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    1. #1
      Join Date
      Dec 2002
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      The original crossdrilled and slotted discussion (from old site)

      Ralph L
      Moderator
      Posts: 3016
      (4/12/04 9:03 pm)
      Reply
      Drilled and Slotted Rotors - Discussion
      --------------------------------------------------------------------------------
      This is in response to Tom's post in Andrew's thread. Rather than hijack the thread, I figured I'd start a new one.

      Tom, could you give us the cliff-noted version, please. I read through the first page(I will try and read more tomorrow) and found nothing but the guy saying how much he loved them, and people asking for pics...I have drilled and slotted rotors going on my car, and they might have been the one thing that I didn't research. All I knew was that drilled and slotted = better or so I thought. When Larry was contemplating the d/s rotors over regular, only then did I find out there are downsides to d/s rotors.

      I'm not talking about on the street, but on the track. I'm not particularly concerned about me roasting my rotors on the street, there's not where on LI to drive like that, lol. But I sure as hell don't want to be coming up on a turn after a long straight-away at 160mph, only to find out that I'm about to crash into the wall becasue I just cracked my rotors or something...

      Take your sides, gentlemen!
      Ralph
      Project Fantom Expected Completion - May 2005
      My Tahoe - "Black Mamba"
      Rendering of Project Fantom

      protour2001
      Registered User
      Posts: 154
      (4/12/04 10:08 pm)
      Reply Re: Drilled and Slotted Rotors - Discussion
      --------------------------------------------------------------------------------
      Hey Ralph, read the second page(at least) of the Altimas thread-that's where the fireworks start. The C-C guys are not real subtle(!), but there's a ton of good info in between attacks and counter attacks.

      If you're going Opentracking, I would stay away from drilled rotors, and probably slotted also. The only possible exception may be the Porsche rotors, if they are available for your setup.

      For whatever reason, this seems to be one of the biggest controversies on the internet(car related). You will be able to find passionate opinions from both sides. My personal opinion is that you will never find crossdrilled/slotted rotors on any of my cars. Period.

      Brian

      chicane67
      Registered User
      Posts: 32
      (4/12/04 10:36 pm)
      Reply | Edit Re: Drilled and Slotted Rotors - Discussion
      --------------------------------------------------------------------------------
      OK, I'll try and sum this up for you guy's. First and foremost, before you read the actual thread itself, you will need to know a little back ground on those involved. The thread in question doesnt get really good until about page ten or eleven..........

      In one hand, you have a vendor of aftermarket import parts that has no 'real' experience to speak of. In the other hand you a few cats from corner-carvers.com. The cats over on cc.com have their proverbial she-ot together. Some of you will love their site and some not, but there are a couple things you should be aware of. These guys are viscious, some other people think alot of them have no lives and live only for bashing and challenging words that people post. Cc.com can be amazing. In many other sites, they don't allow vendors to participate, in here, they encourage it. There is no question, they will challenge everything that you state, so just be aware of this. If you can't back it up with the tech, they will tear you apart.

      They are also really good at helping out, it is all a matter of how you come across and the things that you write. There is an infamous thread on Total Control Products, where they the manufacturers jumped in to defend their products, and got slaughtered. In the eyes of a few, it damaged the reputation of the company. In short, the TCP guys could not back up the tech, and the guys at cc.com tore them apart.

      They don't care about polish, powder coating, or anything that looks good but doesn't work. In fact, they tend to really harp on the bling factor. These guys are all about performance, engineered and proven. Oh yea, and one more thing, use spell check and check your grammar, another pet peeve of the cc.com site. I dont recommend anyone just jumping into their threads without knowning that if you funk it up, you will have your ass handed to you, promptly. I used to work with, for and around this type when I was in the business and hanging around the tracks....so its nothing new to me, but be warned....these cats live, eat and breath hard core tech.

      The issue. What all of this stems from is about cross drilled rotors and the real story behind them. The import vendor threw out some information that was, well, half assed and not correct by any means. When he was questioned about it, and was provided with all of the emperical data in the world, it could not bend him from his point of view......no matter how incorrect the information he was giving is/was and what the reprecussions were. Basically, they lit this guy on fire with raw engineering data and theory.

      Basically what the end holds, is that cross drilling rotors is a real no-no and I agree. I dont run them and never have unless my customer just has to have, what he/she considers to be the bling bling, but they get that news up front from me firsthand.

