getZ Posted July 19, 2007 Share Posted July 19, 2007 Work was boring, waiting on some other tools to come back up so I start looking for information on 280z stub axle since I want to upgrade to CV's and I found this picture of the two side by side. I can't validate the correctness of the dimensions but if they have the same thread size, what the advantage of using the 280z stub axle? The two pictures I have seen of broken axles have both axles broken off at exactly the same place, where the thread ends and the spline begins. My thoughts being "what is the advantage of the greater spline count if that is not the weak point?" It's the same size everywhere else. The article said 240z axles will break in other places, but can sombody shed a little more light on this, like where they break? I can understand why Rosses stuff is so much stronger, but not why a 280z stub axle would be stronger 240z stub axle. Do the later axles have a better tempering or shot peening? This is the site I was looking at (I believe a fellow hybridz member): http://www.magshooterz.com/280z_stub_axle_swap.htm Quote Link to comment Share on other sites More sharing options...
getZ Posted July 19, 2007 Author Share Posted July 19, 2007 I made a mistake earlier about two pictures of broken axles being at the same point. After looking at JBC3's broken axle I think I understand what happens. The axle starts to distort and the splines jump out of groove while pulling away from the companion flange. A larger spline count keep it from twisting out and putting pressure on the threaded part. Quote Link to comment Share on other sites More sharing options...
Pop N Wood Posted July 20, 2007 Share Posted July 20, 2007 The FAQ page has some stub axle failure pictures http://forums.hybridz.org/showthread.php?t=116207 The 280 axle is a larger diameter right at the base of the threads than the 240 axles. There is a much better picture floating around the web showing more precise dimensions on the two axles. It use to be on Eric Neyerlin's site, but I can't find it anymore. You might be able to find it searching this site. Quote Link to comment Share on other sites More sharing options...
getZ Posted July 20, 2007 Author Share Posted July 20, 2007 A flange breaking is down right scary. Even with disc brakes it looks like you could see your wheel rolling right past you. The one in the picture from the sticky looks like it broke from a hard sideways hit not a 1.3 second 60 foot time. I guess I'm more concerned about drag racing stuff, because that's what my car is set up to do. I keep going back and forth with this, but I keep going back to my original thinking that the weak point is the taper going to the threads and not the spline. The axle twists under hard acceleration and actualy starts to shorten it's length due to twisting, putting a lot of strain on the nut. I think I will call moser or one of the other racing axle manufacturers and ask what they think since I'm sure they have seen it all with axle breakage. Quote Link to comment Share on other sites More sharing options...
Pop N Wood Posted July 20, 2007 Share Posted July 20, 2007 I keep going back and forth with this, but I keep going back to my original thinking that the weak point is the taper going to the threads and not the spline. From the number of failed stubs I have seen on here I tend to agree with you. and from this link you can see that getting rid of the taper moves the weak point to the splined area itself Quote Link to comment Share on other sites More sharing options...
getZ Posted July 20, 2007 Author Share Posted July 20, 2007 I'm thinking, as the axle starts to twist, it starts to bow. A weaker axle would break immediately because it cannot stretch. The billet axle will stretch until the spline starts to come out of the companion flange, then it breaks. I can't see a spline breaking inside the flange where the flange is surrounding the spline Of course, if you have enough power and traction you can break anything, but I was thinking if there was another bearing between the two it would keep the axle from bowing. I dunno, it was just a thought. I'm really looking for another solution besides after market axles, but in the end I will probably install a set of billeted axles anyway. I don't have enough power or traction to break a billet axle and MMS axles are a straight "bolt in". Quote Link to comment Share on other sites More sharing options...
getZ Posted July 22, 2007 Author Share Posted July 22, 2007 I decided this is an excercise in futility, at least for me. You can fab something up, but you won't save any money, unless you have access to a full machine shop. If your track is like mines where you get kicked off the track for having an indepent rear end running sub 11's (I'm not that fast, but that is the track rule), there is no point in having an absolutely bullet proof indepent rear suspension that can handle 500 horsepower. Quote Link to comment Share on other sites More sharing options...
johnc Posted July 22, 2007 Share Posted July 22, 2007 there is no point in having an absolutely bullet proof indepent rear suspension that can handle 500 horsepower There is no such thing anyway. Quote Link to comment Share on other sites More sharing options...
getZ Posted July 23, 2007 Author Share Posted July 23, 2007 Very stout IRS setups. I didn't realize that IRS suspension could be legal for faster than 10 second quarters...isn't the internet awesome? I've seen an aritcle on a 8 sec IRS viper once upon a time as well. http://www.hotrod.com/techarticles/113_0502_1963_1979_corvette_irs_buildup/index.html Quote Link to comment Share on other sites More sharing options...
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