Control arms?

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Control arms?

Postby critter » Tue Jun 01, 2010 8:08 pm

Here's my delimma.

I purchased a bunch of front suspension parts for my 1974 Trans Am a while back. This was before I took more of a pro-touring turn with the car. So now I have a 4L80e and paddles from Twist and I want to take advantage of it on an autocross or 2. I can't really afford tubular control arms right now but I do have Del-a-lums and GW offset cross shafts for the upper control arms. That might help a tad.

So my question is, is there any way to strenthen the stock controls arms with welding in supports or is it even worth it?

What else should I do as I pursue the front suspension rebuild?

Oh, the car already has polygraphite sub-frame bushings and sub-frame connectors.

And just how bad are the stock control arms?
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Re: Control arms?

Postby caramaro » Wed Jun 02, 2010 1:41 pm

i'd wait and get the tubular control arms. you just can't go wrong with them. did you upgrade your brakes?i can't remember... did you add a sway bar?
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Re: Control arms?

Postby critter » Wed Jun 02, 2010 2:31 pm

Yep, brakes are the all disc with 1LE 12 inch fronts. It stops a LOT better these days. The TA came with front and rear sway bars so that's covered. Most everyone agrees it seems. The stock arms are fine for my use.
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Re: Control arms?

Postby Vanmor » Thu Jun 03, 2010 1:32 am

I know this sounds like redneck engineering, but it seems you could weld in some tubing or solid rod in the A arm recesses. Will add some weight though.

I'm going to reinforce my rear arms by welding in some square tubing.

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Re: Control arms?

Postby caramaro » Thu Jun 03, 2010 2:12 am

i know some people go with a thicker than oem sway bar
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Re: Control arms?

Postby critter » Thu Jun 03, 2010 8:12 am

I had considered drilling 1 inch holes in the arms and putting 1 inch tubing through the holes and welding them into place. But after talking to a lot of folks over the past few days I'm about convinced the payoff of rigidity VS weight is just not worth it. Most seem to agree that I'll find other limits to the suspension long before I need to address the issue of stock control arms and flexing.

I do need to figure out what size the stock sway bars are. I have them, front and rear, but they are factory spec. So far they have done a fine job but I'm thinking those and springs may be the first things to show the effects of having sticky tires.
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Re: Control arms?

Postby 77TA » Thu Jun 10, 2010 5:18 am

Id give it a time around the cones before changing anything. The car looked pretty good in the pictures.
I think it kinda depends on how hard you will push it. On an autocross course you may be just happy as can be with it as is at least for a while. I went stiffer on the springs and it seemed to tighten the feel of the car up and made it more stable at higher speeds..but probably not night and day from where your at now.
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Re: Control arms?

Postby critter » Thu Jun 10, 2010 5:51 am

That's what I have decided to do. I had a lot of feed back from people saying that, other than improved geometry on "some" tubular arms and the weight savings it wasn't worth it. Most folks pointed out that the factory setup on second generation Trans Ams was pretty darned good as delivered.

I also looked up the sway bars sizes. The front is 1.25 inches and the back is roughly a 13/16 inch so those are pretty beefy to begin with.

I now have all the bushings and stuff I need to start rebuilding the front end. Once I fix the speedometer I should be able to start looking at this project.

In the heat of July.

Yippee.
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Re: Control arms?

Postby lmd » Thu Jun 10, 2010 10:52 am

critter wrote:That's what I have decided to do. I had a lot of feed back from people saying that, other than improved geometry on "some" tubular arms and the weight savings it wasn't worth it. Most folks pointed out that the factory setup on second generation Trans Ams was pretty darned good as delivered.

I also looked up the sway bars sizes. The front is 1.25 inches and the back is roughly a 13/16 inch so those are pretty beefy to begin with.

I now have all the bushings and stuff I need to start rebuilding the front end. Once I fix the speedometer I should be able to start looking at this project.

In the heat of July.

Yippee.


The only way you see any weight savings on a fixed a-arm is if they are made out of chrome-moly, if they are made out of steel some are actually heavier while others are only 1-5lbs total.

I know that fixed CM upper, lower a-arms, spindles, and aluminum steering arms are 36lbs lighter then the stock stuff. A pinto rack, bump steer kit, and CM steering rod is 25lbs lighter then the stock steering, but there is a reduction in steering radius.

Image

Of course all this has a different geometry built in due to its intended purpose compared to the "turning" stuff that its out there.

http://www.speedwaymotors.com/Chrome-Mo ... ,4853.html

http://www.speedwaymotors.com/Speedway- ... ,4911.html

If I ever get around to putting my 80 TA back together, I'm thinking of using the upper control arm from link #2. The only way out there to change the geometry with these GM subframes is with the upper control arm and spindle.
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Re: Control arms?

Postby raybs » Thu Jun 10, 2010 2:26 pm

If you do change it out - change everything as a kit. I did the Hotchkis uppers and B-body spindles in the GTO and while it handles MUCH better out on the road, :mrgreen:it changed the geometry enough that the centerlink hits the oil pan when attempting small-radius parking lot maneuvers. "brickwall"Thus, it has the turning radius of a Mack Truck. So, whatever you do, it all has to work together.
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Re: Control arms?

Postby critter » Thu Jun 10, 2010 3:25 pm

You're the second person to say that.

Pro-touring F-body has some nice suspension kits but at this point a solid rebuild with Moog parts, Del-a-lum's up top and the offset cross shafts is where I'm going. I want the car to be comfortable but sporty. Everyone I've talked to regarding those requirements agrees that my plan is sound.
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