      You wanted me to put this is the respect of 'track use' and not necessarily street use, but it applies just the same. The negative out weights the positive in all seriousness. Most people here have little if any experience in the realms of high performance driving. Not to forget to mention, doing it door to door at a high rate of speed. There are so many factors to what has to happen, that a rookie mistake either driving or in parts selection can cost you more than just some replacement fenders. Some people here havent liked my approach in certain respects, but then again, you dont strap inexperienced and over confident "check wrighters" (those damn checkbook guys again) into cars that have the potential to go 200+ MPH. Nor do you see me telling you to purchase something that I myself and others with ten times my experience, wouldnt run themselves. We have already had our little liability arguement on and about a certain suspension component that got quite ugly....enough said? You need to understand that when things are stated, to take them seriously......I am sure you wouldnt want a rotor coming apart on you at any time right?

      The be all to end all. This pretty much sums it up:

      1) No matter what, a drilled and/or slotted rotor will eventually fail. Period, no questions. See pictures below.

      2) With the pad compounds we have available today, any needs and use for a drilled rotor have been eliminated, with the exception of use in some wet environments.

      3) The increase in surface area exposed to the available cooling air is offset by its reduction in overall mass available to absorb heat energy.

      4) If the holes are cast in giving a dense boundary layer-type crystalline grain structure around the hole at the microscopic level as opposed to drilling which cuts holes in the existing grain pattern leaving open endgrains, etc, it's just begging for cracks. AKA "stress risers".

      The exception to this is the Porche rotor. But, it too is still prone to the same damage from expansion and contraction during hard use. To further support this, I will expand on a thing or two:

      5) The holes are only half the diameter of the holes in most drilled rotors. This reduces the stress concentration factor due to hole interaction which is a function (not linear) of hole diameters and the distance between them.

      6) Since the holes are only 1/2 as big they remove only 1/4 as much surface area and mass from the rotor faces as a larger hole. This does a couple of things:

      a) It increases effective pad area compared with larger holes. The larger the pad area the cooler they will run, all else being equal. If the same amount of heat is generated over a larger surface area it will result in a lower temperature for both surfaces.

      b) It increases the mass the rotor faces have to absorb heat with. If the same amount of heat is put into a rotor with a larger mass, it will result in a lower temperature.

      7) The holes are placed along the vanes, actually cutting into them giving the vane a "half moon" cut along its width. You can see that here:




      This does a couple of things:

      First, it greatly increases the surface area of the vanes which allows the entire rotors to run cooler which helps prevent cracks by itself.

      Second, it effectively stops cracking on that side of the hole which makes it very difficult to get "hole to hole" cracks that go all the way through the face rotor (you'll get tiny surface "spider cracks" on any rotor, blank included if you look hard enough).

      These are real nice. Love to run these wouldnt ya?





      ** The majority contributors and writers of this information that I have paraphrased are not limited to but include Jon A., Brian K., Lewis T., MaddMatt and Drew M. of cc.com**


      Edited by: chicane67 at: 4/13/04 4:55 pm

      ddennis68
      Registered User
      Posts: 83
      (4/12/04 11:22 pm)
      Reply Re: Drilled and Slotted Rotors - Discussion
      --------------------------------------------------------------------------------
      As always, well written chicane. Alot of good info there. I work with the worst offenders of car manufacters' inadequetly braking their vehicles'. Of course, I'm talking about Jeep. We have a barrel outside the shop about 4 feet tall and 5 feet in diameter that we weekly fill with old rotors and calipers off Grand Cherokee's. Some of our customers have tried the drilled/slotted approach to preventing warped rotors and in some cases have had success with prolonging the inevidable at the sacrafice of poor braking performance. Bottom line, the factory doesn't use them and beleive me they spend a ton of $$$$ repairing brakes under warranty. If the drilled/slotted thing worked, wouldn't the Viper, Z06, and Roush Mustang use them? Manufacters' spend huge money developing/testing the brakes on these cars. Just something to think about.


      check out progress of WKDTITE

      KacyZ28
      Registered User
      Posts: 240
      (4/13/04 5:37 pm)
      Reply
      Re: Drilled and Slotted Rotors - Discussion
      --------------------------------------------------------------------------------
      i have a friend that put a set od auto specialty drilled rotors on his 98 camaro and he replaced them due to heat cracks from the drilled holes from driving on the street
      69 camaro project



      Ralph L
      Moderator
      Posts: 3023
      (4/13/04 6:04 pm)
      Reply
      Dammit!
      --------------------------------------------------------------------------------
      Thanks much for the info, Tom.

