad is the dominant consideration and the cheese grater effect of the cross-drilled rotors helps to compensate for this by providing increased mechanical friction.

If however, this test were to be repeated with a higher temp rated adhesive type race pad, I'd expect the results to be exactly the opposite. That is at lower temps where you would expect the race pad to perform poorly, the cross-drilled rotors would provide an abrasive mechanism and increased performance. But at higher temps, not only would the lesser surface area of the cross-drilled rotor become the dominant consideration, but the abrasive mechanism of the holes would inhibit proper formation of the transfer layer.

Another interesting aspect is the wide base performance difference between the three brake systems used in the test. "System 3" appears to be an overall poor performer in comparison with the other 2 systems. In the case of System 3, the cross drilling appears to be a pure bling change, as it is rather consistently outperformed by the plain rotors, despite their being smaller in overall diameter. System 1 was a better performer, but quite unbalanced. Almost all the work on this system was being done by the front rotors. System 2 looks to be the best of the lot, and consequently showed the least radical performance deviations between the plain and cross-drilled rotors.

The base performance difference between System 1 and System 2 helps in interpreting the results showing increased cooling efficiency with the cross-drilled rotors. On System 1, tests at 50kph, 100kph, and 160kph, showed an increase of cooling values (hA) of 8.8%, 12.1%, and 20.1% on the front and -3.2%, 1.9%, and 8.5% on the rear. For System 2, the values at 50kph, 110kph, and 140kph are 7.8%, 10.4%, and 12.1% for the front and 4.1%, 7.7%, and 13.4% rear. The other key piece of data is the raw hA numbers. At 160kph, the average hA for the front rotors of System 1 is 19.26 for the plain rotors and 23.13 for the cross-drilled. By comparison, the System 2 values at 140kph are 23.35 for the plain rotors and 26.18 for the drilled. While cross-drilling does improve the cooling rate, the degree of benefit is inversely proportional to the size of the rotor. From a pure cooling rate consideration, the plain rotors of System 2 outperform the cross-drilled rotors of System 1. Using cross-drilled rotors would seem to make the most sense only after you have run out of options for increasing the rotor diameter.

Pad wear on cross-drilled rotors was also shown to be up to up to 50% greater under hard use, and about 25~30% greater under street use. What was not explicitly tested was the effect of this increased wear on temperature because the thinner the pad, the higher the pad temp. My suspicion is that at some point, the diminished heat capacity of the pad due to wear more than offsets the gain in cooling capacity of the cross-drilled rotors. This is one reason behind many of the catastrophic failures of cross-drilled rotors at the track. Basically, they will start off strong, but the accelerated rate of pad wear soon drives the rotor into an overheated condition.

Some of the other data and conclusions from the paper on cross-drilled rotors:
• There is no practical difference in wet weather performance.
• Pad outgassing is not factor
• Thermal fatigue life is significantly shorter for cross-drilled rotors. In the case of poorly balanced and possibly under-sized System 1, by as much as 50%.
• Drilled rotors do run cooler in certain conditions
• Pad wear with drilled rotors can be a concern


Taking all of that into consideration, there is no real compelling performance reason to use drilled rotors on car you plan on taking to the track. When you factor in that that rotors will fail sooner and eat pads quicker, I don’t know why you would use them at all for any kind of passenger car performance application.

See, now you're just trying to obfuscate the issue with a bunch of diversionary BS. Maybe you're really the French soldier from the Holy Grail ...

"You don't frighten us, English pig dogs. Go and boil your bottoms, you sons of a silly person. I blow my nose at you, so-called "Arthur King," you and all your silly English K-nig-hts."

Tell you what, why don't you just post up the entire SAE paper if you have it, or just post a link to it. That way all interested parties can draw their own inferences rather than being forced to rely on yours. I think that would be immeasurably constructive and put all the facts out in the light of day.

I, for one, can see several fallacies in your reasoning above, but they're not worth pursuing with an individual so firmly entrenched in his own position.

:thumbsup:

 

[LargeOrangeFont]

See, now you're just trying to obfuscate the issue with a bunch of diversionary BS. Maybe you're really the French soldier from the Holy Grail ...

"You don't frighten us, English pig dogs. Go and boil your bottoms, you sons of a silly person. I blow my nose at you, so-called "Arthur King," you and all your silly English K-nig-hts."

Tell you what, why don't you just post up the entire SAE paper if you have it, or just post a link to it. That way all interested parties can draw their own inferences rather than being forced to rely on yours. I think that would be immeasurably constructive and put all the facts out in the light of day.

