OK, I'm back from the salt mines.
The quest for ultimate performance never really ends, does it? The factory solution to any problem always hinges on a cost/benefit analysis that is always heavily biased towards cost and against performance. Aftermarket solutions are based on a cost/benefit analysis as well, but with one or two more factors thrown in: ease of installation and customer service issues.
Let's look at this from an aftermarket suspension manufacturers point of view:
If my instruction sheet for the fitting of a crossmember were 10 pages long, would it get installed correctly, or would it get totally F-ed up by 50% of my customers? What if the FIRST thing on the manufacturers instructions were to torch off the LCA mounts? What if the next instructions was to strip every last bit of undercoating and zinc plating off of both sides of a frame? Would you do it? Now, try and imagine explaining the placement, and installation of 6 frame sleeves.....you only get one chance with a 1" hole saw.
You begin to see the complexities, don't you? A manufacturers phones would be ringing off the hook day and night, and he would have to hold many hands and take back many products. So he compromises. This is not a slant against a manufacturer, but he is trying to make a buck, not get the ultimate in performance.
OK, so now, for someone who has been in this sport for as long as Goat or myself (OMG, I can't believe I just compared Grandpa to my young, virile self), we recognoze what our needs are. We want three things above all else: Performance, durability and driveability. In most cases, you can pick two......but what if you could have all three? Wouldn't you want to try and achieve that state of nirvana? I think so.
My original RE long arm design has been in the rig since before RE introduced the TJ kit to the public. It worked, pretty well. There were compromises however. The crossmember hung 1.5" below the frame, the 6 bushings comprising the forward link mounts flexed like mad under braking and under torque loading, leading to a sloppy feeling on steep climbs. The bushings lasted maybe a year. And, the LCA mounts hung below the axle tube.
So, I had pretty good driveability, good performance, and pretty good durability (I hit a rock the size of a medium sized cooler at 45 mph, destroying a tire and breaking a D-44 spindle, and the suspension showed no dmamage). Again, I was at a compromised position, and felt that I could improve all three aspects of my design parameters.
As Beezil has stated many times, you can't talk XJ suspension design without laying under your rig for about two hours and just puzzling over where the fawk you are going to fit stuff. I went through it all again, string and tape measure in hand, until I figured out the only place I could put a UCA mount on a crossmember so I could have enough vertical seperation to have acceptable anti-dive. Second criteria was the crossmember COULD NOT hang below the frame rails. Period. Figured a way to do that. Now, the whole she-bang had to be able to work around that big mother of a gearbox I run. That was actually the easiest part, especially after I freed my inner Sawzall and cut a very large hole in the floor.
Goat and I both ended up with three links. Two lowers that take impact stress and an upper that mainly serves as torque control. His upper is on the passenger side, and his links are mounted in more or less the factory locations on beefy mounts. The system has proven itself time and again, even in the fast stuff. But he wasn't quite happy. So he tweaked (and not just in the leather-hat-days sense
). He had a bunch of dive under braking, so he moved the torque link a bit, and bingo, much better driveability. Mine has much longer links, which result in less caster change (not really that important in my book), and the torque arm is on the drivers side. So you see, suspension design is and iterative process, sometimes you get convergent design, and sometimes divergent. Sometimes, just when you think the performance of a design couldn't be better, you get a fresh perspective when new kinds of terrain are encountered......or when you want to go stupid fast across the desert with your stroker-jockey buddies chasing you, and the trophy is a fresh pitcher of marguaritas.
OK, pardon the deep thoughts, back to the design. What about control arms. Easy enough, i had plenty of experience to draw on here. I knew Goat had succesfully run a full set of Johnny Joints on his rig with no complaints except for the occasional tightening of a joint. I new I wanted a very solid, non-sloppy feeling so I went the same route, with the exception of the crossmember side of the UCA, which was so tight I needed to use a 1" heim because the overall width of the mount can be smaller. The crossmember UCA mount has three positions for adjustable anti-dive, in case my predictions on the anti-dive feel were off. The axle mounts were moved up flush with the tubes, so another compromise was defeated. Tubing is 2" x .25 4130 Chromoly, which I have had very good luck with in the past. Upper arm is 1.75" x .120", because it doesn't see nearly as much impact loading and it doesn't drag in the rocks.
{Insert pics here.....I'm lame and need to get the F-ing film developed}
The testing has yet to commence mostly due to the stroker build-up, but it should be on the trail soon for testing. I will not hesitate to report problems in any of the three main objectives, and I can already see that I may as well just order the coilovers now....
Now, if someone wants to explain to me how you could reasonably design such a tight-fitting suspension around 18 production years of Jeep, incorporating 4 different T-cases, 6 different transmissions and various exhaust configurations, I'm all ears, because I think I could make a boatload of cash doing it.
CRASH
OMG, this may be my longest post ever. I'm in the same league as SteinJeep!
