Mikelly Posted June 20, 2007 Share Posted June 20, 2007 I totally agree, and I for one appreciate news hitting the board first, in it's un-edited purity. Obviously such happenings would be better for business taken off line, but I don't think that's in the spirit of the board (I could be wrong). Being an enthusiast, while I do care if it's the best product out there, I care even more if there's been a documented breakage. We all like making informed decisions, isn't that what sites like this are all about? Hopefully others won't feel as if they shouldn't speak up about product limitations... Absolutely... This has NOTHING to do with Ross or MML, other than the fact that he sold the part... That's it... It's good for the community, and for Ross... It'll help him develop a solution that will be stronger in the long run. For people to get their panties in a bunch, and run off and drop a dime is just plain SAD on so many levels... The spin is that there was NO BASHING of the company or product... Had there been any, I'd be the first to defend the vendor, but this is simply NOT the case... Jody and Ross, Keep us posted on future developments for the stubaxles... We're all ears... As to anyone wondering about who I shop with. I always visit Ross' page FIRST before I look to other vendors for support... So it's not like I don't "support" Ross and his efforts. Mike Quote Link to comment Share on other sites More sharing options...
danj Posted June 23, 2007 Share Posted June 23, 2007 I am very interested in the outcome of this thread since I am in the process of putting together a plan for getting the power to the pavement in my 83 ZX. I'm running about 500 HP NA (Edelbrock calculation) on my 383 stroker with aggressive Comp cam and Pro Flo EFI. Planning on adding a 150 NOS shot. Currently just running the stock R200 open 3.545 rear. My purpose in replying to this thread is that I am a strong believer in calling the shots as they really are. No holds barred. The value of this forum is be able to share real world experiences so that others can learn and benefit from that. We are a unique group with a common passion for building, racing and otherwise enjoying hybrid Z cars, which many traditional hot rodders don't completely understand or appreciate. There is a wealth of experience and expertise to be shared on this site. We don't want to constrain ourselves by trying to be overly protective, defensive, appeasing, condescending, or politically correct. We have to trust and believe that the contributions of the members to this forum are open, honest, timely and well intentioned. Once we become too timid or thin skinned about honest feedback we become irrelevant as a source of useful information. Case in point, I belonged to a forum of investors a couple of years ago. It got so that if anyone tried to contribute anything that in anyway appeared to disagree or contradict the views of certain senior members of that forum, they were literally attacked by the 'cultists' that supported a certain point of view or acted as guardians for certain other members. Those who had other points of view were all but labeled as 'traitors'. Contributing members spent more time and words apologizing and appeasing than they did exchanging useful information. Needless to say I dropped out of that wasteful exercise. Let's keep this forum open, honest, timely and relevant! Thanks, DanJ Quote Link to comment Share on other sites More sharing options...
Roostmonkey Posted June 23, 2007 Share Posted June 23, 2007 I dont believe that there IS a solution to parts failing when you deal with that kind of power.With those kind of numbers,things break, period. Quote Link to comment Share on other sites More sharing options...
JustinOlson Posted June 24, 2007 Share Posted June 24, 2007 Are the stub axel breaking because of the shock loads associated with the manual transmission? Just curious if a auto car would be breaking these stubs at the same power level. Regards, Justin Quote Link to comment Share on other sites More sharing options...
BLKMGK Posted June 24, 2007 Share Posted June 24, 2007 Heh, you could probably stop the breakage there - and move it someplace else Quote Link to comment Share on other sites More sharing options...
jbc3 Posted June 24, 2007 Author Share Posted June 24, 2007 Let me add a little more here. I am running a Mcleod street twin clutch with a steel flywheel. The steel flywheel is HEAVY. This clutch is awsome, but harsh. It simply does not slip. As far as running an automatic transmission, if it was set-up like a soft street transmission the axles may last a whole lot longer.... maybe forever. But if the transmission has a brake, manual valve body and shifts like a sledge hammer, they, or some other parts in the driveline, are going to give eventually. Drive it hard and breakage is going to happen. The axles are undergoing an autopsy at this point, hopefully giving up some clues to help everyone out. I am waiting for the UPS man to deliver a new set of the same axles from Ross, so I can get back on the road. I built this car to be driven hard, raced at the track on slicks and have fun. I'll be out doing the same thing again soon, can't wait. Jody Quote Link to comment Share on other sites More sharing options...
