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  • #31
    Re: Brakes upgrade

    Originally posted by 10gt61 View Post
    Thinking DBA 4000 all round.
    I used DBA 4000 this year and had no complaints. I avoid the OEM rotors as they cost a fortune compared to aftermarket

    For pads, using PF11s, and they are great
    sigpic
    _________________
    Carsten - OTA #276 GT1

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    • #32
      Re: Brakes upgrade

      Originally posted by nissannx View Post
      Better stopping power. Better getting out of corner power. Better constant power. Should be good!
      Sounds good!
      Saw your name on the Carbotech website.
      Nice.
      Kelly B. GT Class Competitor 2011 - 2014
      OTA Director 2015
      ASN/FIA Committee 2015

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      • #33
        Re: Brakes upgrade

        Originally posted by IWannaGoFast View Post
        I used DBA 4000 this year and had no complaints.
        If you like 'em, I like 'em.
        Must be similar weight cars?
        Kelly B. GT Class Competitor 2011 - 2014
        OTA Director 2015
        ASN/FIA Committee 2015

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        • #34
          Re: Brakes upgrade

          Originally posted by 10gt61 View Post
          Must be similar weight cars?
          Close, prob. a 200lbs difference
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          _________________
          Carsten - OTA #276 GT1

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          • #35
            Re: Brakes upgrade

            Originally posted by 10gt61 View Post
            Good to know - thx. CT also says I can go XP12 or XP20.
            Do need to resurface rotors or get new ones though (according to website).
            Thinking DBA 4000 all round.
            What year is your 'stang, and does it have the 'brembo' brake package?

            I would stay away from the DBAs, not that they are not a good product but just not worth the extra cost over a high quality stock replacement. I ran cheapie Centric rotors on my vette for two years (20+ events) with no issues and when I finally replaced them it was due to rotor wear and not cracking. While the Centrics are a a low cost option they are a quality product, well made and well finished. I got fancy slotted two piece rotors with my AP racing kit, which have now cracked (insert unimpressed face). I'll be looking to replace with OEM blanks.

            From the tirerack;

            Centric (made by Stoptech) plain rotors:
            per Front: $79
            Rear: $38
            Total: $234

            DBA 4000
            per Front: $162
            Rear: $166
            Total: $656

            I'm sure the DBAs are well made, but no way they are 280% better.
            Greg.

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            • #36
              Re: Brakes upgrade

              I have a set of front DBA 4000 rotors for my 'vette but when looking closely at them , they have a significantly different hat portion than the OEM or other aftermarket rotors (at least in my application). It should prevent some of the asymmetrical expansion of the rotor with heat which no doubt leads to cracking but they look like they will hinder air flow through the rotor, not benefit it. For this reason, I haven't used them on the track and just the street.

              OTOH, they do appear to be a better quality casting.

              BTW Kelly, I have used both Carbotech 10s and 12s up front and found the 12s to be a bit more twitchy buy not bad and absolutely streetable. Wear is a bit faster than I would have hoped. As for fade, not bad and given that even though Corvettes are lighter than Mustangs, they are so much faster and given that the heat production is (I think) proportional to the square of the speed, the total number of BTUs that need to be shed is similar in our 2 cars. ( I could be wrong about the heat being made being proportional to the square of the speed delta but I'm sure someone with more physics background can chime in)
              Mobil 1 Time-Attack # 4, CCC Member

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              • #37
                Re: Brakes upgrade

                Originally posted by Greg Campbell View Post
                What year is your 'stang, and does it have the 'brembo' brake package?

                While the Centrics are a a low cost option they are a quality product, well made and well finished.
                2010 GT. No Brembo.
                Centrics worth considering.
                Kelly B. GT Class Competitor 2011 - 2014
                OTA Director 2015
                ASN/FIA Committee 2015

                Comment


                • #38
                  Re: Brakes upgrade

                  Originally posted by Dave Barker View Post
                  As for fade, not bad and given that even though Corvettes are lighter than Mustangs, they are so much faster
                  Ahh Dave. I can see your smiling face when you typed that sentence.
                  I'll edit for you: even though some corvettes are faster than some mustangs.
                  There, that's better.
                  Kelly B. GT Class Competitor 2011 - 2014
                  OTA Director 2015
                  ASN/FIA Committee 2015

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                  • #39
                    Re: Brakes upgrade

                    Originally posted by 10gt61 View Post
                    2010 GT. No Brembo.
                    Centrics worth considering.
                    JRP carries the Centrics so now you can buy them at a discount as well. If you decide to go that route talk to me first.
                    Chuck Atkins

                    Ontario 1500 Motorsport Adventure Organizer
                    Former CASC-OR Ontario Time Attack Director
                    Former ASN Canada FIA SoloSport Ontario Rep

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                    • #40
                      Re: Brakes upgrade

                      Originally posted by Greg Campbell View Post
                      For what it's worth, here's my 2 cents.

