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#1. Re: [E36M3] More on brake pads and rotors - from Ken Robb
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Date: Thu, 06 Apr 2000 17:18:40 -0700 From: Ken Robb <kenrobb@willisallen.com> Subject: Re: [E36M3] More on brake pads and rotors that"less time on the brakes" sounds like a good explanation. Ron Katona wrote: > Date: Thu, 06 Apr 2000 19:32:00 -0400 > From: Ron Katona <rkatona@bellatlantic.net> > Subject: Re: [E36M3] More on brake pads and rotors > > Sean Hester wrote: > > it's obviously not perfect. track pads DO heat some. and it's IS possible > > to warp rotors even with track pads. but the fact that they don't heat up > > as much and cool alot faster goes a long way to not warping rotors. > > I think that's exactly right, but there's another problem compounding > things. As the non-track pads heat up, they don't stop as well. That > means you have to back up your braking points and brake longer. That > adds yet more heat to the process which is tougher on the rest of your > brake components and continues the cycle towards warped rotors, melted > caliper seals, boiled fluid, and no brakes at all unless you slow down > and conserve the brakes. > > The track pads remain highly effective and therefore allow you to keep > your braking to short distances. I'm in the camp of "it's not how hard > you brake, but for how long" that determines the amount of stress on the > whole brake system. Less time on the brakes = more time to cool = fewer > warped rotors. > -- > Ron Katona > > ************************************************************* > List Commands > UNSUBSCRIBE - (in subject line) unsubscribes you from the mailing list. > ************************************************************* -- ----------------------------------------------------- Click here for Free Video!! http://www.gohip.com/freevideo/
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#2. Re: [E36M3] funny cold start sound - from Mdriver13@aol.com
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Date: Thu, 6 Apr 2000 20:35:18 EDT From: Mdriver13@aol.com Subject: Re: [E36M3] funny cold start sound This will happen to any of the E36M3's at least through production year 1997. It's the Ferrari starter. It sticks for a second or two during cold weather. I've lived with it for four winters, no starting problems yet. Just talked to my BMW mechanic on Tuesday, he said the last one he replaced (last week), actually fit better than the other replacement starters. He tells me the replacements are BMW made, and that's the problem. Up until now the replacement was a "bitch" to bolt on (I have heard of these starters dropping to the ground!!), and not a perfect match compared to the OEM starter. Good luck. Bob Gill 97 ///M3 coupe Philly Region SCCA 1st AS - '97 2nd AS - '98 & '99
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#3. Why track pads don't warp rotors - from Michael Lord
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Date: Thu, 06 Apr 2000 17:45:19 -0800 From: "Michael Lord" <michaellord@uswest.net> Subject: Why track pads don't warp rotors >From: "Ken Robb" <kenrobb@willisallen.com> >Subject: Re: [E36M3] More on brake pads and rotors >I know that track pads are more resistant to fading but I am unaware that they >do anything to reduce warping. They remain effective at higher operating temps >than stock which implies that they are running at higher temps which would have >caused fading in the stock pads. If this is true then why wouldn't the rotors >get as hot or hotter than when used with stock pads? I am making some educated guess's here but I'll give this a shot. First, I have always been told that track pads will run a bit cooler than stock pads. I don't know why this would be so but it is what I have always been told was true. This might be a good question for someone at Porterfield. In my own experience, the last set of rotors I ever warped was using the Porterfield R4's instead of my usual PF90's. I don't remember if I concluded on my own, or if I was told, or both, that this was because the R4's run a bit hotter than the PF90's. It is, however, one of the reasons I do not run the R4's anymore. I think a second reason that track pads prevent warped rotors is precisely because they don't fade. If brakes are not fading then you don't need to stay on them as long to stop the car. If you don't need to stay on them as long they will run cooler. If they run cooler they will be less prone to warp rotors. >I think the biggest factor >in reducing warped stock rotors is a good cool-down lap and, as someone said >here recently, possibly driving slowly around the paddock or perimeter road >after your cool-down lap. I would have to agree that the best way of preventing warped rotors is a good cool down lap. However, I know from experience that it is possible to get the brakes so hot that the best cool down lap in the world will not save them. One last item that seldom gets mentioned is standing water. Do not drive through mud puddles or any kind of standing water on hot brakes. They will warp instantly. BTW, I received a very well thought out private response from Bryan Watts the other day regarding my "go faster" response to his claim that he never warps rotors. It