Inc's SFA KJ Build...

Inc · **Posted:** Thu Aug 27, 2009 1:43 am

Yeah, it is pushed up pretty good, but to be honest I haven't seen any pics of where it sits since they got the axle under it. :lol:

They took it back out to do this work. I think he said the wheelbase should be around 107". We also decided to add some extra structural support to the rear axle truss. We are going to add some bracing from the bottom of the truss that connects to 2 or 3 of the top bolts for the rear diff cover. There is a lot of force on that truss and they have been known to bend or break so I figured better safe than sorry.

Inc · **Posted:** Thu Aug 27, 2009 1:45 am

Random side note as well. I had to chop off the 2 light tabs that are on top of my bumper to get the winch to fit. I forgot to mention that before. They stuck out too far and didn't fit being in the center of the bumper, right where the winch goes. So I'll re-weld them back on more outboard on the top bumper tube.

2006 KJ · **Posted:** Thu Aug 27, 2009 9:21 am

looking good inc.. great to see progress. I have a question on your rear end set up. when we ordered the long arm kit for my fathers rubicon (from rubicon express) it was offerend in a 4 link rear or a set up like TJKJ's with a trackbar. They (rubicon express) said that the 4 link was more for a rig mostly to be used on trails and the trackbar set up had much better road manors. Do you know what the main difference/characteristics are between the 2? I assume the 4link will flex like crazy but then again our rubi flex's like crazy with the track bar set up.

Inc · **Posted:** Thu Aug 27, 2009 1:22 pm

2006 KJ wrote:

looking good inc.. great to see progress. I have a question on your rear end set up. when we ordered the long arm kit for my fathers rubicon (from rubicon express) it was offerend in a 4 link rear or a set up like TJKJ's with a trackbar. They (rubicon express) said that the 4 link was more for a rig mostly to be used on trails and the trackbar set up had much better road manors. Do you know what the main difference/characteristics are between the 2? I assume the 4link will flex like crazy but then again our rubi flex's like crazy with the track bar set up.

To be honest I am not sure how they will handle differently. I know the 5 link rear is said to handle better on road, but I am not worried about it at all. I didn't want to hassle with a rear track bar, not the slightest. Since I am running the HD 864 rear springs, I am not worried about it being too loose out back though. Should be good t go with the setup as is.

Pics of the front under the jeep. I need to correct myself, the wheelbase is 110" , not 107" like I said last night. The 250 and 350 coils are too soft, that little experiment is over and I am going with the 450 and 550 springs. The unibody up front in the fender wells, needs to be trimmed. The wheel spacers are not on in these shots by the way. The support between the rear mount brackets and the cross member still needs to be made, the rear gears, the tack bar bracket, the steering box and the custom skid all need to be done still. He is devoting all of his time to it though and put his airplane work on hold.

Neatus · **Posted:** Thu Aug 27, 2009 1:54 pm

How can you tell the coils are too soft...are they just compressed too much?

Inc · **Posted:** Thu Aug 27, 2009 1:58 pm

Neatus wrote:

How can you tell the coils are too soft...are they just compressed too much?

They only have like 1 3/4" left of adjustment, and the coils are already almost touching.

Inc · **Posted:** Thu Aug 27, 2009 3:12 pm

Hopefully nothing else comes up and he can bang the rest of the stuff out this week and have it ready Saturday, if not it will be another week until I can pick it up next Friday. Even then I have to take it to an exhaust shop, by trailer, and then another shop for the SYE kit and drivelines. I kind of want to install the SYE kit and drivelines myself though, so maybe I can have the driveline guys get me the parts and I can install the stuff myself after they finish the exhaust.

We'll see. :roll:

Inc · **Posted:** Thu Aug 27, 2009 5:35 pm

It will be a week or 2 before it sees any dirt or rocks because of the exhaust and drivelines. Hard to get it anywhere without the exhaust hooked up at all, and no rear driveshaft.

daspes · **Posted:** Thu Aug 27, 2009 6:44 pm

Inc wrote:

I was hoping for 108" wheelbase but with the 35s and those front arm clearance issues 110" will be good.

Holy smokes! My JK Unlimited is 116"! Stoopid Guv'ment computers. I have to wait till tonight to wee the pics....

daspes · **Posted:** Thu Aug 27, 2009 8:03 pm

Looks nice Mike. Question though, at flex it looks like your gong to be hitting the front bumper/unibody/frame/crossmember/thing. Is it just the pics, or are you going to have to tweak arm placement even more?

Inc · **Posted:** Thu Aug 27, 2009 10:10 pm

daspes wrote:

Looks nice Mike. Question though, at flex it looks like your gong to be hitting the front bumper/unibody/frame/crossmember/thing. Is it just the pics, or are you going to have to tweak arm placement even more?

Yeah, they would hit when flexing. We be choppin. :wink:

greatoppressor · **Posted:** Fri Aug 28, 2009 10:31 am

Man, that looks incredible!

Noob questions (I'm learning)...

I notice you have only two "main" control arms on the front with smaller "sub" control arms to control the front diff/shaft angle. Is there a name for that configuration? Why would you do it this way instead of having separate upper and lower control arms (expense, simplicity, space constraints, etc)? Since this arrangement doesn't keep the front diff angle constant, would that cause an issue with the u-joints in the front drive shaft, or does it have CV joints?

Again, that rig looks outstanding!

-SR-

Inc · **Posted:** Fri Aug 28, 2009 10:50 am

greatoppressor wrote:

Man, that looks incredible!

Noob questions (I'm learning)...

I notice you have only two "main" control arms on the front with smaller "sub" control arms to control the front diff/shaft angle. Is there a name for that configuration? Why would you do it this way instead of having separate upper and lower control arms (expense, simplicity, space constraints, etc)? Since this arrangement doesn't keep the front diff angle constant, would that cause an issue with the u-joints in the front drive shaft, or does it have CV joints?

Again, that rig looks outstanding!

-SR-

The long arms up front are called radius arms. It is a 5 link/radius arm design. the arms have 4 links to the axle and the track bar forms the 5th. My desire was to stay away from making as many mounts to the unibody frame as I could get away with. With the radius arms, there are only 2 mounts to the unibody up front. In the rear I have 4, but I am not using a rear track bar or sway bar out back. With the 5 links on the front axle the angles will not be a problem. The 4 mounts on the axle from the radius arm design will hold the axle from rotating and the track bar controls side to side movement. The stock drivelines are way too short, so I have to get new ones but since the wheelbase is stretched the drivelines angles won't be as bad as if I didn't stretch it. That and I am getting a SYE for the rear of the t-case which will lengthen the rear driveline even more and make a better angle as well.

2006 KJ · **Posted:** Fri Aug 28, 2009 11:18 am

INC.. make sure when you get the SYE (and assuming you'll have a CV drive shaft) that you get one that is long enough.. because when it flexes you dont want it to be using the drive shaft to limit the drop (can damage it internally) and KEEP IT GREASED! if not you'll get a 'snapping' noise that you wont be able to track down because it only happens over sharp bumps. too us forever to find it. ended up having to put it on a lift, then jack the rear end up and down on both sides until we found it was the driveshaft. just a heads up

Inc · **Posted:** Fri Aug 28, 2009 11:27 am

2006 KJ wrote:

INC.. make sure when you get the SYE (and assuming you'll have a CV drive shaft) that you get one that is long enough.. because when it flexes you dont want it to be using the drive shaft to limit the drop (can damage it internally) and KEEP IT GREASED! if not you'll get a 'snapping' noise that you wont be able to track down because it only happens over sharp bumps. too us forever to find it. ended up having to put it on a lift, then jack the rear end up and down on both sides until we found it was the driveshaft. just a heads up

Yeah, I am having a custom driveline shop get me the correct length rear end.

Inc · **Posted:** Fri Aug 28, 2009 8:41 pm

took a few shots today

nothing fancy, just parts shots (sorry crappy pics).

The rear half of the frame stiffeners, the front half is already welded in and then the two halves will be welded together.

The lower coilover mounts.

Unibody side of the front lower control arm mounts.

really hard to tell in this pic but yo can see on the right at least, where there are gussets that go up the side of the unibody and are welded in. super beefy.

Getting there...

I also picked up the new springs for the coilovers today, swapped them right out. Have them back on tomorrow.

tjkj2002 · **Posted:** Fri Aug 28, 2009 9:03 pm

Inc wrote:

greatoppressor wrote:

Man, that looks incredible!

Noob questions (I'm learning)...

I notice you have only two "main" control arms on the front with smaller "sub" control arms to control the front diff/shaft angle. Is there a name for that configuration? Why would you do it this way instead of having separate upper and lower control arms (expense, simplicity, space constraints, etc)? Since this arrangement doesn't keep the front diff angle constant, would that cause an issue with the u-joints in the front drive shaft, or does it have CV joints?

Again, that rig looks outstanding!

-SR-

The long arms up front are called radius arms. It is a 5 link/radius arm design. the arms have 4 links to the axle and the track bar forms the 5th. My desire was to stay away from making as many mounts to the unibody frame as I could get away with. With the radius arms, there are only 2 mounts to the unibody up front. In the rear I have 4, but I am not using a rear track bar or sway bar out back. With the 5 links on the front axle the angles will not be a problem. The 4 mounts on the axle from the radius arm design will hold the axle from rotating and the track bar controls side to side movement. The stock drivelines are way too short, so I have to get new ones but since the wheelbase is stretched the drivelines angles won't be as bad as if I didn't stretch it. That and I am getting a SYE for the rear of the t-case which will lengthen the rear driveline even more and make a better angle as well.

You now that RE makes rear radius arms now.

Inc · **Posted:** Fri Aug 28, 2009 9:22 pm

tjkj2002 wrote:

You now that RE makes rear radius arms now.

Yeah, for JKs now IIRC. Since I didn't have any info on them or know anyone with any experience with them, I passed.

Inc · **Posted:** Tue Sep 01, 2009 12:10 am

Update, but no new pics.

Loads and loads and more loads of welding today. All those rosette welds were finished today finally, and the rest of the unibody stiffeners were welded in. The final frame stiffener piece, which I am sorry to not be able to show yet, is the Clayton ZJ frame stiffeners that were cut down to size and fit in between the rear lower long arm mounts and the t-case cross member. It fills in the gap scene in this pics between that rear mount and the crossmember and sits flush with the level of the bottom of the crossmember to forma nice flat surface. (the rear mounts will have skids welded over them as well.

and since it is welded in, it connects this front mount

to the rear mount

So those two unibody stiffeners in the pics are welded to the unibody, then welded on the seam where they meet to join them as one piece, and then the ZJ frame stiffeners are welded to both pieces over the welded seam, filling in a gap where I could have more easily been hung up and joining the pieces again for added strength. Super beefy.

When I swapped the coilover springs at Summit on Friday, they didn't have any 550 rated springs so I picked up 500 rated ones and Chris said they are perfect. So I think that the coil rates give or take 50 pounds should work out fine either way, for those looking at different spring rates.

Inc · **Posted:** Tue Sep 01, 2009 10:21 pm

After looking and discussing the rear axle truss, we decided to beef it up. These parts were added today. Should make it a lot stronger.

and painted

Inc's SFA KJ Build...

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