I, for one, can see several fallacies in your reasoning above, but they're not worth pursuing with an individual so firmly entrenched in his on position.

:thumbsup:

How is actual info from the paper itself BS?? Is it because you quoted a blurb you liked out of context and I responded with some actual information from the paper?

The paper is $14. if you want it, buy it.

 

[Taz]

How is actual info from the paper itself BS?? Is it because you quoted a blurb you liked out of context and I responded with some actual information from the paper?

The paper is $14. if you want it, buy it.

Mark Twain once said that there were three degrees of liars: liars, damned liars, and statisticians, in that order. In other words, anything can be taken out of context to support your position.

You said you'd send the paper to me, didn't you? Okay, send it, and I'll post it up.



EDIT: This is what you said BEFORE you thought it would be a BAD idea and edited out your offer ...

"You actually need to read the WHOLE paper… I have it and can email it to you if you would like. It is geared toward OEM style braking systems, not systems that are oriented for track use on a passenger car."

 

[LargeOrangeFont]

Mark Twain once said that there were three degrees of liars: liars, damned liars, and statisticians, in that order. In other words, anything can be taken out of context to support your position.

You said you'd send the paper to me, didn't you? Okay, send it, and I'll post it up.

So that makes me a realist, you a liar, and the GM engineers that wrote the paper stasisticians. :lol1:

It would be a bad idea for me to email copywritten documents to you, and for you to then post them up on public forums. I will send you the link to obtain a copy of your own.

The Effect of Rotor Crossdrilling on Brake Performance

 

[Taz]

It's amazing what a little creative editing can do, isn't it?

Part of your last post BEFORE editing ...

"So that makes me a realist, you a liar, and the GM engineers that wrote the paper stasisticians. :lol1:

I didn't say I'd send it to you, but I will send you the link to obtain a copy of your own."

You didn't say you'd send it to me? Gee, then this email I received from SVTP was erroneous?

Dear Taz,

LargeOrangeFont has just replied to a thread you have subscribed to entitled - Ordering my brakes today! Few last minute questions.. - in the Suspension Modifications forum of SVTPerformance.

This thread is located at:
http://www.svtperformance.com/forum...today-few-last-minute-questions-new-post.html

Here is the message that has just been posted:
***************
You actually need to read the WHOLE paper… I have it and can email it to you if you would like. It is geared toward OEM style braking systems, not systems that are oriented for track use on a passenger car. ...



That was before you edited out your offer in THAT post. So which of us does this make a LIAR? You're not helping your credibility one bit.

:dw:

 

[Taz]

Alrighty, then! I have just purchased and downloaded the entire SAE paper in question, because I'm determined to understand the TRUTH of this thing. The paper is 26 pages in length, so I have only skimmed it at this point, but from what I've read so far, it appears to support the synopsis I quoted earlier, rather than the position voiced by LOF.

My original intention was to publish the paper to my own website and provide a link to it there, but I had to agree to the following, so I urge all who are genuinely interested in learning the the truth to pay the few dollars required to obtain personal copies.

Copyright: This Document is copyrighted. No rights therein are granted except as set forth in this License. Any copying, transmission, modification or reproduction of the copyrighted material, in part or in whole, except as herein permitted is cause for revocation of this License.

License: SAE hereby grants you a nonexclusive, nontransferable right to download this document in an electronic format for your individual use on one computer. One copy of the document can be printed for individual use. The document may not be copied in any form for distribution to other users or other computers.

General: Documents that have been successfully downloaded cannot be returned for refund or credit. This Agreement is the complete and exclusive statement of the agreement between you and SAE and supersedes any and all prior agreements or understandings, either written or oral, concerning the subject of this Agreement. Any modifications must be in writing and signed by the parties.

This License shall terminate upon violation of any of its terms.

YOU ACKNOWLEDGE THAT YOU HAVE READ THIS USER LICENSE AGREEMENT, UNDERSTAND IT AND AGREE TO BE BOUND BY THE TERMS AND CONDITIONS THEREOF.

I will study the paper in depth tomorrow, but not tonight. After I've had a chance to read through it at length, I'll provide my own synopsis, which you may or may not choose to discount and/or disbelieve, but the option to download your own copy will always be there.

:coolman:

 

[jrgoffin]

You actually need to read the WHOLE paper. I actually have it.. It is geared toward OEM style braking systems, not systems that are oriented for track use on a passenger car. There is no actual performance numbers given in the paper, and that is by design. There are only differences in temperatures, and friction noted. These factors will relate to consistency, and repeatability and feel.