occurred to me that it has been a very long time since I have warped any rotors *or* driven on stock M3 brakes long enough to get them to fade significantly. As such I can no longer say with certainty whether or not it is possible to drive quickly on a track with stock brakes for a whole days lapping and not warp your rotors. I don't think so but I could be wrong (though I doubt it). I started using track pads, rotors, fluid, etc. long before my brake technique was sorted out. While this set up did, for the most part, bring an end to warped rotors in spite of shoddy brake technique, it was attention to brake technique that banished it forever (I hope). So, in the name of research, is there any one out there who wants to loan me their stock braked, M3 for a day of lapping so I can find out? For the good of us all, of course! ;-) My $0.02 Michael Lord
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#4. Denver area shop needed - from Steve Grigory
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Date: Thu, 6 Apr 2000 18:07:04 -0700 (PDT) From: Steve Grigory <grigory@opentrack.eng.sun.com> Subject: Denver area shop needed Hi, I have a "not on this digest yet" buddy in Denver who is looking for a good shop to install a DaLan hitch on his 95 M3... The trunk requires reinforcement (the primary use will be hauling mountain bikes around) and his concern is finding a shop that will do the installation correctly. Please contact him directly at: BHilton@rhythms.net Thanks! steve
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#5. Re: [E36M3] Speeding ticket avoidance (guaranteed) - from JimShadow@aol.com
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Date: Thu, 6 Apr 2000 22:08:26 EDT From: JimShadow@aol.com Subject: Re: [E36M3] Speeding ticket avoidance (guaranteed) John, I couldn't agree with you more!! Basically what it comes down to is this: If you are going to speed, then you'd better be prepared to pay the price. If there is an easy way out of it, then great. If not, then don't whine about it, after all the cop was just doing the job WE pay him to do when YOU got caught. JimShadow (Looked like there was a little room up on John's soapbox.....:)
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#6. Re: [E36M3] More on brake pads and rotors - from Sean Hester
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Date: Thu, 06 Apr 2000 19:35:10 PDT From: "Sean Hester" <seanh_race@hotmail.com> Subject: Re: [E36M3] More on brake pads and rotors >I think that brakes are just energy converters that change the energy of a >moving car into heat. I doubt that track pads can do this without getting >the >rotors as hot as stock pads. I can see that carbon fiber might dissipate >the >heat quicker but still we are talking about how hot the rotors get and not >about >transferring heat from the pad to the caliper and brake fluid. I think we >all >agree that most track pads don't even work at their best until they get >warmed >up. BTW I thought we were talking about track pads [a loosely defined term] >some >of which are carbon fiber and some are not. What little I know about >physics >suggests that if the rotors don't GET hot there was no conversion of >kinetic >energy to heat and the car isn't slowed. The trick is to get rid of the >heat as >rapidly as possible through vents,ducts, etc. There must be some other >thoughts >out there guys. race pads do not lower the temp of your rotors under braking. i don't think i said that, but if it was taken that way i'm sorry, i wrote that message in a hurry (since i told people to e-mail me for a longer version) but now i'm home and will write a longer version that you can ignore if you're not interested. here goes... what race pads DO do is stay cooler THEMSELVES, which exposes the rotors to less heat overall, which lowers the temp of the rotors in the LONG run. the temp of the rotor DURING a stop is largely unaffected. (it is affected a little as explained below). let's say you stop your car with the brakes. that generates a certain amount of heat based on the mass of your car, and the differential in speeds, and how long the braking was. the heat generated in that stop is constant no matter what pads you use. so now... you have a bunch of stuff exposed to that heat. rotors, pads, calipers, etc. and things exposed to heat, gain temperature right? but how much temp do they gain when exposed to that heat? if you put an iron rod and an aluminum rod and a carbon fiber rod (all at the same temp) into a fire for 20 seconds then take them out, are they all the same temp? NOOO!!!! the iron rod has heated up alot more then the alum rod, and the carbon fiber rod hasn't heated much at all. that property of materials (how much the temp changes when exposed to heat) is called specific heat. and the specific heat of race pads is higher (meaning it takes more hear to raise their temp, meaning when exposed to the same heat for the same time, they raise in temp LESS) now... as the temp of the brake system rises the brake parts themselves become radiators of heat. so when you get to braking zone #2 not only do you have the heat generated by the stopping, but you have the heat generated by the fact that the brake parts are already hot, and raidiating that heat. SO. if you can manage