      Wow, this really sucks. I bought drilled and slotted because I was sure they are better. Maybe I'll just run them on the street, and swap them out for regular rotors for track use.

      Anyone know how much it is to buy just the rotor from Wilwood?
      Ralph
      Project Fantom Expected Completion - May 2005
      My Tahoe - "Black Mamba"
      Rendering of Project Fantom

      gmachinz
      Unregistered User
      (4/13/04 8:40 pm)
      Reply ouch....
      --------------------------------------------------------------------------------
      This all reminds me of when I first seen "Aimco" come out with their "Extreme" series of rotors-which are nothing more than Raybestos-type rejects that failed their tests for optimum quality but were bought by a cheaper "brake company" and then had the slots and drills added later. I can tell you this is true because I used to work with various vendors for an automotive parts store and I have a lot of knowledge from both them and the actual owner of the stores I worked for that gave me an insight as to why there always seems to be a cheaper version of something expensive. It all seems to boil down to the fact that there were originally a rejected part by a larger company which was bought by somebody else cheap and is marketed as an "alternative". Sheesh. This is why I say stay away from parts store cheapies and deal with reputable companies that actually manufacture the stuff. Sometimes getting it from the source is the best way to go. -G

      chicane67
      Registered User
      Posts: 33
      (4/13/04 11:04 pm)
      Reply | Edit Re: ouch....
      --------------------------------------------------------------------------------
      But Ralph, they are better........Looking..........

      Honestly, I dont see most having too many problems with the BAER products and possibly some of the others for low effort use. As long as you are aware of what can happen and that you pay attention to doing regular check ups....to include all other systems, not just the brakes....I think that for street use, they will do.

      Now as for the track, no. Solid all the way.....and it wasnt really mentioned anywhere but you do get better/shorter stopping distances from solid rotors. Of course no one will own up to it, because they want to sell you a more expensive rotor. But Raplh, you have brought up something else that many might want to consider. A seperate set of rotors and their own pads for track use.



      1) Any problems and you have a back up set that you can drive on.

      2) you can use a more aggressive set of pads at the track, but wont eat them up during street use.

      3) Some pads dont like to be mixed on a rotor surface.

      I normally like to run a type of pad with a single rotor and not mix them if I were to change them out for a track weekend per-se. That way I get maximum use out of both sets of pads and rotors.

      But for what all of this is worth, just be careful and WATCH for witness during your inspection. A little PM will save your booty.....hineie and pile-o-cash, for that matter.

      And Ralph, dont sweat it too much....the solid rotors are cheaper anyway !!

      parsonsj
      Registered User
      Posts: 1575
      (4/14/04 6:29 am)
      Reply Separate rotors for track use
      --------------------------------------------------------------------------------
      I agree: It is probably a very good idea to use different rotors and pads on the track. A good all-day-long track session will likely eat your pads and rotors anyway. Ralph, don't you have Wilwood stuff? Swapping rotors and pads is child's play on my Wilwoods ... assuming you have the cash for the alternate set.

      John Parsons


      72SSAbody
      Registered User
      Posts: 60
      (4/14/04 7:32 am)
      Reply .
      --------------------------------------------------------------------------------
      Chicane, glad to see someone else understands why the d/s rotors aren't better. My own family still can't be convinced that they are only for bling-bling factor

      I even broke out the ol' college books to show Kt and Kf that these holes bring on (especially with cyclic loads). Still not convenced

      Live and learn.

      Joe

      Ralph L
      Moderator
      Posts: 3027
      (4/14/04 9:32 am)
      Reply
      Re: .
      --------------------------------------------------------------------------------
      JP, I've got the wilwoods, same stuff as you I think, except 13 inch front rotors. I'm not concerned with swapping the rotors and pads, as you said, it's a pretty quick job. It's the fact that I have to buy another set of rotors. I guess you gotta pay to play though, I'm probably better off switching rotors and pads for track use anyways though.
      Ralph
      Project Fantom Expected Completion - May 2005
      My Tahoe - "Black Mamba"
      Rendering of Project Fantom

      protour2001
      Registered User
      Posts: 155
      (4/14/04 10:20 am)
      Reply Re: .
      --------------------------------------------------------------------------------
      For dual purpose cars, check the brakes forum at www.frrax.com -a lot of the guys there run seperate pad/rotor combos for street and track. Lots of pad compound info too, for Camaros of all generations.

