More on drilled vs. slotted rotors
#76
Rotary Freak
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I always heard that rotors are slotted or drilled to allow gases to escape. Supposidly there is a build up of gas between between the pad and the rotor and that gas forms a thin layer that prevents the pad from making full contact with the rotor. The slots or drilled holes allow that gas to escape under hard braking. It helps to prevent brake fade. Anyways thats what I was told, it seems to make sense to me. I could be wrong but so far it seems pretty logical.
#77
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Thread Starter
Originally Posted by usmcjsy
I always heard that rotors are slotted or drilled to allow gases to escape. Supposidly there is a build up of gas between between the pad and the rotor and that gas forms a thin layer that prevents the pad from making full contact with the rotor. The slots or drilled holes allow that gas to escape under hard braking. It helps to prevent brake fade. Anyways thats what I was told, it seems to make sense to me. I could be wrong but so far it seems pretty logical.
#78
Respecognize!
well seeing that people will buy anything even if it doesnt do something, i should make 25.3and 1/2 " brake kits. Hondas tuners would be on that like white on rice in a snow storm (<-- thanx major payne!)
#79
Rotary Freak
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Sorry I did not read the 1st page, my mistake. If I would have I would have seen that theory already covered. Anyway I agree if nothing else they do look better than the non slotted or drilled ones. I really do not believe anyone can say they have not bought anything just because of the looks before for their car. Thanks for the info though it was interesting.
#80
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Originally Posted by RETed
Why are people so stubborn about this?
They are done for weight reduction.
When you're talking about top-tier racing like that, there are restrictions.
Did you confirm with their (brake) engineers about why they brake rotors are designed like that?
Yeah...I thought you didn't...
-Ted
They are done for weight reduction.
When you're talking about top-tier racing like that, there are restrictions.
Did you confirm with their (brake) engineers about why they brake rotors are designed like that?
Yeah...I thought you didn't...
-Ted
#81
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Originally Posted by jimlab
Are these full moon-shaped holes we're talking about or crescent moon-shaped holes we're talking about? Were there any pink hearts or yellow diamonds?
BTW its Pink hearts, yellow moons and blue diamonds with their newest addition of purple horseshoes.
#82
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A few pages back it was noted that Porsche uses rotors with holes in them (whether they are cross-drilled or cast). I'm not 100% sure, but look at their race cars. They use solid rotors...why then would they use rotors with holes in their street cars??? Because, to most avg. Joe's with that much $$, it's a "performance" thing and they don't know any better, but they sure as hell think it looks good.
#83
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those "holes" you saw on the race cars, are more than likely "dimples" they aren't crsooed drilled, more llike slotted rotors, but they are little dots on the rotors...iono where to find a pic, but i know those rotors exists...
#85
R.I.P. Monte Negro FD
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regardless. i am so into looks then. cuz i got the ebay brembo cross drilled slotted and i cant complain, everyone always looks and the rotors. since the are visible thru the 17 crome momo sports. again, i am into the looks, i never track my car, so it doesnt matter. i'll always support a company that will make my ride look like the hot lil bitch she is lol
#86
Lives on the Forum
Originally Posted by overkill
Now why should I need to confer with a brake engineer? Someone stated that ALMS cars do not use cross-drilled rotors. When I was there, I saw race cars using them. We are not dicussing WHY they are used, we were dicussing the issue if they were used in ALMS .
YOU are CLAIMING that the drilling is due to better brake performance.
I asked YOU to ASK the BRAKE ENGINEER for the REASON why the brake rotors are drilled.
IF they are consistent with YOUR CLAIM, then YOU are CORRECT.
If it is NOT, you are WRONG.
Is there a problem understanding what I am trying to say here?
I mention restriction, cause some race sanctions (look at F1) have restrictions on brake (rotor) size.
Specifically F1, the wheel dimensions are specified in the rule book.
This directly affects brake rotor size, since you can only physically stuff an x" diameter brake rotor in the maximum wheel size.
Now, if the wheel size is sufficiently large, why not go with the largest brake rotor you can fit?
Now, going with large brake rotors also increases unspring weight.
Upsprung weight is BAD.
So run the largest rotor you can fit (gives you superior "moment arm" [I forgot the right term right now] leverage from the brake pad - this allows you finer control of the brake pads on the brake rotor), but drill the rotors as light as you can to decrease unsprung weight in the corners.
WOW, what a concept!
Brake performance is sacrificed for less weight, but since the rotors are oversized, the slight decrease in brake performance is not enough to be significant in this case.
This has NOTHING to do with braking performance.
This has EVERYTHING to do with less weight.
And, if you've ever seen top-tier racing parts, some of these brake rotors have wear grooves or dimples.
There are several slots or dimples which are milled to a specific depth, and these are used are wear guides.
This is especially true for endurancing racing (ala Daytona 24 Hours, which ALMS does), as a quick look at a certain set of slots or dimples will quickly tell you if the brake rotor is in need of replacement.
-Ted
#87
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Originally Posted by RETed
Then you didn't understand my my reply.
YOU are CLAIMING that the drilling is due to better brake performance.