to keep the brake pads themselves from heating up you can LOWER the amount of total heat that the rotors are exposed to. (that amount of heat radiated by the pads is small compared to the new heat generated by the stop, but is all adds up!!!) cooling is also effected by the heat maintained by stock pads. heat is shed by differences in temperature. if the rotors (hot) are sitting next to pads of the same tempersture, not much cooling is going to happen. but again, if the pads are cooler then that will help the rotors cool down alot faster. that's the way that race pads help keep rotors cool. and it IS all about cooling. the heat is generated no matter what. it's all about not holding the heat, and getting rid of what you do hold. it IS TRUE that ducting and other methods to get more airflow to the brakes has more of (or at least as much as) an effect on rotor warping. a car with great ducting and stock pads is probably better off then a car with no ducting and track pads. but both have a HUGE effect and race cars use BOTH to save their rotors. so... YES track pads help keep your rotors cool. does it help as much as ducting? no. (but almost) but here's the real question. which is easier to do to your E36 M3? pads or ducting? and the answer is, PADS PADS PADS PADS. between myself, turner motorsport, and 4 local seattle race shops, no one has come up with a good reliable method to get fully hub ducted brakes. (the stage 1 things with a tube pointing at the caliper help MUCH less then hub mounted systems) i have brake ducts on my M3. they are a pain to get in. a pain to maintain (i get holes about onec a month) and expensive. do they work? heck yeah. but they don't work much better then the track pads. i drive in such a way that i need both. but i'll bet 95% of M3 drivers only need one cooling method. and i'd tell them ALL to try pads first, to see if it's enough. and if it's not (unlikely) then they have to get some ducting. ______________________________________________________ Get Your Private, Free Email at http://www.hotmail.com
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#7. Re: [E36M3] Why track pads don't warp rotors - from Sean Hester
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Date: Thu, 06 Apr 2000 19:48:48 PDT From: "Sean Hester" <seanh_race@hotmail.com> Subject: Re: [E36M3] Why track pads don't warp rotors >I think a second reason that track pads prevent warped rotors is precisely >because they don't fade. If brakes are not fading then you don't need to >stay on them as long to stop the car. If you don't need to stay on them as >long they will run cooler. If they run cooler they will be less prone to >warp rotors. this is also true. i hardly ever got stock brakes to fade, so i tend to forget about this, but it matters alot. the longer you stay on the brakes, because of fading (or not), the more heat you're going to get building up. another problem you can get with fade is having the ABS kick on as you panic and press the brake pedal as hard as you can. while noone has figured out the exact physics, lots of us have proven emperically, that constant prolonged use of ABS is a sure fire way to warp rotors on an E36 M3. > >I think the biggest factor > >in reducing warped stock rotors is a good cool-down lap and, as someone >said > >here recently, possibly driving slowly around the paddock or perimeter >road > >after your cool-down lap. i'd be willing to bet that 90% of rotors are warped in the pits after you park your car. think about it. your car is parked with hot brakes. one spot on your rotor is kept hot (it's sitting next to a hot pad) while the rest cools. you couldn't ask for a better way to warp rotors if you tried. again, track pads can help here (they don't get as hot in the first place, and they cool faster) but you still have to cool them down. i take a cooldown lap with NO BRAKES at all. that means i'm going pretty darn slow, so it takes a while. all the better for cooling, even though people are about to rear end you as they want to get off the track, show off to their friends, and warp a rotor. but it's worth it. and i also drive around the paddock a bit. when you get out of your car, put your head next to the front wheel. if you can hear the metal making ticking noises (or if you can feel heat on your face) get back in and drive around some more. ______________________________________________________ Get Your Private, Free Email at http://www.hotmail.com
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#8. Rear end squeak continues... - from Andy Korczynski
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Date: Fri, 7 Apr 2000 09:00:28 -0500 From: Andy Korczynski <Andy@casskor.com> Subject: Rear end squeak continues... A couple people suggested it may be the seats and i lowered them on the way in today and the squeak got louder. Obviously the seats were muffling the sound a good amount, and it now sounds like for sure its the passenger side that is the culprit. Again, recapping, its a 99 m3 (no suspension mods other then an x brace) with about 8k on it and it makes this squeak on every bump (i can hear it better with the seats down) and its usually a double or triple squeak, squeak, squeak so I'm thinking its gotta be something with the shock. Any ideas? Andy K.