      chicane
      Unregistered User
      (4/14/04 3:13 pm)
      Reply Another link for some good tech
      --------------------------------------------------------------------------------
      Here's another good read that has some darn good tech behind it.

      web.camaross.com/forums/s...ss+drilled

      chicane
      Unregistered User
      (4/14/04 3:27 pm)
      Reply More stuff to read
      --------------------------------------------------------------------------------
      And another........

      www.ws6.com/cryo.htm

      Ralph L
      Moderator
      Posts: 3029
      (4/14/04 5:25 pm)
      Reply
      Just to stir the pot a bit
      --------------------------------------------------------------------------------
      I'm not disagreeing that d/s rotors are better in any way, but I did notice something today. The new S500 Benz in the parking lot I saw had drilled rotors, and I think the C6 also has drilled rotors, possibly even the new viper?

      Are auto manufacturers really only concerned with the bling?
      Ralph
      Project Fantom Expected Completion - May 2005
      My Tahoe - "Black Mamba"
      Rendering of Project Fantom

      protour2001
      Registered User
      Posts: 156
      (4/14/04 6:11 pm)
      Reply Re: Just to stir the pot a bit
      --------------------------------------------------------------------------------
      They help sell the car, pure and simple. "And just look at these high performance brakes!"

      Edited by: protour2001 at: 4/14/04 7:32 pm

      ddennis68
      Registered User
      Posts: 89
      (4/14/04 7:19 pm)
      Reply Re: Just to stir the pot a bit
      --------------------------------------------------------------------------------
      Ralph, I haven't got any of the Vipers here yet but that would be the first I had heard of it. I was over at corvetteforum earlier and there was a discussion about the AC Delco d/s rotors and how they held up. One guy chimed in that he completely destroyed both front rotors in 40 min on the track-1.7 miles/11 turns. The rotors were literally falling apart from cracks between the holes.

      o1mrquick
      Registered User
      Posts: 1678
      (4/14/04 9:41 pm)
      Reply drilled & slotted
      --------------------------------------------------------------------------------
      Most Porsche models,Boxster, Cayenne turbo and 996's run cross drilled rotors from the factory,I am told they were replaced at time of pad service...some Z06's had them stock not sure of the year 2001 comes to my tiny mind...humm Dodge...no...I confronted a factory designer on the brake usage and questioned him why the pads are so small and his thoughts on drilled or slotted rotors.He stated the rotor size and design for heat dissipation was the most important factor in braking performance not pad size.The usage of holes or slots to release gasses produced by friction materials where not necessary due to the slots cut into the pads themselves.Incorporating slots in the pads was a cheaper and less liable solution.He said rotor life was short and where more prone to cracking thus evoking customer complaints. I like look of D/S rotor but I don't drive fast enough to heat em enough to crack either...I have a set of Autospecialty power stop rotors on my GTO and I swear it stops way better than the stock rotors.If it works for you? c-yaaaa o1

      72SSAbody
      Registered User
      Posts: 61
      (4/15/04 6:12 am)
      Reply .
      --------------------------------------------------------------------------------
      I read through some of the thread, but I don't think they mentioned the Kt that is generated by the holes....or in this case the Kf (since its a cyclic loaded part).

      One good thing about it is Kt is generally less than Kf for a cyclic part. But like that makes that big of a difference



      Ralph L
      Moderator
      Posts: 3046
      (4/15/04 11:27 am)
      Reply
      xx
      --------------------------------------------------------------------------------
      by kt and kf do you mean kinetic force?
      Ralph
      Project Fantom Expected Completion - May 2005
      My Tahoe - "Black Mamba"
      Rendering of Project Fantom

      Edited by: Ralph L at: 4/15/04 11:28 am

      Steve2000SS
      Registered User
      Posts: 260
      (4/15/04 12:36 pm)
      Reply well..
      --------------------------------------------------------------------------------
      Not all rotors with holes are "drilled".. some do have the holes drilled into the rotors while others have them cast into the rotors.

      Drilled holes are FAR FAR more prone to cracking around the holes than cast ones. It was explained to me once that it has to do with a lot of metalurgical terms i cant remember

      For example my Wilwood front rotors have the holes cast into the rotor and they are chamfered. Ive beat the crud out of them and never had a cracking problem..

