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  #1  
Old 09-20-2014, 09:28 PM
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Double swaybar

One of the aspects I did not like on the w108 is that it leans a lot in corners. I know it's not a sportscar, and I am not interested in finding out at what point the tires lose traction, but I always wanted more reassuring, flatter cornering.
A w108 showed up at a local salvage yard, so I bought its front swaybar and installed it parallel to the stock one. The only modification I had to make is the use of shorter endlink spacers sleeves to make room for the second bar.

It's still not a sportscar, but it does corner with noticeably less lean.

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Last edited by vandor; 09-21-2014 at 12:44 AM.
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Old 09-20-2014, 10:49 PM
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A creative solution.
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Old 09-21-2014, 07:31 AM
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Never quite understood how sway bars worked, but here is a really cool 3 min video: http://m.youtube.com/watch?v=VoSNAkteXjY

I'm wondering based on the video if the reason your w108 turns better has more to do with a lower sway bar vs. two. Turning would then pop the outer tire sooner?
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Old 09-21-2014, 12:56 PM
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Quote:
Originally Posted by Jub View Post
I'm wondering based on the video if the reason your w108 turns better has more to do with a lower sway bar vs. two. Turning would then pop the outer tire sooner?
What the video doesn't explain is that with pretty much all the cars on the road, the sway bars fitted would not be capable of lifting the inside tire due to body roll alone. By the time the inside tire of a 108 would lift in a corner, there are far too many other things to worry about, such as the need for fresh underwear.

Casaba has effectively doubled the diameter of his sway bar, which should have more effect than its placement. There are other ways of achieving the stiffness gained by adding a second bar, such as cutting out the solid cross section of the original and replacing it with a slightly larger hollow tube, and the tube diameters can be changed to tune the amount of effect desired. (Hollow sways give more resistance than solid ones, apparently, but I haven't watched the YouTube on why)

Another effect of a stiffer sway bar up front is decreased understeer.
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Old 09-21-2014, 03:13 PM
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Provided that both anti-roll bars are the same diameter the roll resistance of the front suspension has been approximately doubled.

Quote:
Originally Posted by Palolo View Post
Casaba has effectively doubled the diameter of his sway bar, which should have more effect than its placement. Another effect of a stiffer sway bar up front is decreased understeer.
If the diameter of the bar had been doubled, the torsional resitance would have been increased by a factor of sixteen(16). Torsional resistance increases as the fourth power of the diameter (2^4=16).

Just as increased roll resistance at the rear of a car makes it looser (oversteer), so increased roll resistance at the front makes it push (understeer). Increased front bar =
Increased understeer.
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Old 09-21-2014, 08:50 PM
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>Hollow sways give more resistance than solid ones,

Not true! It's just that the stiffness of the bar is related to its diameter to the 4th power (as stated above) so the center does very little work.

The reason a hollow swaybar is better is because one that is just a little larger in diameter than a solid one will have the same stiffness but much less weight.

As far as lifting the inside wheel, that usually happens at the rear of the car, and usually on FWD cars where the back end is quite light. I saw it all the time autocrossing.
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Old 09-21-2014, 09:49 PM
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Looks like I got everything bass ackwards this morning! Sorry!

So much for logging on before the coffee was made...

Shoulda just slept in on a frigid fall morning in Hawaii.
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Old 09-22-2014, 07:56 AM
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Quote:
Originally Posted by vandor View Post
One of the aspects I did not like on the w108 is that it leans a lot in corners. I know it's not a sportscar, and I am not interested in finding out at what point the tires lose traction, but I always wanted more reassuring, flatter cornering.
A w108 showed up at a local salvage yard, so I bought its front swaybar and installed it parallel to the stock one. The only modification I had to make is the use of shorter endlink spacers sleeves to make room for the second bar.

It's still not a sportscar, but it does corner with noticeably less lean.
Very ingenious. Good job! Where did you get those clamps?
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Old 09-22-2014, 09:51 PM
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> Very ingenious. Good job! Where did you get those clamps?

They are universal swaybar bushings, available at most auto parts stores and in hundreds of versions online. These were ~$8/pair from Amazon.
The swaybar is 22mm, which is very close to these 7/8" bushings.
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  #10  
Old 09-23-2014, 07:32 AM
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Quote:
Originally Posted by vandor View Post
> Very ingenious. Good job! Where did you get those clamps?

They are universal swaybar bushings, available at most auto parts stores and in hundreds of versions online. These were ~$8/pair from Amazon.
The swaybar is 22mm, which is very close to these 7/8" bushings.
Thank you very much!

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