Vano- Stiffer sway bars, as earlier stated, usually will not increase grip at any corner of the car. If they do, it's only because the suspension's camber gain during compression can't effectively counteract the body rolls addition of positive camber (to the outside wheels of course), meaning a sitffer sway bar increasing effective cornering load on the outside tire, but also increases the contact patch size enough to have a net increase in grip on that axle. Other than this example, sway bars will only decrease traction available on the axle, due to the non-linear relationship of tire grip vs. tire load. Without getting into the effects of different roll resistance at each axle vs. the need for the car's body to roll at a single angle (this gets really complicated, and will account for some longitudinal weight transfer), here's a quick example of how sway bars work to tune the chassis balance in a corner...

For this example we will use a sway bar with a roll stiffness of 250 lbs, on a 4000 lb car with a perfect load distribution to the tires:
Left front static load: 1000lbs
Right front static load: 1000lbs

-lateral weight transfer in a right hand turn @ .5g cornering force
Left front: + 500lbs
Right front: - 500lbs
Total weight transfer: 1000lbs

-effective load transfer of sway bar (which is 250 lbs):
Left front: +250lbs
Right front: -250lbs
Total weight transfer: 1000lbs

-total effective cornering load for this example:
Left front: 1000 + 500 + 250= 1750lbs
Right front: 1000 - 500 - 250= 250lbs

-without sway bar
Left front: 1000 + 500= 1500lbs
Right front: 1000 - 500= 500lbs

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Now understand that as a tire's load increases, it's grip increases. But this relationship is NOT linear, you can only push a tire onto the road surface so hard before it's grip ceases to increase. So on any given axle of a car, grip will be highest when the total tire load is evenly dstributed to the tires. So as you increase the load split between two tires on an axle, the total avaialble grip actually goes DOWN. This is why adding a stiffer front sway bar to the S2k increases understeer, as the front end now has less total grip available than before.


Ps- Touring cars are a whole different ball game, the suspensions are specifically designed for their intended use. The roll stiffness is designed to both increase driver confidence (a hugely important thing to consider in sway bar effectiveness) and control the speed of weight transfer during corner entry. Hope this helps explain things, peace.

 

Thanks for the explanation!

I am starting to understand what you guys are talking about now.

I guess the point of the sways is mainy making the handling more neutral, making the car more contorlable and getting better driver comfort (agressive driving comfort anyhow).

Its starting to make sense how the the huge mugen bar upfront can cause more understeer...yet even though the bar makes the traction lower in the front most people still go ahead and get it. My guess is, overall you can still drive faster knowing that the car is not gonna snap-oversteer on ya.

does any1 know if any changes in the rear suspension will aid bump steer?

 

After reading this very informative post on sway bars, I have to say I was confused at several points. But, the bottom line is exactly what vano summarized. The car's handling is more neutral with the bar.

I have the 31.8 mm Front Mugen bar, and I have to say the car is more predictable. Not only in the body roll decrease a bit, but the car handles so much better now. Before, the car's back end would come around if I wasn't careful. Now, with the bar, it tracks effortlessly around corners. The front tires will start to break loose and make noise, but it never really starts to understeer. It's simply more balanced. The bar inspires so much confidence. The back end seems firmly planted no matter how I drive.


Here's my writeup on the Mugen install
http://dbkelly.hn.org/s2000/MugenSwayInstall/index.htm


David