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Sweeney921
09-13-2004, 05:54 PM
I was wondering what an anti-sway bar does, where it goes, how it works, etc.....a few pics would help tremendously, since i'm a very visual learner :D

kko
09-13-2004, 05:59 PM
All I know is its purrpose is to reduce body roll, and i think they cn go up front above the engine and in back, not sure though :confused:

Sweeney921
09-13-2004, 06:03 PM
All I know is its purrpose is to reduce body roll, and i think they cn go up front above the engine and in back, not sure though :confused:
I thought it was strut braces that go over the engine :confused:

NAZCA C2
09-13-2004, 06:15 PM
yeah sway bars go under the car strut bars are located on top of the engine and usually in the trunk also. they both make the cars chasis more rigid and decrease body roll.

Sweeney921
09-13-2004, 06:30 PM
sweet, then i'll get one of those babes someday

kko
09-13-2004, 06:32 PM
Ur right sweeny

Sweeney921
09-13-2004, 06:36 PM
I love how everyone misspells my last name

it's sweenEy!

Sweeney921
09-13-2004, 06:45 PM
yeah sway bars go under the car strut bars are located on top of the engine and usually in the trunk also. they both make the cars chasis more rigid and decrease body roll.
where do the anti-sway bar attach to the chassis? they look like they're shaped to attach next to the engine, but deeper under the hood......

Alastor
09-13-2004, 09:27 PM
AS STATED FROM:

http://www.chris-longhurst.com/carbibles/index.html?menu.html&suspension_bible.html

Anti-roll Bars & Strut Braces

- Strut Braces

If you're serious about your car's handling performance, you will first be looking at lowering the suspension. In most cases, unless you're a complete petrolhead, this will be more than adequate. However, if you are a keen driver, you will be able to get far better handling out of your car by fitting a couple of other accessories to it. The first thing you should look at is a strut brace. When you corner, the whole car's chassis is twisting slightly. In the front (and perhaps at the back, but not so often) the suspension pillars will be moving relative to each other because there's no physical link between them. A strut brace bolts across the top of the engine to the tops of the two suspension posts and makes that physical contact. The result is that the whole front suspension setup becomes a lot more rigid and there will be virtually no movement relative to each side. In effect, you're adding the fourth side to the open box created by the subframe and the two suspension pillars.

http://www.chris-longhurst.com/carbibles/images/brace1.jpg http://www.chris-longhurst.com/carbibles/images/brace2.jpg


- Anti-roll Bars (Sway Bars/Stabilizers)

No, these aren't the things that are bolted inside the car in case you turn it over - those are rollover cages. Anti-roll bars do precisely what their name implies - they combat the roll of a car on it's suspension as it corners. They're also known as sway-bars or anti-sway-bars. Almost all cars have them fitted as standard, and if you're a boy-racer, all have scope for improvement. From the factory they are biased towards ride comfort. Stiffer aftermarket items will increase the roadholding but you'll get reduced comfort because of it. It's a catch-22 situation. Fiddling with your roll stiffness distribution can make a car uncomfortable to ride in and extremely hard to handle if you get it wrong. The anti-roll bar is usually connected to the front, lower edge of the bottom suspension joint. It passes through two pivot points under the chassis, usually on the subframe and is attached to the same point on the opposite suspension setup. Effectively, it joins the bottom of the suspension parts together. When you head into a corner, the car begins to roll out of the corner. For example, if you're cornering to the left, the car body rolls to the right. In doing this, it's compressing the suspension on the right hand side. With a good anti-roll bar, as the lower part of the suspension moves upward relative to the car chassis, it transfers some of that movement to the same component on the other side. In effect, it tries to lift the left suspension component by the same amount. Because this isn't physically possible, the left suspension effectively becomes a fixed point and the anti-roll bar twists along its length because the other end is effectively anchored in place. It's this twisting that provides the resistance to the suspension movement.

http://www.chris-longhurst.com/carbibles/images/antiroll_explanation.jpg

If you're loaded, you can buy cars with active anti-roll technology now. These sense the roll of the car into a corner and deflate the relevant suspension leg accordingly by pumping fluid in and out of the shock absorber. It's a high-tech, super expensive version of the good old mechanical anti-roll bar. You can buy anti-roll bars as an aftermarket addon. They're relatively easy to fit because most cars have anti-roll bars already. Take the old one off and fit the new one. In the case of rear suspension, the fittings will probably already be there even if the anti-roll bar isn't.

