I was wondering if the slant six community would be interested in a step by step for making custom front and rear sway bars. I'm probably starting them in a month or so.

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1965 Plymouth Belvedere II Turbo Project - SOLD
2002 Subaru OBS
1995 Lexus LS400 Race Car

Tec on making our rides perform better is always welcome.

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Fast is fine but accuracy is final. You have to learn to take your time ... in a hurry
- Wyatt Earp

Go for it! Will you be using NASCAR-style splined tubular bars and arms, or??

Have fun,

Lou

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Home of Slant6-powered fun machines since 1988

I'm still deciding on the design. For the front I was thinking about using 1 1/2" solid bar, and heating/bending it. The ends would be grinded down to flat and have multiple holes so it can be adjustable. Or I was going to try the nascar style setup. The car is being built for drifting, so the stiffer the better. I will have it sorted out within the next couple of weeks.

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1965 Plymouth Belvedere II Turbo Project - SOLD
2002 Subaru OBS
1995 Lexus LS400 Race Car

drifting you say, I like where this is going


-Mike

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I am the Guardian, I hate helos, everything leaks.......

Yeah, I didn't think I'd get any interest, turns out there is a couple people here that are stoked to see it!

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1965 Plymouth Belvedere II Turbo Project - SOLD
2002 Subaru OBS
1995 Lexus LS400 Race Car

I would only be interested if it is tubular and not super stiff. 1.5" is 1.5-3X stiffer than what I would want. I have used a 1.25" solid bar and a tubular 1.25" and 1.125" solid. The 1.25" solid was quite stiff. I could see maybe a 1.25" or 1.375" tubular with 1/8" or 3/16" wall.

Lou

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Home of Slant6-powered fun machines since 1988

Yeah, I want to try the 1.5" solid. Stiff is what I need! But even just the steps I did to make it might help a lot of members out.

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1965 Plymouth Belvedere II Turbo Project - SOLD
2002 Subaru OBS
1995 Lexus LS400 Race Car

Fair enough!

Lou

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Home of Slant6-powered fun machines since 1988

If a one piece sway bar is the goal I would use 4130 tube, I would use the smallest radii die that you can get (likely about 3X the tube OD), I would bend it cold, and I would make the attachments for the links clamp on. By clamping them on you can slide them along the 'lever' part of the sway bar for infinite tuning.

A long time ago I looked at torsional stiffness in tube vs. solid bar for use in drag race steering input shafts. My conclusion was that the middle third of a solid bar is just extra weight, it does very, very little for torsional stiffness. So let's say it's a 3/4" OD tube. For torsional considerations the max realistic wall thickness will be 1/4" Any wall thickness greater than that gains weight for no real increase in torsional stiffness. 3/4" was exactly the OD that I looked at, no idea how this scales. I suspect linearly or pretty close to it, but have no data points.

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Thom

Cross-threaded is tighter than Lock-tite

Would clamping not slide around from hard driving?

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1965 Plymouth Belvedere II Turbo Project - SOLD
2002 Subaru OBS
1995 Lexus LS400 Race Car

And if I'm using a solid bar, there is no wall thickness? I'm confused by that second paragraph.

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1965 Plymouth Belvedere II Turbo Project - SOLD
2002 Subaru OBS
1995 Lexus LS400 Race Car

[quote]My conclusion was that the middle third of a solid bar is just extra weight, it does very, very little for torsional stiffness[/quote].

That would be correct, top & bottom outer surface of [url=http://www.bing.com/images/search?q=parts+of+an+I+beam&qpvt=parts+of+an+I+beam&FORM=IGRE#view=detail&id=3F03B4332E7E1F4CCA4BDC3DDA34AB2643099F8F&selectedIndex=21]structural member[/url] carries the load be it compression tension. This is why an “Iâ€￾ beam or [url=http://en.wikipedia.org/wiki/Open_web_steel_joist] “Jâ€￾ section joist[/url] has very little material between its flanges. The more distant from center line of member (zero tension & compression) the greater the loading forces become. No discussion of shear or other forces being considered in this example.

Diagram of structural member above is of a point load not cantilevered (attached at one end) as the end of a sway bar would be for a “momentâ€￾ analyses, but the one can see that the upper surface is being squished together (in compression) while the lower surface is being stretched (in tension).

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67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC

Not if the clamp's bore is sized correctly. Have a look at the two piece "shaft collars" on mcmaster.com to see how they should be designed. I don't think that you will want to use those as they're pretty spendy, but they are a good design to copy for this use.
Let's say that you are using a 1.5" OD bar. The difference in torsional stiffness between a solid bar and a tube with 1/2" thick walls will be so small as to not be worth the significant increase in weight. My suspicion is that 3/8" walled 1.5" OD tube's torsional stiffness is very close to being the same as the 1/2 walled tube at yet even less weight.

WJA: I was only looking at the section of the bar in torsion. I have not looked at the "lever" sections for bending strength as I did not feel that it was needed.

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Thom

Cross-threaded is tighter than Lock-tite

Those collars will work amazing actually, think I might use the aluminum ones. And so I should find a tube with 1/2" wall thickness? I'm looking at designs for a nascar style one as well, which will make adjustability a lot easier imo.

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1965 Plymouth Belvedere II Turbo Project - SOLD
2002 Subaru OBS
1995 Lexus LS400 Race Car