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Discussion Starter #1
Perhaps this is a stupid idea, but...I was thinking about asking a local off road shop that does a lot of roll cages and mandrel-bend exhaust about trying to replicate my solid sway bar using tubular steel, since I'm not happy with the few OEM tubular sway bar sizes. He said he might be able to do it depending on the radii necessary for the bends and the size steel we need. So does anyone here know what grade steel is used for tubular sway bars, and what wall thickness might be necessary? The guy at the shop said he could do 1.25-inch diameter, .120-wall chromoly without a problem. Would such a material be good enough? Any input

And my only motivation for such a project would be weight savings for my LX, which is becoming increasingly dedicated to autocross.
 

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your right, hollow bars are much lighter [and exponentionally stiffer]... stiffer to the point your going to be ripping the attachment mounts [be easy on the noobie, I havent exactly spent alot of time under this car... yet]. I did this to my project car and ended up having to the reinforce the sway bar mounts to the rear crossmembers to handle it [plus you are going to need some bushings that will fit and endlinks].

chromoly is probably going to be crazy overkill [and really jump the price on you].

do you happen to have any underbody suspension photos [sorry its not the type of weather I want to be outside jacking my car up].
 

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Discussion Starter #4
Mark M. TCCoA VP said:
You both need to read the tech articles. We have 1 1/8", 1 1/4" and 1 3/8" aftermarket bars out there now. These are solid bars BTW.

Mark
I have read the tech articles, and I have an Addco rear bar on my car now--perhaps you misunderstand my intent. I'm looking for a way to have a bar that's stiffer than stock, but not nearly as heavy as the 1 3/8 rear bar on my car now. A tubular bar would meet both of those requirements.
 

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Bensenvill said:
your right, hollow bars are much lighter [and exponentionally stiffer]...
Ummmm, no. They are lighter, but no stiffer if they are the same diameter. The tubular one might be just a touch softer, but not enough to matter.

Mercutio:
I don't see why this wouldn't work. Give it a shot and report back. If you're going to this much trouble, you might as well make them adjustable. I can't remember exactly how much clearance there is in the front, but if you can make even two mounting points on the bar for the endlink, you would have 3 stiffness settings to play with (both to the back, both to the front, and one front and one back; they don't have to be symmetrical side to side).

In the back, I'm pretty sure there's room for a couple of adjustment points. Or, you can do something like what is shown in the link below, where the end link slides on the sway bar, and is clamped in place. The sway bar in the picture is designed to be attached to the rear axle, and the end links attach to the rectangular frame rails, hence that funky shape. Our bars mount to the body, with the end links to the suspension, but there's no difference in the way they work.

http://www.colemanracing.com/catalog/index.php?cPath=49_1409
 

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Discussion Starter #7
According to the chart in the tccoa tech article, one of the oem tubular bars was a rear bar in 1.04 inches for the rear of the 91-96 NA V6 cars. In 90 the solid rear bar measured .98 inches, and in 97 it measured .94 inches, assuming again that the info from that chart is correct. The chart also says that the 92 V8 car was the sole year for a tubular .94 inch rear bar, which was preceded and succeeded by a solid bar of the same size. Is this information correct? If so, is there a measurable difference in handling between any of these rear sway bars that might be extrapolated to compare a tubular 1.25 bar to a solid 1.25 or 1 3/8?

I'll admit that I'm no engineer, so this project would be solely a venture based on experimentation and guesswork. I picked the 1.25 inch diameter because it's the largest pipe this particular builder can bend, it's relatively close to my current 1 3/8 bar, and there are 1.25-inch sway bar bushings easily available. Whichever size tubing might actually work best, there still needs to be a bushing of a corresponding size available.

And again, the wall size is critical. Does anyone know the wall thickness of the OEM tubular bars, or the type of steel they're made from?
 

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I think sway bars are spring steel. You could look into using a long torsion bar and have splined end links on each end. I have seen really lifted trucks use this method before.
 

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Discussion Starter #9
I've seen that method used on Mustangs, too. One consideration for our cars, though, is that each end of our rear sway bars are lower than the center section to provide clearance, so I'm not sure a straight splined bar would work.
 

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A sway bar is a torsion bar. Some are bent for clearance, some are straight, but they work the same way. The splined ends are just for convenience. They allow easier installation, and you can swap in arms of different lengths to adjust the sway bar rate.

Remember, a sway bar works just like a torsion bar. When the suspension acts on each end differently, the bar twists; it doesn't (or shouldn't) bend. The distance from the center of the bar to where the end link connects controls how much leverage/torque is applied to the bar. That's why to make a bar adjustable, you fab it so that the connection point of the end link is adjustable, closer to the bar (less leverage) equals stiffer, farther from the bar (more leverage) equals softer.

As for the wall thickness, thicker would be better. Not so much to make it stiffer, but for longevity. If 1.25 x 0.120 is what the guy has, give it a shot. If it breaks, do something different. (I know, easy for me to say... )
 

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Any new word on this Mercutio? Have you contacted Addco to see if they might bend a tube bar up for you? I just figured since they already have all of the bends for the front bar then it shouldn't be a big deal for them bend up some tube. I would like to have 1 3/8's front and rear bars in tube...a little less rate, but I would imagine they would weight a lot less than those crazy heavy solid bars.

Russell
 

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Discussion Starter #14
This project never really went anywhere for me. I never contacted Addco because it never really occurred to me that they'd take the time to do this.
 

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This project never really went anywhere for me. I never contacted Addco because it never really occurred to me that they'd take the time to do this.
True....I was just wondering. I have just recently been taking some weight out of the car and was just looking into options.

Russell
 
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