KnifeEdge_2K1
09-13-2004, 10:48 PM
just to add to this with a bit of simple physics

many people who know squat about the basic nessecities of suspension layout/geometry/design think that a carbon fibre strut brace or something made out of space age composite materials which costs hundreds of dollars must be better then the oem parts or simpler less expensive parts which costs way less

a quick fact

the rigidity/strength of a tubular structure is dependent on it's length, diameter and material

since my whole point is to prove you dont need space age materials like titanium or carbon fibre im removing the rigidity factor out of the equation since it will be a constant for the original and new part, same goes for length because presumably you're not changing the mounting points

so the last thing which im left with is diameter

the d^4 is a factor of the rigidity function which means if i double the diameter i will quadruple the rigidity as long as the other variables remain the same

now imagine my stock strut or anti sway bar is 1cm thick (diameter), d^4 will be 1
if i double the stock struts diameter it will be 2cm thick and d^2 will be 16

but doubling the diameter will increase weight by 4 times but gives a stifness to weight ratio 4 times better then the original, this can be enhanced even more with another simple modification

easy, drill a hole inside the thicker bar making it hollow, if i were to bore a 1mm diameter hole in my new 2mm bar it will now weigh in just 3 times as much as original but will be 15 times more rigid then stock, this gives a stiffness/weight ratio of 5:1

using a simple derivative of the function you can find the maximum s/w ratio you can get givin a specific outer diameter but ill do this tommorow since im tired

as you can see you dont need a whole lotta money or crazy funky space shuttle material to increase the performance/limits of ur car significantly

Sweeney921
09-14-2004, 04:46 AM
alright, my volvo has a stock anti-sway bar, so i won't be messing with that. looks like a better suspension and strut brace are to get

Blue Supra
09-14-2004, 04:48 AM
Both extremely helpful and solid posts
+1 to both of you!

Matra et Alpine
09-14-2004, 06:08 AM
alright, my volvo has a stock anti-sway bar, so i won't be messing with that. looks like a better suspension and strut brace are to get
What Volvo ?

As said already, anti-roll bars help balance the suspension movement during cornering. So a stiffer bar will help maintain inner wheel contact and hence grip.

Stiffening the anti-roll bar is one of the simplest and easiest improvements you can make for a heavier car. The downside is worse bump handling - and can lead to bump steer - and more effort to turn the wheel.

YOu dont' say where you drive and what you ant to do either.
In some cases REMOVING the anti-roll bar can be an advantage.
Tell us more and you can likely get more focussed advice.

Where's Egg-Nog's drawings when you need them :)

KnifeEdge_2K1
09-14-2004, 02:20 PM
anti sway bar's stiffness is proportional to it's diameter to the 4th power, length, and material's rigidity factor

d^4 * length * RF

a 1 inch bar will be 1*length*RF strong
a 2 inch bar will be 16*length*RF strong
a 2 inch bar with 1 inch hole bored through it will be 15*length*RF strong

a 1 inch bar will weigh pi*0.25*length*density in weight
a 2 inch bar will weigh pi*1*length*density in weight
a 2 inch bar with 1 inch hole bored through it will weigh .75(pi*length*density) in weight

:D

Sweeney921
09-14-2004, 07:04 PM
What Volvo ?
1996 Volvo 850 GLT, I did the egg nog challenge a while ago. :D

thanks for all the help!

NAZCA C2
09-14-2004, 08:12 PM
alright, my volvo has a stock anti-sway bar, so i won't be messing with that. looks like a better suspension and strut brace are to get

All cars have anti-sway bars, usually the stock ones are not very stiff so that you car rides smoothly (smooth and comfortable does not equal fast). If you want to upgrade your suspension it would be a good idea to get aftermarket anti sway bars that are thicker (thicker ones=less body roll) and also get strut braces and a lowering kit to completely transform your car into a good handling machine.

http://www.hrsprings.com/site/frameproducts.html
http://eibach.com/cgi-bin/htmlos.exe/00279.4.6549678334900031078

Blue Supra
09-14-2004, 10:24 PM
getting ahold of some of these would be nice, i dont think ill find a parts supllier that has them to fit my car just coz its soo old. are they easy to make yourself? what material should it use?

Matra et Alpine
09-15-2004, 01:17 AM
1996 Volvo 850 GLT, I did the egg nog challenge a while ago. :D

thanks for all the help!
BIG car, don't take the anti-roll bars off :)

Best advise woudl be to spend time in the Volvo parts counter or a Volvo club and find out the T5 suspension settings and a-r bar thicknesses and try sourcing them. I've followed a T5 on track 4 passengers and REALLY pushing it - a fast, well balanced car for something that big and practical :)


getting ahold of some of these would be nice, i dont think ill find a parts supllier that has them to fit my car just coz its soo old. are they easy to make yourself? what material should it use?
http://www.kalmar-union.com/ click on suspension. Pay for my flight and I'll hand deliver :)

Anti-roll bars not too hard to make as long as you have a samle. Problems can come when you try to use standard steel bar and it's thicker than current mounts, maybe needing even more engineering. Local steel fabricators can help , but getting control over the stiffness isn't that easy and will likely involve a few attempts. Buying off the shelf is easier :)