I asked YOU to ASK the BRAKE ENGINEER for the REASON why the brake rotors are drilled.
IF they are consistent with YOUR CLAIM, then YOU are CORRECT.
If it is NOT, you are WRONG.
Is there a problem understanding what I am trying to say here?
I mention restriction, cause some race sanctions (look at F1) have restrictions on brake (rotor) size.
Specifically F1, the wheel dimensions are specified in the rule book.
This directly affects brake rotor size, since you can only physically stuff an x" diameter brake rotor in the maximum wheel size.
Now, if the wheel size is sufficiently large, why not go with the largest brake rotor you can fit?
Now, going with large brake rotors also increases unspring weight.
Upsprung weight is BAD.
So run the largest rotor you can fit (gives you superior "moment arm" [I forgot the right term right now] leverage from the brake pad - this allows you finer control of the brake pads on the brake rotor), but drill the rotors as light as you can to decrease unsprung weight in the corners.
WOW, what a concept!
Brake performance is sacrificed for less weight, but since the rotors are oversized, the slight decrease in brake performance is not enough to be significant in this case.
This has NOTHING to do with braking performance.
This has EVERYTHING to do with less weight.
And, if you've ever seen top-tier racing parts, some of these brake rotors have wear grooves or dimples.
There are several slots or dimples which are milled to a specific depth, and these are used are wear guides.
This is especially true for endurancing racing (ala Daytona 24 Hours, which ALMS does), as a quick look at a certain set of slots or dimples will quickly tell you if the brake rotor is in need of replacement.
-Ted
YOU are CLAIMING that the drilling is due to better brake performance.
I asked YOU to ASK the BRAKE ENGINEER for the REASON why the brake rotors are drilled.
IF they are consistent with YOUR CLAIM, then YOU are CORRECT.
If it is NOT, you are WRONG.
Is there a problem understanding what I am trying to say here?
I mention restriction, cause some race sanctions (look at F1) have restrictions on brake (rotor) size.
Specifically F1, the wheel dimensions are specified in the rule book.
This directly affects brake rotor size, since you can only physically stuff an x" diameter brake rotor in the maximum wheel size.
Now, if the wheel size is sufficiently large, why not go with the largest brake rotor you can fit?
Now, going with large brake rotors also increases unspring weight.
Upsprung weight is BAD.
So run the largest rotor you can fit (gives you superior "moment arm" [I forgot the right term right now] leverage from the brake pad - this allows you finer control of the brake pads on the brake rotor), but drill the rotors as light as you can to decrease unsprung weight in the corners.
WOW, what a concept!
Brake performance is sacrificed for less weight, but since the rotors are oversized, the slight decrease in brake performance is not enough to be significant in this case.
This has NOTHING to do with braking performance.
This has EVERYTHING to do with less weight.
And, if you've ever seen top-tier racing parts, some of these brake rotors have wear grooves or dimples.
There are several slots or dimples which are milled to a specific depth, and these are used are wear guides.
This is especially true for endurancing racing (ala Daytona 24 Hours, which ALMS does), as a quick look at a certain set of slots or dimples will quickly tell you if the brake rotor is in need of replacement.
-Ted
I simply replied to someone stating that ALMS does not use drilled rotors. He claimed they did not. I claim that they did because I saw them on the cars when I watched the race at Infineon Raceway. They were not drilled out holes per say, rather they were half circles, kind of like moon shaped. They were not dimples for I could plainly see daylight through them. The holes were either milled out, or punched. If I had to guess, they were milled on a lathe. I cannot see how you can get so confused about what my point is. Is it that cryptic that you cannot understand?
You asked me if there was a problem understanding you and the answer is yes. The problem is that YOU DO NOT PAY ATTENTION to what I have said in my posts. If you had, you would clearly see that we are talking about two entirely different topics.
#89
First hand experience... I put cross-drilled Brembo (which were drop-shipped from the factory, btw, so apparently they do drill their own) rotors on my FD with high-performance pads. One day of lapping and they were completely cracked. Spider cracks at every hole, and cracked all the way through in several places. Completely unusable.
So I tried slotted Brembo rotors this past weekend. One day of lapping and they were warped badly, but with no evident cracks.
I replaced them with my OEM '93 rotors (desperation backups) and FINISHED THE WEEKEND with excellent braking and with no further warping or cracking problems!
So I don't know if that means Brembo are crap, or if both cross-drilled and slotted rotors are crap, but I know I will be trying simple OEM replacement rotors at my next event - besides, there is a 1 year replacement warrantee on rotors from most parts stores.
Oh, and my understanding is that Brembo does drill/slot their own rotors and markets them as their "Sports Rotors". They are otherwise identical to their basic rotors.
So I tried slotted Brembo rotors this past weekend. One day of lapping and they were warped badly, but with no evident cracks.
I replaced them with my OEM '93 rotors (desperation backups) and FINISHED THE WEEKEND with excellent braking and with no further warping or cracking problems!
So I don't know if that means Brembo are crap, or if both cross-drilled and slotted rotors are crap, but I know I will be trying simple OEM replacement rotors at my next event - besides, there is a 1 year replacement warrantee on rotors from most parts stores.