      Anyways, thought that i would mention that there is a difference.. but i do agree that the holes are mostly for looks these days as outgassing is less common with the new pad materials.

      Ralph L
      Moderator
      Posts: 3051
      (4/15/04 5:59 pm)
      Reply
      Re: well..
      --------------------------------------------------------------------------------
      Knowing that they're cast makes me feel a little bit better...thanks for cearing that up, Steve.
      Ralph
      Project Fantom Expected Completion - May 2005
      My Tahoe - "Black Mamba"
      Rendering of Project Fantom

      chicane67
      Registered User
      Posts: 37
      (4/15/04 6:51 pm)
      Reply | Edit Re: well..
      --------------------------------------------------------------------------------
      Who said they were cast in? Willwood sure hasnt.....

      chicane
      Unregistered User
      (4/16/04 2:45 pm)
      Reply DOH, they lied !!!
      --------------------------------------------------------------------------------

      Quote:
      --------------------------------------------------------------------------------
      They are drilled and then finished with a machined radius to help eliminate stress risers and premature wear.
      --------------------------------------------------------------------------------



      ~Willwood

      conekiller13
      Registered User
      Posts: 714
      (4/16/04 8:26 pm)
      Reply
      Re: Drilled and Slotted Rotors - Discussion
      --------------------------------------------------------------------------------
      Mmmmm......

      I feel I'm a little late to the party. I'm going to add My .02 from what I've seen and experianced........lab results aside. Has anyone seen a rotor on an F-350 or 450? They are huge and solid. I've seen more of those crack and come apart than any other. Every set of Brembo O.E. drilled I've seen have developed "stress fractures" (Porsche, Ferrari) around the holes which Brembo has assured Me is only cosmetic damage and does not effect structual integrity. I have yet to see Baer's rotors crack including My own. Baer says the drilling and slotting are for cosmetic purposes only. I have put many set of drilled/slotted rotors on Cherokees, conversion vans, Suburbans and other S.U.V.'s that had habitual rotor warping problems that all seemed to be cured by that. I've had customers with these types of rigs that have high braking demands that have cracked and detroyed their solid rotors and replaced them with drilled rotors and no longer had problems. I'm not saying one is better or not just stating evidence from the field. It could be that these vehicls just have inferior pads compounds availible so the d/s has an effect with them............who knows. In closing I think that for a street/track car You have nothing to worry about if You have D/s rotors. Maybe in an actual race situation a problem could devolp but I doubt it on a track day.
      Daniel Kuehn '71 Pro-Tour Chevelle

      http://dankuehn.figureheadmusic.com/index.htm

      protour2001
      Registered User
      Posts: 160
      (4/17/04 8:40 am)
      Reply Re: Drilled and Slotted Rotors - Discussion
      --------------------------------------------------------------------------------

      Quote:
      --------------------------------------------------------------------------------
      I have put many set of drilled/slotted rotors on Cherokees, conversion vans, Suburbans and other S.U.V.'s that had habitual rotor warping problems that all seemed to be cured by that.
      --------------------------------------------------------------------------------


      Warped rotors? Check this out.
      www.stoptech.com/whitepap...s_myth.htm
      Note also who wrote it. Google can help if anyone dosen't know of him.

      Quote:
      --------------------------------------------------------------------------------
      Every set of Brembo O.E. drilled I've seen have developed "stress fractures" (Porsche, Ferrari) around the holes which Brembo has assured Me is only cosmetic damage and does not effect structual integrity.
      --------------------------------------------------------------------------------


      I doubt that Brembo would tell you if it DID! Really, think about it-"yes these brake rotors may fail at a inoppurtune moment, but they look *****in' right?"

      Quote:
      --------------------------------------------------------------------------------
      Baer says the drilling and slotting are for cosmetic purposes only.
      --------------------------------------------------------------------------------


      Agreed, 100%.

      Dan, I'm not trying to be difficult, but most people on this board will, at one time or another, be using their brakes in situations where ANY type of failure will be disasterous. My thought is, why use rotors that WILL crack (Cosmetic? C'mon, a crack is a a FAILURE!) on the most critical system on your car? The aftermarket has bought into this B.S. because it moves parts off the shelves, and at a premium price too.

