4" lift kit

[jakbob]

ok, i know that to do a four inch lift, you need a one inch tcase drop , shocks, and springs, but i was looking at rustys kit and it has all this:

-front adjustible trac bar
-lower control arms
-front sway bar disconnects

and i thought an xj only had two control arms in the front, if thats the case, would i need lower or upper control arms?

 

[TwistedCU]

For 4" of lift an adjustable trackbar is needed, as is the TC drop.

The swaybar can be corrected one of three ways:
Swaybar drop brackets
Longer swaybar links
Longer swaybar links with quick disconnects (this is the way to go if you plan on hitting trails and spending the $$$ for JKS or similar is worth it)

As for control arms, at 4" of lift you can still get factory spec correct caster, but the ride will be harsh. Lower arms will help, all 4 arms will help more. 4-4.5" of lift is really the threshold at which a long arm kit becomes the correct way to address linking the front axle. It is much more expensive which is why 4" is a very popular lift height for XJ's and TJ's.

As you lift the Jeep, the axle is moved farther under the Jeep, and this puts the control arms at a severe angle compared to where they are in stock form. This makes them have to move up and forward to absorb an impact from a bump or obstacle, hence the rough ride. Adjustable or longer "short" arms will move the axle forward a bit to correct this somewhat, but "long arms" move the mounting location further back and lower, evening out the angle and restoring a stock like ride (not to mention awesome articulation).

I ran my XJ for several months at 4" and stock arms. Adding lower arms did more for wheel travel than it did for ride quality but it did help some.

 

[Bounty__Hunter]

The XJ has 4 control arms in the front, same as TJ's and ZJ's and MJ's. At 3" and 4" of lift you really only need longer lower control arms to get your caster within spec and help prevent death wobble.

I've got 5.5" coils on my MJ and had to build custom upper and lower control arms to get the proper caster, wheelbase, and pinion angle.

 

[TwistedCU]

At 3" and 4" of lift you really only need longer lower control arms to get your caster within spec

You can get caster in spec with 4" of lift ans stock arms. I did.

 

[xjpioneer]

ok first of the rustys lift come with shocks and a t case drop and the spring pack comes with everything you need to do the lift with out any extras and the front axle has 2 upper and 2 lower control arms and the uppers are not needed unless yuo really want to spend the extra money

 

[Bounty__Hunter]

At 3" and 4" of lift you really only need longer lower control arms to get your caster within spec and help prevent death wobble.

I know.

 

[jakbob]

ok first of the rustys lift come with shocks and a t case drop and the spring pack comes with everything you need to do the lift with out any extras and the front axle has 2 upper and 2 lower control arms and the uppers are not needed unless yuo really want to spend the extra money

i know, but im thinking bout buying rustys rear leaf springs and rubicon express front springs from twistedcopper and i was wondering what else i needed. and if all of that was completley neccesary. ill probibly just get the tcase drop and brake line brackets and shocks and then get the control arms later...