Custom anti-roll bar sizing?

[sykikchimp]

I've read that the whiteline bars are built specifically to work with the whiteline springs..

How would one go about calculating what size bar would work best with specific spring rates?

What is the specific Goal of an Anti-roll bar? Is it simply to reduce body roll? or is it also used to supplement the wheel rate of the suspension?

Say if I wanted to get some custom sway bars built to work with some higher rate springs.

Help me to understand oh ye gods of suspension tech!

-Charles
s13 240sx..

[Peter]

G'day Charles,

I think the best way to start off is to have a look at the Fact Sheet we have for your chassis together with an article you might find of interest. The links are here:

http://www.whiteline.com.au/docs/fact_sheets/CK_Nissan_s13.PDF
http://www.whiteline.com.au/articles/RH02_00_S13_a.htm

Next, I would go to our web site and have a read through the "Tech Talk - Frequently Asked Questions (FAQ) section - particularly, Swaybars, springs and shocks. A couple of links are here:

http://www.whiteline.com.au/faqswaybars.htm
http://www.whiteline.com.au/faqshocks01.htm
http://www.whiteline.com.au/faqsprings.htm
http://www.whiteline.com.au/docs/bulletins/Hollow%20vs%20Solid%20Swaybar.pdf
http://www.whiteline.com.au/docs/bulletins/010barup.pdf

Maybe you could indicate the purpose of your enquiry and define the outcome you are after from your S13 and we will see if we can come up with a suggested solution.

Peter
peter@whiteline.com.au

[sykikchimp]

I don't have a lot of experience with sway bars, but I have read several books on chassis tuning, and such. I just haven't found any good info on acutually figuring out WHAT is the appropriate sized bar..

I am working on the assumption that since the whiteline bars are built to work with the whiteline springs, when they are matched with spring/dampening rates that are different than those specified, I am not fully utilizing my suspensions abilities.

I run with a set of JIC Magic FLT-A2 coilovers. I currently use the whiteline adjustable bars front and rear. The spring rates are 447.6 lbs/in front 335.7 lbs/in rear. I still feel the car has more body roll than it really should. This car is pretty much a track only car. I'm wondering if my excess body roll could be cured by larger sway bars, or more aggressive spring rates.

I would really like to understand sway bar sizing though.

-Charles

[Wojtek]

Hi,
There is a certain relationship between sway bars and springs and shocks that should be kept, but there is no magic number or formula for that as there are too many variables to consider. We rely on our experience and information available to us such as the the size of the factory sway bar (and factory spring rates) which we use as a starting point. This is then followed up with testing of sway bars with various settings, various spring rates, shock rates, wheel alignment settings as well as suspension geometry such as anti-lift/anti/squat kits. Too little sway bar doesn't utilise its full potencial and there will be excessive body roll. On the other hand, too large sway bar and its effect of reducing wheel independance can prematurely overcome tyre grip. This is with an extremely large sway bar, where we always keep on the lower side of this limit for road cars using road tyres. This extensive testing will determine both the size of total sway bar roll resistance an its front and rear split.

Wojtek.