ok heres a link of all these different kind,
http://www.spohn.net/shop/1993-1997-...-Control-Arms/

the questions are.
Why do they make tubular ones?
Why are there boxed ones?
what makes boxed ones more expensive?
and why are there adjustable ones?


sorry this might seem dumb but i looked at the descriptions of all of the LCA's but just couldnt figure out the advantages.

 

Between box and tube of equal dimension/wall thickness, tube has the same strength at all orientations; box is stronger across the flats, weaker across the diagonals. Box is heavier as there is more material (2" box has 8" circimference versus 6 1/4" for 2" tube); more material, more cost. Adjustable LCAs and torque arm allow you to rotate the axle housing to alter the pinion yoke angle. The rod end or "del sphere" give you better articulation over poly ends but at the cost of a harder ride.

 

The primary pupose of the adjustment feature on the LCA it to adjust the thrust angle of the rear axle (keep it perpendicular to the longitudinal axis of the vehicle), and to move the axle assembly forward and backward to center the wheels in the wheel well. There isn't really much you can do with that adjustment to alter the pinion angle. Moving the axle forward or backward 1/2" will not change the angle very much at all. The rotation of the pinion about the centerline of the axle is controlled totally by the torque arm.

The weight savings for tubular is fairly dramatic. In the Spohn LCA's the boxed are 2" x 1.5" x 0.120" wall thickness. The tubulars are 1.25" diameter x 0.095" wall thickness. That results in the tube weighing only 45-percent of the weight of the box (but don't forget to add the weight of the "ends"). The primary load on the LCA is pure axial compression, when the vehicle is accelerating, axial tension when braking. With soft rubber bushings or the spherical rod ends, torsional and bending loading is effectively eliminated.

I've seen the Spohn tubular LCA's push a 3,500# 4th Gen making 1,350HP at the flywheel, into the low 8's at close to 170 MPH. I think the design is adequate for most of us.

 

hmm so what do you guys recommend im assumung tubular?

 

Yes.

http://www.injuneer.com/images/photo.../DCP04293a.jpg

 

i just looked at your page nice car bro. and i think instead of getting new stange s60 rear end ima just get the LCARBS and LCA's with my tax returns.

 

Though the ride will be slightly harsher and bit noisier, I would suggest a rod end as they have a greater range of motion than poly. I have the "del sphere" from spohn which is basically a rebuildable/greasable rod end.

 

can you send me a link?

 

You already posted a link to the Spohn site, and the Del-Sphere rod ends are right at the bottom of the page you linked.

 

oh ok sorry about that

 

Sorry to hi-jack. But I have a question concerning the setup with adj lca's. As you said injuneer, the purpose is more or less to keep the 3rd member square, and that the moving forward or backward .5 inches doesn't really affect the pinion angle. That having been said, my question is, could there be any type of gain by setting the rearend further forward, or backward from the stock location? Mine is square now, but this just came to mind, I was thinking it might make the car more stable( if a person needed to) but probably not enough to do anything, by moving the rear tires back further. Sorry just a what if type question. Thanks for humoring me.

 

I don't consider that hijacking the thread it will help me learn more.

 

Thrust angle is not the same as pinion angle. Pinion angle is controlled by the torque arm. Thrust angle is the angle the axle is relative to the center-line of the car.

Rear control arms are replaced with aftermarket pieces for a few main reasons:

1) Increase in strength (Tubular and aftermarket boxed are much stronger than the stamped sheetmetal)

2) Add stability (The poly ends or rod ends are going to have less give, and tighten up the suspension)

3) Add adjustability (When swapping other axles in, or in general, not all cars/parts are perfectly straight, as such the thrust angle can be off and the car can "crab-walk" down the road; or the axles are not centered in the openings)

4) Reduce weight/strength (Chromoly parts can be lighter than factory, but many many times stronger, but these do cost more than normal DOM aftermarket pieces)