Boxing Control arms.

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mooktank

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Sep 27, 2004

#1

• Sep 27, 2004

• #1

Has anyone here ever boxed stock control arms before? Im thinking about doing it since i have the steel and the welder lying around. Think it will be worth the work or will it do nothing. It looks to me like the uppers need it the most. But i will do both.

 

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mooktank

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Sep 27, 2004

#2

• Sep 27, 2004

• #2

and im getting poly housing bushings for the uppers too. Im guessing this will help out a lot.

 

1986LX2002

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Sep 27, 2004

#3

• Sep 27, 2004

• #3

yeah it will def help, if you really want to go extreme use delrin bushings instead of poly but only bad thing is you would probably wind up breaking parts since you will have no movement from the bushing at all.

 

Mavrick

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Sep 27, 2004

#4

• Sep 27, 2004

• #4

You do not want to box the upper control arms.. for handling sake you want some flex. The bottoms would benefit with the added strength of a boxed shape. You have to be careful with the sway bar though..

And the bushings, you don't want HARD bushings on both sides of any control arm, this creates bind and equates into bad handling characteristics (although GREAT for drag use only).

Can you tell i've been researching this stuff lately?

 

rd

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Ocean Springs MS

Sep 27, 2004

#5

• Sep 27, 2004

• #5

Yes, I have boxed a set of lowers and a set of uppers. The lowers have been on the car for a year or so, work fine. I still put my traction bars back on, so I don't have a direct comparison of improvements, but with both it lauches better than with neither, and with bars, it is better than just the boxed LCAS, from what I remember.

I boxed the uppers, but I have not gotten around to installing them. Same for some poly bushings in the lowers.

Total cost was about $20 for some 1/8 in flat steel, and I bought a new roll of welding wire. Made some cardboard templates, cut them out with a torch, ground to fit, and welded them in. I welded in short beads, alternating sides, ends, etc. I cut and welded some new swaybar brackets also. You could leave the originals in place and just cut a slot for them, but you could never remove them once you weld the plate on. My new brackets seem to also work fine. Painted when done. Be careful not to overheat the bushings when welding.

They seemed to fit fine.

It now does 1.88 to 1.95 sixty foots, with all stock 1980 rubber bushings still in place.

 

trbkrb

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Jun 4, 2001

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Houston, TX

Sep 27, 2004

#6

• Sep 27, 2004

• #6

Here is an article done by a friend on boxing the control arms:

http://oldwestracing.com/articles/armsbox/BCAwo.htm

 

M

mooktank

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Sep 27, 2004

#7

• Sep 27, 2004

• #7

so you think ill be fine with boxing the lowers and only replacing the differential bushing on the uppers without boxing them?

 

M

mooktank

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Sep 27, 2004

#8

• Sep 27, 2004

• #8

so you think ill be fine with boxing the lowers and only replacing the differential bushing on the uppers without boxing them? I also dont think im gonna totally box the lower so i can get the sway bar out. I am gonna do it with the arms on the car though.

 

8

88mustangGT

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Apr 6, 2003

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Sep 27, 2004

#9

• Sep 27, 2004

• #9

what about boxing the front control arms?

 

rd

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Ocean Springs MS

Sep 27, 2004

#10

• Sep 27, 2004

• #10

Somehow, it seems that boxing the lowers would be the first thing to do. They would see compression upon launch, the uppers would see tension, I think. Otherwise you would not get wheelies.

Read the Doorslammer Chassis book, but have not applied much of it yet.

Have not gone through this, but has anyone else done the physics?

 

Mavrick

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Sep 27, 2004

#11

• Sep 27, 2004

• #11

88mustangGT said:

what about boxing the front control arms?

Click to expand...

I'm pretty sure that'd be pointless. The whole point of boxing rear control arms is to add strength.. a box is stronger than a stamped steel U shaped control arm.

The rear control arms transfer torque from the axle to the chassis, creating movement of the whole car. The front control arms have nothing to do with transfering torque.

 

Gearbanger 101

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#12

• Sep 28, 2004

• #12

Don't bother boxing them if you don't plan on replacing the bushings. Solid are great, but you'll suffer from ride deterioration and they’re kind of hard on the torque boxes when you eventually do get traction. On a streetcar that's not going to see much track time, I'd go half polly and half rubber if I were you. Mavrick, I don't understand how you don't think that stiffer control arms wouldn't improve handling? Taking the flex out of the arms will allow the suspension to properly do it’s job and reduce the amount of energy transferred through the arms and throughout the rest of the body.

 

Mavrick

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Sep 28, 2004

#13

• Sep 28, 2004

• #13

For lowers yes, but from the research i've done on the Corral in the last little while.. you want to leave the uppers alone. Wouldn't you rather have the upper control arms flex a little instead of having the bushings bind when cornering?

 

Gearbanger 101

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#14

• Sep 28, 2004

• #14

Mavrick said:

For lowers yes, but from the research i've done on the Corral in the last little while.. you want to leave the uppers alone. Wouldn't you rather have the upper control arms flex a little instead of having the bushings bind when cornering?

Click to expand...

That's why I suggested a combination of rubber and polyurethane. The rubber bushings in the axle end of the rear end prevent the binding you described under hard cornering. I do agree with you that the majority of the stress is placed on the lowers. And their longer length makes them more prone to flex, but most users I know (and some manufactures also) insist that combining the bushings solves the binding problem. I myself ran a combination of rubber and Energy Suspension bushing in my LX and they worked out just fine.

 

Mavrick

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#15

• Sep 28, 2004

• #15

Cool. I may buy softer rubber bushings for the axle end of my upper control arms, as right now i have the hard urethane bushings on the axle end.. and the HPM uppers have hard bushings on the frame end.

 

Gearbanger 101

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#16

• Sep 28, 2004

• #16

Mavrick said:

Cool. I may buy softer rubber bushings for the axle end of my upper control arms, as right now i have the hard urethane bushings on the axle end.. and the HPM uppers have hard bushings on the frame end.

Click to expand...

Cool. Don't spend a pile on them though. The stock rubber ones are what most leave in there.