JimmyZ Posted June 26, 2007 Share Posted June 26, 2007 Just my 2c. I'm not trying to bash anyone here. The truth is that a forged part has a grain pattern which runs with the principal stress in the part. A billet part may be surface hardened by shot peening, heat treat etc but the service life will not approach that of a properly forged and prepared part. The billet's grain pattern is oriented in the direction of extrusion/casting. Nothing wrong with using billet as long as you recognize the shorter service life and regularily check/replace the part before it's too late. Don't see any beachline fractures in the closeup. Therefore this part did NOT fail from fatigue but rather overload. (MHO) That's good in that it shows the part isn't as subject to fatigue failure as one might fear. You just got "lucky" and overloaded the part. Garbage truck drivers who go from reverse to drive without stopping find this sort of thing out. A 70,000 lb truck changing directions through a shaft is a bit much for the shaft to handle. The driveshaft simply twists neatly in two like what you have. 2c Jim Quote Link to comment Share on other sites More sharing options...
katman Posted June 27, 2007 Share Posted June 27, 2007 You'd be hard pressed to see the beach marks from fatigue in those photos and with that post failure rubbing. Regardless, I'm with JohnC on this one- there are no failure proof race parts. The other thread on the AZC control arms is another example. Coincidently an old friend sent me some pics of a fractured flywheel from a Z32 turbo the other day (proly on the net somewhere). Made a real mess of the car. You walk away from stock, and some of us are waayyyy far away from stock like this stub axle case, stuff is going to break, especially if you ain't looking at it. Quote Link to comment Share on other sites More sharing options...
jbc3 Posted July 14, 2007 Author Share Posted July 14, 2007 UPS dropped off my new stub axles today. Got home from work and before dinner I was cruising around the neighborhood. Just in time... there is a car show in my local town tomorrow and the Mid Atlantic Shindig is next week. Thanks Ross! Jody Quote Link to comment Share on other sites More sharing options...
lbhsbZ Posted July 14, 2007 Share Posted July 14, 2007 Any failure analysis yet from Ross? I'd really like to know what caused them to break.....or what it took to overcome their strength. I bought these thinking that they were indestructable (my opinion, not the words or Ross or MM).....and when they arrived, they looked pretty bulletproof. A failure in a road race car may be fatal, so I'd like some info as to their limitations before I chance it. Quote Link to comment Share on other sites More sharing options...
Mikelly Posted July 14, 2007 Share Posted July 14, 2007 This is a great story, and a win/win for all involved... Now, you other guys out there building your "beasts" should seriously consider the amount of force that Jody had to apply to that stub axle to make it fail... Mike Quote Link to comment Share on other sites More sharing options...
katman Posted July 14, 2007 Share Posted July 14, 2007 "so I'd like some info as to their limitations before I chance it" Seems like the limit is here: 1/4 mile 10.629 128.47 MPH 1.540 60' Dyno 1/27/06 NA 404.5 RWHP/405.1 TQ 150 dry shot 517.3 RWHP/588.9 TQ FEA of this part will show it failed exactly where it should have, the minimum section with the highest stress concentration. Even with a material non-linear FE analysis you'd want to run a series of multi sample tests to determine the scatter in the failure load. Then there's the high and low cycle fatigue question. We're talking really big bucks for that test program. There's only so much load you can put through a certain sized peice of metal, unless it's made of unobtanium. Looks like jbc3 found that amount. Bottom line- any time you put on big tires, slap in big engines, or go racing in a straight line or around corners even in a mostly stock car, you've signed yourself up for this sort of thing. Let's be careful out there... Quote Link to comment Share on other sites More sharing options...
jeromio Posted July 14, 2007 Share Posted July 14, 2007 A failure in a road race car may be fatal, so I'd like some info as to their limitations before I chance it.Fatal? How? Do you have drum brakes? If so, change them. Ross sells a nice kit for that too. If the stub fails, the caliper will keep the wheel from flying off. Quote Link to comment Share on other sites More sharing options...
