Announcement

Collapse
No announcement yet.

Running out of crazy ideas to discuss? How about a lighter pumpkin/diff?

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

  • Running out of crazy ideas to discuss? How about a lighter pumpkin/diff?

    So..., In my research of Street Mod rules I'm thinking more creatively.
    The R200 is a solid unit but it's still cast iron/steel and weighs a bunch. Winters makes an aluminum quick change IRS unit but it's $2,900, so that a little too crazy. How about the Ford 8.8" IRS unit? It has an aluminum housing, many diff options, and has to be lighter than the R200. Changing input output flanges wouldn't be too difficult. The real "added cost" would be that you'd still need to swap the ring & pinion, since none of them came over 4:1 stock. What say yee?
    Don Johnson (really!)
    Just so you know.

  • #2
    I think the aluminum Cobra diffs only save a bit of weight off the R200. Like on the order of 10-15 lbs max.

    What about taking an R200 case and then having a machine shop mill down the case some. Just take thickness measurements and a best guess on how much you can shave down. Won't be cheap, but shouldn't be too crazy.

    Or you could just go mad with an angle grinder.
    '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
      Originally posted by Def View Post
      I think the aluminum Cobra diffs only save a bit of weight off the R200. Like on the order of 10-15 lbs max.

      What about taking an R200 case and then having a machine shop mill down the case some. Just take thickness measurements and a best guess on how much you can shave down. Won't be cheap, but shouldn't be too crazy.

      Or you could just go mad with an angle grinder.
      Couldn't case flex become an issue if you're pushing a ton of power and/or torque? I gather a 240 in street mod won't have this "problem" though?

      Comment


      • #4
        How much do those quick change rear ends all the cool drift guys use cost again?

        Or more relevant to this thread, how much do they weigh?
        '95 240sx

        Comment


        • #5
          Def- I'd definitely want to weigh both of them before deciding.

          Bejis- You probably get away with a fair amount of cleanup if you got the time and tools. The main force to be considered is the force that tries to spread the case out when the diff is loaded up. There's also the force trying to push the pinion away from the pinion to consider. You could remove iron from the case and replace it with reinforcement in the aluminum cover. I know for the hot rods they make covers with a big horizontal strut cast in for that purpose. They also make them with bolts in the cover to screw down and put pressure against the bearing caps to make them more stable. I like the way my Dodge 9-1/4" rear sets pre-load. Instead of shims, they have a threaded stop on either side that can be screwed in or out to set lash and pre-load, then locked down.

          Steve- Do you have more info or a link? When I google "quick change differential" I get hits for Winters Performance and for a Torsen Gleason kit that includes parts to make it a "quick change".
          Don Johnson (really!)
          Just so you know.

          Comment


          • #6
            Winters Performance is the place to go for a quick change.

            Watch racingjunk and the GT & circle track racing forums for deals on used equipment. However, many of those guys don't use an IRS so you'd have to modify a used setup.
            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


            • #7
              Can you use a non-Nissan trans? That's probably where you can save way more weight than the diff. Our trans are pretty heavy for what they are, while the diffs are roughly the same weight as most IRS medium sized diffs.

              Now you could look for an R180 out of a Zenki JDM S13. That'd probably save a good bit of weight. There are still some aftermarket diff options for it, but less than the R200.
              '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


              • #8
                Originally posted by Def View Post
                Can you use a non-Nissan trans? That's probably where you can save way more weight than the diff. Our trans are pretty heavy for what they are, while the diffs are roughly the same weight as most IRS medium sized diffs.

                Now you could look for an R180 out of a Zenki JDM S13. That'd probably save a good bit of weight. There are still some aftermarket diff options for it, but less than the R200.
                I don't think I agree regarding the transmission. I can pick up the 5-speed with one hand and carry it around. The automatic can barely be dragged across a greasy painted garage floor it's so heavy. I have a friend running a Z31 300zx with a VG40 and a honkin' big turbo in SSM. He recently spent several thousand on a gearset to fit the F5SW71 5-speed case rather than run the heavier FS5R30A from the Z32 TT.

                I do agree that the R200 isn't much heavier than other similar setups. It's just something I was looking at since it its the single heaviest chuck of iron in the car next to the KA block.

                I followed a discussion about Turbo/V8 Miatas showing that there's only about 10lbs difference between the iron vs aluminum 8.8.

                Move along folks; nothing to see here...,
                Don Johnson (really!)
                Just so you know.

                Comment


                • #9
                  I completely disagree on the trans. I think I weighed mine dry out to about 95 lbs. An E36 BMW ZF box weighs about 55 lbs and can hold just as much torque if not more. I don't think you'll drop 40 lbs off the diff, but you can drop 40 lbs off the trans with some work.