One of the considerations in the paper is that they used semi-metallic brake pads (generally medium performance street pads) for all the testing. These typically have a max operating temp rating of about 500~550 deg C. Also the primary functional mechanism of this type of pad is abrasion rather than adhesion. By contrast, the higher temp rated race type pads are more biased towards an adhesive mechanism relying upon a transfer layer of material deposited on the rotor.

Where this comes in to play is in interpreting the test data that shows higher apparent friction and deceleration gain for the plain rotor at low temp, the cross-drilled rotor at higher temp, and generally greater temperature fade stability for the cross-drilled. At low temp, the greater surface area of the plain rotor is the dominant performance factor, as one would expect. At higher temps however, the breakdown of the pad is the dominant consideration and the cheese grater effect of the cross-drilled rotors helps to compensate for this by providing increased mechanical friction.

If however, this test were to be repeated with a higher temp rated adhesive type race pad, I'd expect the results to be exactly the opposite. That is at lower temps where you would expect the race pad to perform poorly, the cross-drilled rotors would provide an abrasive mechanism and increased performance. But at higher temps, not only would the lesser surface area of the cross-drilled rotor become the dominant consideration, but the abrasive mechanism of the holes would inhibit proper formation of the transfer layer.

Another interesting aspect is the wide base performance difference between the three brake systems used in the test. "System 3" appears to be an overall poor performer in comparison with the other 2 systems. In the case of System 3, the cross drilling appears to be a pure bling change, as it is rather consistently outperformed by the plain rotors, despite their being smaller in overall diameter. System 1 was a better performer, but quite unbalanced. Almost all the work on this system was being done by the front rotors. System 2 looks to be the best of the lot, and consequently showed the least radical performance deviations between the plain and cross-drilled rotors.

The base performance difference between System 1 and System 2 helps in interpreting the results showing increased cooling efficiency with the cross-drilled rotors. On System 1, tests at 50kph, 100kph, and 160kph, showed an increase of cooling values (hA) of 8.8%, 12.1%, and 20.1% on the front and -3.2%, 1.9%, and 8.5% on the rear. For System 2, the values at 50kph, 110kph, and 140kph are 7.8%, 10.4%, and 12.1% for the front and 4.1%, 7.7%, and 13.4% rear. The other key piece of data is the raw hA numbers. At 160kph, the average hA for the front rotors of System 1 is 19.26 for the plain rotors and 23.13 for the cross-drilled. By comparison, the System 2 values at 140kph are 23.35 for the plain rotors and 26.18 for the drilled. While cross-drilling does improve the cooling rate, the degree of benefit is inversely proportional to the size of the rotor. From a pure cooling rate consideration, the plain rotors of System 2 outperform the cross-drilled rotors of System 1. Using cross-drilled rotors would seem to make the most sense only after you have run out of options for increasing the rotor diameter.

Pad wear on cross-drilled rotors was also shown to be up to up to 50% greater under hard use, and about 25~30% greater under street use. What was not explicitly tested was the effect of this increased wear on temperature because the thinner the pad, the higher the pad temp. My suspicion is that at some point, the diminished heat capacity of the pad due to wear more than offsets the gain in cooling capacity of the cross-drilled rotors. This is one reason behind many of the catastrophic failures of cross-drilled rotors at the track. Basically, they will start off strong, but the accelerated rate of pad wear soon drives the rotor into an overheated condition.

Some of the other data and conclusions from the paper on cross-drilled rotors:
• There is no practical difference in wet weather performance.
• Pad outgassing is not factor
• Thermal fatigue life is significantly shorter for cross-drilled rotors. In the case of poorly balanced and possibly under-sized System 1, by as much as 50%.
• Drilled rotors do run cooler in certain conditions
• Pad wear with drilled rotors can be a concern


Taking all of that into consideration, there is no real compelling performance reason to use drilled rotors on car you plan on taking to the track. When you factor in that that rotors will fail sooner and eat pads quicker, I don’t know why you would use them at all for any kind of passenger car performance application.

Popular debate...

[ame=http://www.e46fanatics.com/forum/showthread.php?t=500950]The Effect of Rotor Crossdrilling on Brake Performance - E46Fanatics[/ame]

 

[Taz]

jpr over there appears to be LOF over here.

 

[mu22stang]

Wow, this is pretty rare. A thread in the SVTP Suspension forum with tech!

Let's continue without all the ad hominem, name calling, BS.

 

[Taz]

Alrighty, then! You want tech? Here ya go ...

Synopsis of SAE Tech Paper 2006-01-0691


Enjoy!

:thumbsup:

 

[jrgoffin]

:thumbsup: