4Link 1st Try

[TheCompound]

Any help or suggestions would be great! I know its just the top of the 4link cal. If you need the rest I can down load it later

[Ken L]

I would shoot for an anti-squat of closer to 100. That's where I have mine and the rear stays nice and level under accelleration and torque load, and it doesn't compress when climbing hills and I have to give it some throttle.

[zjeepin]

post the side view..

it looks pretty good to me so far.. I'm currently running about 70% AS front and rear and i'm extremely happy with it.. I'll be interested how you go about getting that much frame end vertical separation.. I have my upper links front and rear coming up through the floorboard..

[SirFuego]

The AS issue seems to be a topic of debate. But I will say that since anti-squat can be affected by the mounting locations of the upper control arms, that you might want to make those mounts adjustable (if you can) to a certain range of theoretical anti-squat values so that you can always change it if you aren't happy with its performance.

Is this a front or rear application?

[zjeepin]

The AS issue seems to be a topic of debate. But I will say that since anti-squat can be affected by the mounting locations of the upper control arms, that you might want to make those mounts adjustable (if you can) to a certain range of theoretical anti-squat values so that you can always change it if you aren't happy with its performance.

Is this a front or rear application?

good suggestion jared.. i did forget to mention I have adjustment from ~60-70-90% AS (rear suspension) and ~60 & 70% upfront.. I may play with adjusting it sometime but i've left it alone since the build because im really happy with how its working..

[TheCompound]

Its for the rear.

So from what Im hearing I need to increase the AS some. The best way to do this would be to move the upper frame side mounts up?

Im sure Ill be cutting up the floor, a little scared to start cutting without a good plan set!

Thanks for everyone help, Im still trying to figure out how the different link end locations effect the final numbers.

[TheCompound]

1 question, without the heep sitting on its own tires. What is the best way to figure/ adjust the Frame End Z (height from the ground)?

[Ken L]

Do you have measurements to the center of the axle and the unibody height with the Jeep on the tires? Regardless of how it's sitting now, in order for the calculator to work right you need those measurements. Once you have them, you can change the measurements based on those dimensions (change the LCA frame side mount up or down 1" for example)

[TheCompound]

ewwww... It was on 31' with 4.5 of lift... I think I have them somewhere... hope Im not screwed! Maybe someone has some to get me close!

[AgitatedPancake]

Your setup doesn't look bad!. I like the numbers the calculator put out. Claytons supposudly has somewhere around 100% anti-squat, and there have been a couple occasions where it has frustrated me how hard the rear end pushes away from the jeep. I'd rather h ave it less responsive to the torque (less anti squat)

Increase anti squat by lowering your frame side upper link mounts, decrease anti squat by making your uppers and lowers closer and closer to parallel from the side view (increasing UCA height at frame).

I'm a little worried about those shorter upper links, it seems like they would cause your pinion to rotate downward as you droop out. Not exactly a characteristic you want (if it's too severe!)

[TheCompound]

Your setup doesn't look bad!. I like the numbers the calculator put out. Claytons supposudly has somewhere around 100% anti-squat, and there have been a couple occasions where it has frustrated me how hard the rear end pushes away from the jeep. I'd rather h ave it less responsive to the torque (less anti squat)

Increase anti squat by lowering your frame side upper link mounts, decrease anti squat by making your uppers and lowers closer and closer to parallel from the side view (increasing UCA height at frame).

I'm a little worried about those shorter upper links, it seems like they would cause your pinion to rotate downward as you droop out. Not exactly a characteristic you want (if it's too severe!)

You know I was just looking at that... They are pretty short.

How close can the uppers and lowers be in lenght?

[zjeepin]

The uppers and lowers can be the same length but most folks shoot for uppers around 3/4 of the lowers..

[SirFuego]

Not sure which version you are using, but IIRC the newest version has a "pinion change" output that shows how much the pinion angle changes throughout travel. Haven't toyed with it though, so I don't know how helpful it is in figuring out optimal UCA length.