                  I still think you could drop 10 lbs easy off the R200 with some machining. If it splits... oh well, they're cheap to replace. But they've been proven to run 700+ rwhp, so our power levels are barely stressing them. 10 lbs of iron is about 30-35 cubic inches. I think that's doable if you find the areas that are pretty thick and not doing much.
                  '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


                  • #10
                    You'll probably spend less money, and perhaps less time if you just go on a serious cut for a month or two. IDK if you have 40lbs to lose, but it's definitely cheaper than getting super involved with designing a suspension, diff, and/or transmission. I'm sure a lot of us here have at least 10lbs to spare...

                    Comment


                    • #11
                      Originally posted by Beejis60 View Post
                      You'll probably spend less money, and perhaps less time if you just go on a serious cut for a month or two. IDK if you have 40lbs to lose, but it's definitely cheaper than getting super involved with designing a suspension, diff, and/or transmission. I'm sure a lot of us here have at least 10lbs to spare...
                      I'm 5'10" and weigh 155lbs so there's not much to lose.

                      I just weighed a couple of R200 diffs;
                      -open diff and stubs; 72lbs
                      -basic Nismo clutch LSD and stubs; 77 lbs

                      I'll drag out a transmission tomorrow and weigh it.

                      Def- My wife's 330CI is a 5 speed. Are you talking about that one in particular, or in general? That would be a nice weight savings but every BMW I've ever driven have ridiculously short 1st and 2nd gears and hers is the same, and that's with a 2.97 FD. Good info just the same!
                      Don Johnson (really!)
                      Just so you know.

                      Comment


                      • #12
                        I'm 5-10 and only 245 in my race suit. I need to spend more money on lightweight batteries and carbon body panels to get any more weight off the car.

                        buncha little kids... jeez.
                        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


                        • #13
                          Originally posted by djsilver View Post
                          I'm 5'10" and weigh 155lbs so there's not much to lose.

                          I just weighed a couple of R200 diffs;
                          -open diff and stubs; 72lbs
                          -basic Nismo clutch LSD and stubs; 77 lbs

                          I'll drag out a transmission tomorrow and weigh it.

                          Def- My wife's 330CI is a 5 speed. Are you talking about that one in particular, or in general? That would be a nice weight savings but every BMW I've ever driven have ridiculously short 1st and 2nd gears and hers is the same, and that's with a 2.97 FD. Good info just the same!
                          Bunch of scrawny fooks around here....

                          Is the R200 that heavy? I have an extra one in my garage and I carry it around with one hand. Not bragging but I'm pretty strong and constantly train grip strength since I was a strongman competitor (AC arthritis slowing me down now)... But anyway it still only feels to be about 45-50lbs.

                          Originally posted by Matt93SE View Post
                          I'm 5-10 and only 245 in my race suit. I need to spend more money on lightweight batteries and carbon body panels to get any more weight off the car.

                          buncha little kids... jeez.
                          Is the race suit soaking wet when you weigh yourself?

                          Comment


                          • #14
                            Originally posted by Beejis60 View Post
                            Bunch of scrawny fooks around here....

                            Is the R200 that heavy? I have an extra one in my garage and I carry it around with one hand. Not bragging but I'm pretty strong and constantly train grip strength since I was a strongman competitor (AC arthritis slowing me down now)... But anyway it still only feels to be about 45-50lbs.
                            Yes, I am scrawny. The upside is I can eat anything I want and stay there. The only thing I've given up is sweet tea and sodas, because of cholesterol. the doctors said he had good news and bad news. The good news was that my cholesterol was low. The bad news is that it's all the wrong kind!

                            I weighed the diffs with a digital scale!

                            The FS5W71 transmission in the 240sx has a 3.321 first gear and the BMW's run 4.2-4.4 first gear, which is too low.
                            Don Johnson (really!)
                            Just so you know.

                            Comment


                            • #15
                              Originally posted by djsilver View Post
                              I'm 5'10" and weigh 155lbs so there's not much to lose.

                              I just weighed a couple of R200 diffs;
                              -open diff and stubs; 72lbs
                              -basic Nismo clutch LSD and stubs; 77 lbs

                              I'll drag out a transmission tomorrow and weigh it.

                              Def- My wife's 330CI is a 5 speed. Are you talking about that one in particular, or in general? That would be a nice weight savings but every BMW I've ever driven have ridiculously short 1st and 2nd gears and hers is the same, and that's with a 2.97 FD. Good info just the same!
                              Any of the later E36/E46 5 speed trans are that light. It's RIDICULOUS how small and light they are compared to a Nissan trans. I was expecting something about like that when I did my first S13 clutch job... holy crap, I about shart myself when I was expecting 55 lbs and got more like 95 lbs.

                              Here's how small they are, that's not an optical illusion:




                              They have a 1:1 5th gear, so something like a 3.69 is going to give fairly short gearing, and a 3.96 gives super short gearing. I never thought their gearing with the <3:1 rear end ratios was that short. I thought it was reasonable with the 3.23 and 245/40-17's in my E36 M3s.
                              '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

                              Working...
                              X