Signature or Whiteline Sway Bar? Feedback Wanted!

[jonosx]

I just bought signature bars for my NB8A. No probs fitting them up and they are working fine.

Save your dollars and buy Australian made. You wont be able to tell the difference.

[mitch_f1]

CBF reading the other posts, but Whiteline are now a China (or similar) brand, i.e. not made here any more. Selby swaybars are made up in Queensland still.

I had whiteline swaybars, but I found that when I made the move to stiffer springs (and coilovers) I had way too much understeer. Changed back to stock, and problem solved!!!

I pull this story a lot on my friends, but I know of a guy in Japan who runs one of the fastest street registered S2000 around Tsukuba, and he has done EVERYTHING to his car (minkara: http://minkara.carview.co.jp/userid/672400/blog/) And yet he still has stock swaybars

[lee]

It's not really primary school of even secondary school mathematics, but as engineering mathematics go, it's not particularly complicated. I'm doing this because I'm bored, and I like to know the content I've sweat blood to learn in uni is actually useful

EQUATIONS WE'RE GOING TO USE:
F=kx (Hooke's Law) where F is a force, k is a spring constant and x is deflection.
T=Fr (Torque) where T is torque, F is force and r is the radius at which the force is applied
J=(pi*D^4)/32 (for a solid bar) (Polar Second Moment of Area) where D is diameter
ϕ = TL/JG (angle of twist) where ϕ is angle of twist (in radians), T is torque, L is length of the bar, J is moment of area, and G is Young's (Stiffness) Modulus.

The purpose of a sway bar is to more evenly distribute load from side to side under cornering. In a corner, one side is pushed up relative to the chassis as the suspension is compressed, and the other side is pulled down as the suspension is extended. The force applied at the end link connection can be found by multiplying the deflection of the arm (x) by the bar's k value (which the manufacturer should know)

A sway bar is shaped like a U. The two arms running the length of the car apply a torque to the bar running the width of the car. The length of the arms running down the car can be considered the radius of rotation, r. The force found above can be used in the equation for torque, by multiplying the found force by the length of the arm.

Next is to find the J value. This is probably the most obvious reason why aftermarket bars are stiffer than stock. 20^4 is 160,000 and 24^4 is 331776; an increase of only 4mm can more than double the J value, which as we'll see later, halves the angle of twist.

The only other value which I haven't covered is the G value. This value is the stiffness of the material. Things like Teflon have an incredibly low Young's Modulus (of around 0.5 x 10^9 Pascals), whereas Diamond has a value of 1220 x 10^9 Pascals (1.2 TerraPascals!). A stiffer material will increase the value of G, decreasing the angle of twist.

I wish I learned that in primary school...

[plohl]

Thank you lee - but i was really just trying to see if dann could do the easy calculations himself.

[NitroDann]

Yeah, here they are, you me and everyone else with a primary school understanding of maths can do it.

http://www.fatcatmotorsports.com/FRC_TU ... TORIAL.htm

Also, I did 4 unit maths which comfortably covers the above posted calculations, however I rarely do any complicated maths, so stuffed If I could remember the formulas off the top of my head, Id have to cheat and google those!

Dann

EDIT: In a previous post I quoted the above link to be on solomiatas website, I was on a phone, and didnt have time to google ( ), but 1red5 has put up a whole thread with solo's info.

Dann

[plohl]

pretty sure you said it wasn't complicated though?

[NitroDann]

Its not, read around the site a little bit, or even easier, choose the model of your car and punch the numbers in.

Dann

[manga_blue]

I'd be wary about solomiata's advice. He's into motorkana (and very successfully too) and the requirement is very different from street and track. In motorkhana you load up the front completely by standing on the brakes as you turn in to the cone, rotating the car around the fronts. Then you want both back wheels in contact as you start to put the power on. This means moderate springs for the bumpy lots, very heavy front bars and small or no rear bars. Cars like that have so much understeer on the street that they'd be virtually undriveable.

If you just go by the FatCat spreadsheets to calculate sway thicknesses there are some traps there too. Flatness does not equal grip. Remember that our cars have independent suspension front and rear. As you go bigger with sway bars then you start to couple the wheels more closely. e.g. when the drivers side wheel hits a bump then some of the deflection is transmitted through the bar to the passenger side wheel. With big bars then you're effectively converting your independent suspension into beam axles. So a car with big hollows front and big solids rear has similar suspension to, say, a 1928 Dodge. It'll be dead flat when cornering but have really limited grip on any road or track around this country. What's happening at one side is messing up the contact pressure on the other.

If you set up that way at Wakie then you could be 4 wheel drifting flat through the Fishhook at your tyres' limit while Guran simply drives past you on the inside with his driver's mirror on the pavement. His wheels are working with the track, keeping constant contact, while yours are just skittering.

If you have height adjustable suspension it's much cheaper and easier to change springs than it is to change bars. Tein sell theirs for $120/pr, with dozens of rates/diameters/lengths available. Every time I've changed bars there's been some sort of fitting problem that's made the job take way too long. Springs for me is always about 90 mins all round. Working with springs first means you can get the balance of ride comfort, grip and bounce frequency (= response times) and just fine tune it, if needed, all with slight adjustments or removal of stockish sway bars.

[bootz]

For what its worth, the best thing I did was convert the sluggy 3.6 diff to a sparkling 4.1 torsen 2.
Not a cheap fix but the grin factor immediately went

Stick with the 3.6 only if you want to go forced induction or do long interstate trips.

[NitroDann]

Thankyou for being bothered to write a solid, factual response magna blue.

Also bootz, I dont understand the relevance.

Dann

[bootz]

Thankyou for being bothered to write a solid, factual response magna blue.

Also bootz, I dont understand the relevance.

Dann

Laugh, me too, I just read this and figure must have had two windows open and posted in the wrong thread.

What I meant to say was.....

For the 01+ (NB8B) removing the rear sway would, as some have suggested, reduce low speed oversteer issue. As I love a simple and cheap solution I would like to do this.

Any downsides - handling/ride? I am not looking for race track performance.

[Kenstaki]

Also be aware that this can happen if you uprate the front swaybar:



That's a pic from my NB8A.

How did this happen? How would you avoid it?

[manga_blue]

Also be aware that this can happen if you uprate the front swaybar:



That's a pic from my NB8A.

How did this happen? How would you avoid it?

MY obvious first thought is not to put stupidly big sway bars on in the first place.

FlyinMiata sell reinforced sway bar mounts.
http://www.flyinmiata.com/index.php?dep ... r=13-36600

[bootz]

.

For the 01+ (NB8B) removing the rear sway would, as some have suggested, reduce low speed oversteer issue. As I love a simple and cheap solution I would like to do this.

Any downsides - handling/ride? I am not looking for race track performance.

I suppose the best thing would be try it and see what happens. Seems a simple mod.