Oh, and my understanding is that Brembo does drill/slot their own rotors and markets them as their "Sports Rotors". They are otherwise identical to their basic rotors.
#90
Coming to a track near u!
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To clear up the ALMS evidence... I travel with the ALMS Series and SPEED World Challenge on field staff as an Official with the SCCA. I do not recall seing any ALMS cars with cross-drilled brakes in my last 5 years with the series. The only holes I believe you'll see in ALMS are round ones around the circumfrence drilled inwards. This is an easy way to identify Carbon rotors which cost $10,000 to $20,000 a set fyi. In World Challenge we have a few cars with cross-drilled rear breaks to the point they are swiss cheese but this is because they are front wheel drive and the bias setting reduces the braking duty on the rears greatly.
I can't think of any well-respected professional or amateur motorsports class/chassis that uses cross-drilled on all four corners if at all. So I figure the engineers have the right conclusion.
Gas-slotted is the most widely accepted HIGH performance brake rotor option.
As for above, just as you have to learn to manage tires in a race or lapping you have to learn how to manage your brakes correctly.
I can't think of any well-respected professional or amateur motorsports class/chassis that uses cross-drilled on all four corners if at all. So I figure the engineers have the right conclusion.
Gas-slotted is the most widely accepted HIGH performance brake rotor option.
As for above, just as you have to learn to manage tires in a race or lapping you have to learn how to manage your brakes correctly.
#91
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Originally Posted by racerjason
To clear up the ALMS evidence... I travel with the ALMS Series and SPEED World Challenge on field staff as an Official with the SCCA. I do not recall seing any ALMS cars with cross-drilled brakes in my last 5 years with the series...
I can't think of any well-respected professional or amateur motorsports class/chassis that uses cross-drilled on all four corners if at all.
I can't think of any well-respected professional or amateur motorsports class/chassis that uses cross-drilled on all four corners if at all.
#92
FD3SW211E55
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Crescent moons.....
Overkill says that he saw rotors with crescent moon holes. I haven't seen anything similar that goes all the way through the rotor, but I have seen references to crescent shaped slots. The curve on these slots is tighter than the half-slots that Damon posted. Stasis Engineering sells such rotors, apparently made from Alcon blanks:
http://www.stasisengineering.com/details/rotor.shtml
Sport Compact Car tested a set on an EVO in the September 2004 issue:
http://www.sportcompactcarweb.com/pr...vo/index1.html
I know no one that actually uses these rotors. I also hereby state for the record that I neither endorse, nor disapprove of this product, and my comments should not be construed to contain any positive or negative undertones and/or overtones with respect to the subject matter hereof...
http://www.stasisengineering.com/details/rotor.shtml
Sport Compact Car tested a set on an EVO in the September 2004 issue:
http://www.sportcompactcarweb.com/pr...vo/index1.html
I know no one that actually uses these rotors. I also hereby state for the record that I neither endorse, nor disapprove of this product, and my comments should not be construed to contain any positive or negative undertones and/or overtones with respect to the subject matter hereof...
#93
Super Snuggles
Once a CNC machine is involved, you could have purple hearts, orange moons, yellow diamonds, and blue clovers cut into the surface of the rotor if you wanted. Or tiny rotor shapes...
#94
Savanna Rx-7
I know they won't believe me but....
Originally Posted by DamonB
Hear! Hear! Maybe they'll believe YOU. They never believe me
Being the poor broke bastard I am, I used to cross drill my rotors on a drill press, and then chamfer them with a burr bit, thinking I was helping myself save money while hill racing on Okinawa, but a JN friend of mine one day come up after I cracked another set, and basically gave me the same spiel about the outgassing, cracking and whatnot. I didn't believe him at the time, so we made a bet. needless to say several bets later I gave up, as his stock rotors (from a different car) always lasted longer on his SA than mine did. after loseing about 30000 in bets (yen fortunately!) I tried the same rotors he had been useing , and several races later, were stil useing them (albeit lathed slightly for finish) thats when I found out he had been useing the SAME set the whole time we were betting, and used the money he saved, (and mine) to buy a new header.
DAMN can you say trippin over your dick! I found out that he had found out basically the same way from one of his friends, and was trying to recoup his money when he approached me for the bet!
honestly this isn't BS true story, 14 years ago, and I ain't drilled no more since then. another note, I have never tried the slotted type due to cost over here.
cheers
Ken
#96
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Thread Starter
Originally Posted by oorx7
so, dare I ask witch way the slots should be directed.
#97
Are there rotars with small slots? The ones I've seen seem to be exceptionally large concidering there is a small amount of gas build up. I would think that a tiny indent would sufice, while still maintaining a high amount of contact area and minimal stress.
#98
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Originally Posted by C-Murder
Are there rotars with small slots? The ones I've seen seem to be exceptionally large concidering there is a small amount of gas build up.
#99
DETH TRP
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Originally Posted by DamonB
I'm sure some people also still believe the earth is flat, man never went to the moon and that dinosaurs still live in a jungle somewhere. You can't convince those who have made up their minds already
There was pretty good motive for faking too, and who would catch it...the American public .