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#9. [E36M3] More on brake pads and rotors - from Eric.C.Dotson@travelers.com
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Date: Fri, 7 Apr 2000 10:29:23 -0400 From: Eric.C.Dotson@travelers.com Subject: [E36M3] More on brake pads and rotors >>>I think that brakes are just energy converters that change the energy of a moving car into heat. I doubt that track pads can do this without getting the rotors as hot as stock pads. I can see that carbon fiber might dissipate the heat quicker but still we are talking about how hot the rotors get and not about transferring heat from the pad to the caliper and brake fluid. I think we all agree that most track pads don't even work at their best until they get warmed up. BTW I thought we were talking about track pads [a loosely defined term] some of which are carbon fiber and some are not. What little I know about physics suggests that if the rotors don't GET hot there was no conversion of kinetic energy to heat and the car isn't slowed. The trick is to get rid of the heat as rapidly as possible through vents,ducts, etc. There must be some other thoughts out there guys. Ken Robb<<< I agree with Ken here. My understanding has been that a "race" brake pad is one that can maintain it's coefficient of friction at the high temperatures generated by track use. These pad materials may be able to dissapate heat faster than stock pads, but the majority of the heat is going to be absorbed by the component with the most mass - the rotor. A big cast iron brake rotor is going to be able to absorb more heat than the pads, calipers, fluid, or anything else in the braking system. This ability of cast iron to absorb heat is why it us used for rotors, exhaust manifolds, etc. The braking system works by converting the energy used to turn the rotor (and the wheels and tires, thus moving the car along) into heat. The heat is generated by the friction between the brake pad and brake rotor, simple as that. Now, if we have a pad that can maintain coefficient of friction and therefore it's stopping power at higher temps, then the same amount of friction is generated at these higher temps. For argument's sake, suppose the stock pad maintains a constant c.o.f. from 0-500 degrees. At 600 degrees, it cannot maintain the same c.o.f. due to the excess heat, so the friction decreases, and you get brake fade. But even though the level of friction is dropping, you are still transferring heat into the rotor. Now take a racing pad, let's say it maintains the same c.o.f. from 500-1000 degrees. Now you're maintaining the same level of friction at twice the temperature. Your rotor is at 1000 degrees, and the racing pad allows you to maintain stopping power at that temperature where the stock pads would have long been toast. Now your rotors are glowing along at 1000 degrees (and you can still stop the car), so I don't see how a racing pad could allow lower temperatures in the braking system. Ken is right, less heat = less friction = less stopping power. I'm sure there are plenty of factors I'm leaving out, but this is a simple explaination. Eric 95 M3 95 325i
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#10. FYI: New '99 M Coupe Available - from Landrum, Jared
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Date: Fri, 07 Apr 2000 09:43:11 -0500 From: "Landrum, Jared" <landrum@lafayette.dowell.slb.com> Subject: FYI: New '99 M Coupe Available FYI: I noticed that my local dealer has a new '99 M Coupe on their lot that they've dropped the price on. I guess these Cajuns aren't crazy about the styling of this car. Anyway, all I know is that it is black on black and has a MSRP of $43,670. The dealer is currently asking $34,500. If anyone is interested, it is located at Moss Motors in Lafayette, LA. Their web site is: http://www.mossisboss.com/ Regards, Jared Landrum