I put a Go Pro camera under the jeep to watch the amount of axle wrap in a spring under application. Was surprised by the amount of axle wrap. Can only imagine the amount with a SOA.
93YJ 4.8L Vortec,AX15,Atlas 4.3:1, 4.56 Gears, Dana 30 w/ Posi-lok,Dana 44 Rear w/ Ox Locker + 99 Explorer Disk Brakes,Tom Woods D. Shafts,1" Body, 2.5" ED RE Lift, 33" BFG KM2 T/A's with MT Classic II Wheels, Herculined Inside, Electric Fan, 20 Gal Tank Conversion,Tuffy Center Console,Warn Front Bumper, Rockhard 4X4 Rear Bumper w/ Tire Carrier,Bushwacker Extended Flat Fender Flares,AMSoil/Redline In Everything and the List Goes On....
88YJ 4.2L: Interior and mechanical overhaul including engine replacement, nutter bypass, Weber 34 Carb, and work on a whole bunch of other things to get it back to fine running condition without the emissions control...evap cannister kept functional as well as PCV system, and manifold heater.
I went without one for quite some time. It can be done but compromises must be made. The trick to it is building to handle wrap and not caring about the outcome short of breaking stuff. Fist and foremost an SYE is crucial. I've seen many SOAs without which is surprising. You have to make absolutely sure your pinion input is properly pointed. We all know this but there are extra considerations if you aren't planning an anti-wrap bar at the time of the build. When doing this you must do so at trail weight not DD weight. This is often overlooked. Chances are you don't DD your jeep with multiple passengers, a big cooler, camping gear and your buddy nicknamed "Chowder." The next factor is spring settling. You must account for the spring to sag and even get twisted into the "S" shape that happens without an anti-wrap bar. Now it is my feeling that there is nothing inherently wrong with saggy spring packs and even the dreaded "S" bend. I think they actually work better that way. The problem is that "S" bend will cause the pinion to point higher then it would without the bend. So as you wheel more and the bend gets enhanced your pinion will walk upwards. It has been my expereince that the bend will only happen to a point and not continually get worse. If you add all the issues together; heavier at trail weight, saggy springs, "S" bend, and you couple that with a bit of spring wrap then you are going to break. So when choosing a pinion input angle you might want to add a few degrees down to anticipate these factors rather then the satandard 2*.
If you want to further reduce your chances of pinion ujoint issues then use a companion flange style connection. I have found them to be hardier then the standard yoke. Many will swear by the ubolt conversion on standard yokes as well. I wouldn't call it a band-aid fix but if you are having problems with throwing ujoints then it is possible this wont help. I've stretched ubolts just as easily as straps. The other problem with the ubolt style is it is very easy to over tighten them allowing the caps to deform. You also want to perform droop tests to see if your suspension will go beyond what your ujoint will allow. At one point my standard TW shaft just wouldn't accommodate the amount of travel that a loose SOA would allow. There are tricks to helping this like relieving the yoke and DC center of excess metal to allow for more angularity. You can also keep a bit of Tcase drop. Yes you can have both an SYE and a tcase drop. I used the combination for a time before i rid myself of the TW standard shaft. Another way to help with wrap is to maximize the length of your rear driveshaft. Personally i think if you plan to go SOA a supershort SYE just makes sense. Couple that with even a moderate rear stretch and this can help. This is why trucks don't seem to have any issue with axle wrap destroying ujoints, their rear shafts are 10' long. Another thing you can do is keep your static rear drive shaft angle as low as possible. This might seem SOP but seeing super high SOA jeeps is pretty common. Think of your SOA as a suspension style rather then a "lift." You might think that sitting up high looks cool but in short time you will be looking for ways to get it back down. Many of us have been though this. Excess lift will create excess headaches later. I use a high pinion rear axle assembly and this also helps with the angles. Another way to alleviate problems is to not ask your jeep to do what you think it shouldn't. Take it easy, know its potential weaknesses and wheel accordingly. If you like sand dragging then a SOA without anti-wrap bar isn't for you. Sand will make even a SUA wrap. If your plan is to go to JV with your first SOA build and show the oldtimers up then a SOA without anti-wrap bar isnt for you. It is possible to be successful with a SOA and no anti-wrap bar but you have to pay a bit more attention to details and there are some compromises to be made that maybe on first build you are ok with but Later you might find that they are limiting your fun.
-insert meaningless out-of-place political diatribe-
question though: I have read that the traction bar needs to mount "as far ahead of the t-case tail as possible" but this confuses me as to why- isn't all we really need in a traction bar that it have the same droop and arch potential of the front spring mount eye?
Otherwise a it seems to me a whole different problem emerges- oscillating bending of the spring created by the two different radiuses of springs vs. the traction bar.
SOA is probably where I will end up. The fabrication of everything is fine but the not-easily-home-fab'd SYE I will have to save up for.
you want the longer bar because with a shorter one you give the axle more leverage, so instead of the axle wrapping you will just be lifting that corner of the jeep. the longer the bar, the more controlled the axle is. and thats why you build a shackle on the frame end of the bar and use flexable joints. when i had one my bar went about 6 inches past my spring mount and it didn't limit any flex
1994 yj stretched, locked and loaded - 6.0l vortec lq4, 4l60e, np231, Dana 44s 37" interco trxus m/t, 3.5" bds front leafs, double triangulated 4 link rear on xj front coils.
1997 ZJ limited - BONE stock
2003 tj - 4in skyjacker, 33" mickey thompsons
my on board alternator/welder write up
my tj 1/2 doors on a yj write up
RC vs BDS