Joined

·
217 Posts

*what would be the difference between these two bars?*I plan on using urethane pivot bushings and end links.

1 - 9 of 9 Posts

Joined

·
217 Posts

Joined

·
1,614 Posts

Mustang Anti-sway Barsmiracerros said:How much difference will it make if I install a slightly thicker sway bar?

A number of factors determine the stiffness of a sway bar, including the bar's thickness and length, the length of the swing arm or lever, the bar material, and the bar's attachment method. But if two sway bars differ only in their diameters, all you need to know is that their relative stiffness (torsional rigidity) is proportional to the 4th power of their diameters. A small increase in diameter results in a large increase in sway bar stiffness. You can caclulate the actual percent difference in the stiffness using the following formula:

larger bar diameter4/smaller bar diameter4 * 100 = percent change in stiffness.

What if one or both of the bars is hollow? That adds one more step to the calculations. After you have calculated the rate of the hollow bar based on its outside diameter (o.d.), you have to subtract the rate of a hypothetical bar that matches the inside diameter (i.d.) of the space within. To do that, you need to know the wall thickness of the hollow bar.

I'll illustrate the above by comparing three stock Mustang rear sway bars: a 21mm solid bar (1996 V6 Mustang), a 24mm hollow bar with wall thickness of 3.84mm (1998 GT Mustang) and a 27mm hollow bar with wall thickness of 5.4mm (1998 Cobra). Here are the calculations:

The V6's 21mm solid bar has a relative rate of (21^4) or 194,481

The GT's 24mm hollow bar has an i.d. of 24 - 3.84*2 = 16.32mm. and a relative rate of

(24^4)-(16.32^4) = 260,838

The Cobra's 27mm hollow bar has an i.d. of 27 - 5.4*2 = 16.20mm. and a relative rate of

(27^4)-(16.20^4) = 462,566

Conclusions: The 27mm Cobra bar sway bar has about 2.4 times (462,566/194,481 * 100 = 238%) the stiffness of a 21mm V6 sway bar and about 1.8 times (462,566/260,838 * 100 = 177%) the stiffness of a 24mm GT sway bar.

Joined

·
217 Posts

solid bar (28.5^4) or 659,750...

hollow bar 28.5 - (4.8^2) = 23.04

(28.5^4)-(23.04^4) = 377,957

659,750/377,957*100 = 174.6

...Not sure if i did this right, but does this mean that the solid bar is about 1.7 times stiffer than the hollow bar? somebody wanna check my math?...lol.. and which bar would you recommend with 1000-1200lbs front springs,Koni sportDA struts, MM c/c plates..on a full weight 1990 gt..

Joined

·
4,321 Posts

First, it should be 4.8 * 2 (4.8 times 2), not 4.8^2 (4.8 squared). Either way, I'm not sure how you got 23.04 - it should be:

solid bar (28.5^4) or 659,750...

hollow bar 28.5 -(4.8^2)=23.04

(28.5^4)-(23.04^4) = 377,957

659,750/377,957*100 = 174.6

...Not sure if i did this right, but does this mean that the solid bar is about 1.7 times stiffer than the hollow bar? somebody wanna check my math?...lol.. and which bar would you recommend with 1000-1200lbs front springs,Koni sportDA struts, MM c/c plates..on a full weight 1990 gt..

28.575 - (4.8 * 2) = 18.975

(28.575)^4 - (18.975)^4 = 537,086

537,086/659,750 = 80.5% (or invert it and the solid bar is ~1.24x as stiff as the hollow bar)

So you get 80% of the stiffness out of the hollow bar, while cutting a significant chunk of weight out of it.

As for what bar to go with, I would suggest something smaller. You're running quite a bit of spring, it doesn't seem to me that it should need a big ass front sway bar, too.

Joined

·
217 Posts

Joined

·
4,321 Posts

Joined

·
217 Posts

Joined

·
1,614 Posts

1 - 9 of 9 Posts

Join the discussion

Ford Mustang Forums

A forum community dedicated to Ford Mustang owners and enthusiasts. Come join the discussion about performance, production numbers, VIN decoders, modifications, troubleshooting, power adders, DIY tutorials, and more!

Full Forum Listing
Explore Our Forums

Popular Communities

Join now to ask and comment!