johnc Posted July 14, 2007 Share Posted July 14, 2007 Having experienced a broken right stub axle in a 90 mph left hand turn, I can assure everyone that regardless of what keeps the stub axle/wheel/tire "approximately" in place, having your rear wheel toe change randomly and having that wheel lock up intermittently will make you crap your pants as you try to keep the car out of the dirt. Yes, a broken rear stub axle on a race car can be fatal. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted July 14, 2007 Share Posted July 14, 2007 If you don't want risk you should forget racing and take up shuffleboard or ping pong as a hobby. You'll never take all the risk out of racing. As to reducing the danger or the stub axle breaking, I have two suggestions. 1. Don't use a quaife. 2. Reduce the power. Quote Link to comment Share on other sites More sharing options...
lbhsbZ Posted July 15, 2007 Share Posted July 15, 2007 My main concern was whether or not a design flaw had been discovered during the inspection. I understand that parts will break, especially in the environments that most of us subject them to. If the stubs are as good as they get, fine, I'll just inspect them after each event. If any areas for improvement were found, I'd like to get some revised units. I'm very happy with the stub axles, the machine work looks flawless, and its a beefy piece, but I'm not an engineer and don't have the ability to properly analyse a failure like this. Quote Link to comment Share on other sites More sharing options...
Daeron Posted July 16, 2007 Share Posted July 16, 2007 If you don't want risk you should forget racing and take up shuffleboard or ping pong as a hobby. You'll never take all the risk out of racing. As to reducing the danger or the stub axle breaking, I have two suggestions. 1. Don't use a quaife. 2. Reduce the power. I nominate for "post of the month" even though I do not entirely understand the motivation behind #1. I have long since come to terms with the potential mortality of both my brothers, my uncle, and my dad.. and my uncle is the only one who has gotten into driving beyond local club level (SCCA and HSR roadsters, the SCCA is one of the two BRE cars ) Quote Link to comment Share on other sites More sharing options...
JMortensen Posted July 16, 2007 Share Posted July 16, 2007 Post of the month? Maybe not, but thanks. Seriously though, risk can and should be managed, but there will always be risk, and if there weren't we probably wouldn't want to race anymore. As to the why the Quaife might be more prone to breaking stub axles, it basically all boils down to loosing traction and having all the power go to the lifted wheel. That is a design feature which doesn't couple well with weak stub axles. It is true that a VLSD and a CLSD tend to do the same thing; jack one wheel up and it will spin. The difference so far as I can pin it down is that the Quaife has such an instantaneous torque transfer reaction to the tire lifting. Stub axle failure occurs with all types of diffs, don't get me wrong, it's just that in my experience the Quaife really seems to be an axle snapper, more so than the other types. If you want more detail, it's in here: http://forums.hybridz.org/showthread.php?t=93879 Quote Link to comment Share on other sites More sharing options...
Daeron Posted July 16, 2007 Share Posted July 16, 2007 Post of the month? Maybe not, but thanks. Seriously though, risk can and should be managed, but there will always be risk, and if there weren't we probably wouldn't want to race anymore. As to the why the Quaife might be more prone to breaking stub axles, it basically all boils down to loosing traction and having all the power go to the lifted wheel. Thanks.. as soon as i got this far, I slapped my forehead. Naturally, an effective LSD would be more prone to breaking stuff... (I got off work and I was mad; I had a few beers. The intervening hours have brought my intellect back, d'oh!) Quote Link to comment Share on other sites More sharing options...
stony Posted July 16, 2007 Share Posted July 16, 2007 If you don't want risk you should forget racing and take up shuffleboard or ping pong as a hobby. You'll never take all the risk out of racing. As to reducing the danger or the stub axle breaking, I have two suggestions. 1. Don't use a quaife. 2. Reduce the power. Here's my 2 cents. IF someone took all the recorded (are they) stub shaft breakage incidents and put them into a graph i think you would find that #1 95% of all breakages happen on the drag track I think this one happened at the track just needed one more shot). #2 the breakages occured in cars with 300 + rwhp. I broke many stock stubs trying to break the 11 sec barrier the best 60 foot i managaed was a 1.67 and that was with tires infated to 35 PSI and spinning all the way thru 3rd gear. the fact that this one broke after many "10 second runs and running slicks" says it all. It is much stronger then stock and a GREAT UPGRADE. THE fact is is it is still just a 27 spline stub axle. Once i compared the size of the moser 33 spline axle for a ford 8.8 compared to the 27 spline stub i saw the light. Quote Link to comment Share on other sites More sharing options...
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