[TheCompound]

Not sure which version you are using, but IIRC the newest version has a "pinion change" output that shows how much the pinion angle changes throughout travel. Haven't toyed with it though, so I don't know how helpful it is in figuring out optimal UCA length.

Thanks, but this one is kicking my a$$, LOL all i need is more data

[TheCompound]

Upper is 75% of lower

[IndyZJ]

The uppers and lowers can be the same length but most folks shoot for uppers around 3/4 of the lowers..

What kind of driveshaft you run usually determines what you want the pinion to do (and how long to make the upper links in relation to the lowers). If you were running a double cardan joint at the Tcase, you'd want slightly longer uppers than lowers to keep the pinion pointed at the Tcase as the axle droops. Of course, this is idealistic and doesn't always work when building around something like a ZJ. Run some numbers and make sure you keep the driveshaft from binding - you could even run a center limit strap if you wanted. That said, don't copy the old Teraflex kits.

The "70% rule" for length is really kind of a myth that probably came from a magazine a decade ago from one particular application that people seemed to get fixated on. On a full bodied rig, you're pretty constrained by the existing structure. Since you're willing to cut into the floor, you can get MUCH better AS than what the kits come with. Your current plan really doesn't look bad IMO.

[TheCompound]

IndyZJ, everyone is saying it doesnt look bad, but what could look better?

[ATL ZJ]

Run some numbers and make sure you keep the driveshaft from binding - you could even run a center limit strap if you wanted.

I dont know what axles you have, hopefully one tons based on your tire size, but if you run 1410s you can get more droop without bind. I'd still recommend center limit straps just for purposes of longevity though.

I get by with single ujoints (non double cardan shafts) f/r with a lot of droop. It can be done, just plan well.

The "70% rule" for length is really kind of a myth that probably came from a magazine a decade ago from one particular application that people seemed to get fixated on. On a full bodied rig, you're pretty constrained by the existing structure. Since you're willing to cut into the floor, you can get MUCH better AS than what the kits come with. Your current plan really doesn't look bad IMO.

Agreed. Anything from 60% length uppers to uppers and lowers being the same length should be able to work fine. Just confirm that the pinion angle won't change too much in the calc. A much more important "rule" is maintaining close to 25% of your tire size in vertical separation at the axle end, which you are close enough to with 8" separation.

[ATL ZJ]

IndyZJ, everyone is saying it doesnt look bad, but what could look better?

Maybe get the instant center farther out. Change your tire rolling radius to 19 also, assuming you do plan to air down. Could be throwing your numbers off some.

[IndyZJ]

"Better" depends on personal opinion. You're also limited by what physically fits. My only concern would be the pinion dropping under droop, but it may still be within the limits of your driveshaft. If you can't move the uppers, you could always shorten the lowers a little bit to keep the pinion pointing the right way. You don't need 3' links to get good performance - shorter links can improve belly clearance and even give better geometry in a lot of circumstances.

Whatever you decide on paper, make sure to make the upper mounts adjustable to change the AS in case you aren't happy with it in real life.

This is just my .02, of course.

[IndyZJ]

Maybe get the instant center farther out. Change your tire rolling radius to 19 also, assuming you do plan to air down. Could be throwing your numbers off some.

And what he said.

[TheCompound]

Maybe get the instant center farther out. Change your tire rolling radius to 19 also, assuming you do plan to air down. Could be throwing your numbers off some.

"Better" depends on personal opinion. You're also limited by what physically fits. My only concern would be the pinion dropping under droop, but it may still be within the limits of your driveshaft. If you can't move the uppers, you could always shorten the lowers a little bit to keep the pinion pointing the right way. You don't need 3' links to get good performance - shorter links can improve belly clearance and even give better geometry in a lot of circumstances.

Whatever you decide on paper, make sure to make the upper mounts adjustable to change the AS in case you aren't happy with it in real life.

This is just my .02, of course.

Thank you both, well I got the adj. upper mounts from RuffStuff so I hope to be ok there!

Ill work on this a little more, then start tacking it in this weekend!