Announcement

Collapse
No announcement yet.

Butcher Crank

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Butcher Crank

    I'm building a new engine for my car and have been searching for info on SR's running a butcher crank. Doesn't seen like its used here like in the DSM world.
    Anyone have any experience with one in a SR?
    SR crank are crazy heavy


    http://www.ffwdconnection.com/butchercrank.html
    98 240sx w/ S15 SR20DET, TD06 20g, FMIC, 3in exhuast, walbro, EBC,

  • #2
    I've seen that done before (aero profiling the counterweights) - it makes sense, but I guess it depends on the cost as to whether it's worth it. SR cranks are super heavy...
    '18 Chevrolet Volt - Electric fun hatch for DD duty!


    DefSport Koni Sleeve and Spring Perch Buy!!!
    http://www.nissanroadracing.com/showthread.php?t=5902

    Comment


    • #3
      BTW - wouldn't you need to balance things with the correct bob weights of your reciprocating components?
      '18 Chevrolet Volt - Electric fun hatch for DD duty!


      DefSport Koni Sleeve and Spring Perch Buy!!!
      http://www.nissanroadracing.com/showthread.php?t=5902

      Comment


      • #4
        I believe it runs $550-600 and they balance it to .1 ounce/inch tolerance. Pretty sure that's better balance than factory.

        People have been using them in the dsm world for 10+ years. DSM crank don't start out nearly as heavy. Surprises me I can't really find any info on them in SR world.
        98 240sx w/ S15 SR20DET, TD06 20g, FMIC, 3in exhuast, walbro, EBC,

        Comment


        • #5
          How can you balance something with less than half the bits that rotate around? Yea, for one piston/rod going down, there's another going up, but a balance with bob weights will be different than one without.
          '18 Chevrolet Volt - Electric fun hatch for DD duty!


          DefSport Koni Sleeve and Spring Perch Buy!!!
          http://www.nissanroadracing.com/showthread.php?t=5902

          Comment


          • #6
            Are you talking about balancing the crank or the whole assembly?
            98 240sx w/ S15 SR20DET, TD06 20g, FMIC, 3in exhuast, walbro, EBC,

            Comment


            • #7
              Cost is $680 with the Vader coating.
              98 240sx w/ S15 SR20DET, TD06 20g, FMIC, 3in exhuast, walbro, EBC,

              Comment


              • #8
                as long as you balance the whole thing, have at it. not real sure it's worth the cost unless you're really reaching for that last 3hp..
                Originally posted by SoSideways
                I don't care what color they are as long as they are LONG AND HARD.
                '04 G35 Sedan 6MT- The DD
                '96 240SX- The Track Toy

                Comment


                • #9
                  It's not a V engine. As long as rods and pistons are weight matched I see no need to spin balance them with the crank.

                  Where do you come up with the 3hp gain number? I would think the benefits are more than just hp related. Was hoping there may be some here with actual experience with one in a SR.
                  98 240sx w/ S15 SR20DET, TD06 20g, FMIC, 3in exhuast, walbro, EBC,

                  Comment


                  • #10
                    Why not just get a much lighter clutch/flywheel combo for cheaper? Way less inertia if that's what you're going for.

                    I'd be really surprised if the aero profiling makes more than a few HP difference. That's A LOT of aero drag on something as compact as a crank.
                    '18 Chevrolet Volt - Electric fun hatch for DD duty!


                    DefSport Koni Sleeve and Spring Perch Buy!!!
                    http://www.nissanroadracing.com/showthread.php?t=5902

                    Comment


                    • #11
                      Originally posted by tom n View Post
                      Was hoping there may be some here with actual experience with one in a SR.
                      Good luck with that. On any forum. Way too many poseurs out there that talk a lot, and the smart ones stay quiet. With posts like this, you're likely not going to get much help.
                      Originally posted by SoSideways
                      I don't care what color they are as long as they are LONG AND HARD.
                      '04 G35 Sedan 6MT- The DD
                      '96 240SX- The Track Toy

                      Comment


                      • #12
                        Originally posted by Def View Post
                        Why not just get a much lighter clutch/flywheel combo for cheaper? Way less inertia if that's what you're going for.

                        I'd be really surprised if the aero profiling makes more than a few HP difference. That's A LOT of aero drag on something as compact as a crank.
                        Already have a lightened flywheel. Clutch is a Silk Road set up. Not sure the weight of it.

                        The benefits I would think are not just about HP gains. Being knife edged it would certainly not churn the oil up as much. It would slice right thought it.



                        Originally posted by Matt93SE View Post
                        Good luck with that. On any forum. Way too many poseurs out there that talk a lot, and the smart ones stay quiet. With posts like this, you're likely not going to get much help.
                        Sadly that's all to often true.
                        98 240sx w/ S15 SR20DET, TD06 20g, FMIC, 3in exhuast, walbro, EBC,

                        Comment


                        • #13
                          I mean a really low inertia setup like a 7.25 or 5.5" clutch setup.

                          There will be a little less frothing of the oil, but I doubt it's that much.

                          Isn't this something you could do with a few hours of time on a die grinder and then get it balanced locally later?
                          '18 Chevrolet Volt - Electric fun hatch for DD duty!


                          DefSport Koni Sleeve and Spring Perch Buy!!!
                          http://www.nissanroadracing.com/showthread.php?t=5902

                          Comment


                          • #14
                            What's a good 7.25 set up that's street friendly for a SR20?
                            And can handle 450-500 TQ.
                            98 240sx w/ S15 SR20DET, TD06 20g, FMIC, 3in exhuast, walbro, EBC,

                            Comment


                            • #15
                              Originally posted by tom n View Post
                              What's a good 7.25 set up that's street friendly for a SR20?
                              And can handle 450-500 TQ.
                              Street friendly and ultralight drivetrain are mutually exclusive.
                              Originally posted by SoSideways
                              I don't care what color they are as long as they are LONG AND HARD.
                              '04 G35 Sedan 6MT- The DD
                              '96 240SX- The Track Toy

                              Comment

                              Working...
                              X