      Just my (strong) opinion.

      gmachinz
      Unregistered User
      (4/18/04 7:48 pm)
      Reply I thought....?
      --------------------------------------------------------------------------------
      ...this whole discussion peaked several months ago with the consensus that this was just a method tried (unsuccessfully) by racers on road-courses that seen more problems than solutions with regards to braking performance so they went back to solid, vented rotors, right? The reason being (I think) was that rotor diameter and pad compound (and tire choices) were the most important issues to consider and NOT drilled/slotted rotors. -G

      Steve2000SS
      Registered User
      Posts: 263
      (4/20/04 8:19 am)
      Reply DOH!!
      --------------------------------------------------------------------------------
      I guess i was misinformed

      They sure look cast.. i guess its because the holes are radiused (which im sure helps with the cracking).. However i beat the crap out of my old 6 piston Wilwoods and then never develped cracks.. so that should make you feel somewhat better

      Also, the "drilling" on the Wilwoods does not look like a one-pass deal. In other words each side seems to be drilled seperatly and they dont hit the internal vanes.

      If i was building a car for LOTS of racing I would probley steer away from rotors with holes.. but for looks its hard to beat..

      Maybe I will send an email to my guy at Wilwood and ask him to respond in here..

      trouble
      Unregistered User
      (4/20/04 12:39 pm)
      Reply x
      --------------------------------------------------------------------------------
      "To put it in perspective,at Laguna Seca,which is hard on brakes,Rick Mears and I were teamates at Penske and Rick finished the race with only 70 thousandths of an inch of brake pad material left.I only used 70 thousandths of the pad in winning the race.People can brake differently but can still run the same lap time,especially in a race."-Danny Sullivan,quoted from the book ' Going faster'.you can go plenty fast without tearing up your equipment.if you are going through brakes and tires in a(track day) weekend the faulty equipment is located between your ears.that's the hardest part of your car to work on.

      gmachinz
      Unregistered User
      (4/21/04 10:41 am)
      Reply .
      --------------------------------------------------------------------------------
      I like that! Basically it comes down to a common sense approach and an experienced driver to get the combination right, then let the numbers prove which direction you're going in. -G

      walapus
      Registered User
      Posts: 177
      (4/21/04 12:46 pm)
      Reply In answer to Ralph
      --------------------------------------------------------------------------------
      Kt and Kf are "stress concentration factors". For a given change in geometry (a hole) you will have a rise in stress around that change greater than the nominal stress were that hole not present.

      Kt is theoretical. Not all materials react the same to changes in geometry. Cast pieces are usually full of microscopic inclusions, basically built-in stress risers, so the addition of more stress risers is not AS dramatic, depending on what the change is. Kf will therefore be material and situation specific, and is actually calculated from Kt, using another factor q. q is only material specific (me thinks)

      Kf = 1 + q(Kt - 1)



      chicane
      Unregistered User
      (4/21/04 12:50 pm)
      Reply Willwood
      --------------------------------------------------------------------------------
      Steve~ That was the reply I recieved from Willwood on this very subject.....but it would be nice to hear about their specific process, specifically about your observation on the possibility that they drill each side indpendantly.....

      Good question though...

      72SSAbody
      Registered User
      Posts: 62
      (4/22/04 10:57 am)
      Reply .
      --------------------------------------------------------------------------------

      Quote:
      --------------------------------------------------------------------------------
      Kt and Kf are "stress concentration factors". For a given change in geometry (a hole) you will have a rise in stress around that change greater than the nominal stress were that hole not present.

      Kt is theoretical. Not all materials react the same to changes in geometry. Cast pieces are usually full of microscopic inclusions, basically built-in stress risers, so the addition of more stress risers is not AS dramatic, depending on what the change is. Kf will therefore be material and situation specific, and is actually calculated from Kt, using another factor q. q is only material specific (me thinks)

      Kf = 1 + q(Kt - 1)
      --------------------------------------------------------------------------------



      BINGO!

      Sorry, I should have explained myself more when I was posting about the Kt & Kf



      davidpozzi
      Moderator
      Posts: 1092
      (4/23/04 5:52 pm)
      Reply
      Re: .
      --------------------------------------------------------------------------------
      somewhere I saw a photo of a drilled rotor and the holes were almost full of brake pad material. Not much cooling that way.
      David
      67 RS Camaro, 69 Camaro vint racer, 65 Lola T-70 Can-Am vint racer.
      ourworld.compuserve.com/homepages/David_Pozzi/