                      A larger diameter rotor will have a greater moment of inertia so unless you are going with carbon rotors the reduction in mass will not offset the increased diameter.
                      Hmmm - just for argument sake, not sure I agree. Trying to remember my basic physics. Pretty sure it's the mass that really matters. I believe a larger diameter rotor with less mass than a smaller diameter rotor with more mass would still be beneficial, notwithstanding the inertia. Think of a 15" rotor made of tin vs. an 8" rotor made of lead. Extreme example, I know, but demonstrates the point I think? Of course, I stand to be corrected.

                      Not that it really matters Pretty sure I'm going with less expensive new 1 piece rotors all round and step up a notch or two with the brake pads.
                      Kelly B. GT Class Competitor 2011 - 2014
                      OTA Director 2015
                      ASN/FIA Committee 2015

                      Comment


                      • #41
                        Re: Brakes upgrade

                        Originally posted by 10gt61 View Post
                        Hmmm - just for argument sake, not sure I agree. Trying to remember my basic physics. Pretty sure it's the mass that really matters. I believe a larger diameter rotor with less mass than a smaller diameter rotor with more mass would still be beneficial, notwithstanding the inertia. Think of a 15" rotor made of tin vs. an 8" rotor made of lead. Extreme example, I know, but demonstrates the point I think? Of course, I stand to be corrected.

                        Not that it really matters Pretty sure I'm going with less expensive new 1 piece rotors all round and step up a notch or two with the brake pads.
                        The disc inertia formula is I = 1/2 M x R(2). Lets use an example;

                        V8 Mustang rotors (centric parts) are 20.05 lbs and 12.43 inches in diameter. Converted into 21st century measurements is 9.09kg and 0.316 meters. Moment of inertia is 0.113kgm2.

                        If you upgraded to 14" rotors (0.356 m) in order to maintain the same moment of inertia the rotors would need to weigh 7.16kg; a 2 kg reduction just to maintain the same performance. If you were looking to improve rotational performance you would need to reduce mass more than 2 kg.

                        This phenomenon is the same as the out-sized performance gain people experience when going to smaller diameter wheels and why you don't see 'dubs on the track.

                        Now, this calculation is imperfect since the formula assumes a consistent distribution of mass across the radius of the disc, a larger disc would probably have the friction surface moved farther out so the distribution of weight across the face of the disc would change.
                        Last edited by Greg Campbell; 11-09-2014, 06:42 PM.
                        Greg.

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                        • #42
                          Re: Brakes upgrade

                          Originally posted by Greg Campbell View Post
                          The disc inertia formula is I = 1/2 M x R(2). Lets use an example;

                          V8 Mustang rotors (centric parts) are 20.05 lbs and 12.43 inches in diameter. Converted into 21st century measurements is 9.09kg and 0.316 meters. Moment of inertia is 0.113kgm2.

                          If you upgraded to 14" rotors (0.356 m) in order to maintain the same moment of inertia the rotors would need to weigh 7.16kg; a 2 kg reduction just to maintain the same performance. If you were looking to improve rotational performance you would need to reduce mass more than 2 kg.

                          This phenomenon is the same as the out-sized performance gain people experience when going to smaller diameter wheels and why you don't see 'dubs on the track.

                          Now, this calculation is imperfect since the formula assumes a consistent distribution of mass across the radius of the disc, a larger disc would probably have the friction surface moved farther out so the distribution of weight across the face of the disc would change.
                          Interesting stuff - love it. Thx Greg!
                          Kelly B. GT Class Competitor 2011 - 2014
                          OTA Director 2015
                          ASN/FIA Committee 2015

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                          • #43
                            Re: Brakes upgrade

                            What are the formulas for dissipation of heat on an increased surface area?

                            Through vented aluminum hats instead of steel?

                            Is the vaned rotor of larger diameter venting more air and achieving more cooling?

                            Does going to a larger swept area of the pad (e.g.: 6 piston calipers) allow greater friction for a shorter braking period if above the lockup point of the tire? Therefore allowing longer periods of acceleration?

                            Then you get into the fuzzy less quantifiable effects upon a driver of having solid brakes that aren't inconsistent.

                            Granted, going too high outside an OE diameter with a two piece may not have inertia yields, but the net effect upon laptime can still improve.
                            sigpic

                            Stephen, SPDA VP, OTA Director, CCC Member
                            OTA: SGT1 ! -=- CSCS: SSA #842

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