Overbear

I have not had it out to autocross day yet, but from playing around a bit in the hills, and in a parking lot on a Sunday. It digs in nicely, I have almost NO understeer and that surprised me.

Now part of it is, I am only using 6 inch coils in the front, but 7 inch out back. I have found that the shorter coils, compress less (duh, shorter) so the front end wants to plant and stay pretty much to the limit of the tires. The rear does want to lift some and shift the GC forward, but not nearly what you would think.

My big problem now is body flex, I need to save up and put in T braces, center braces, front H brace and a few other goodies to keep her from wanting to torque the crap out of the body.

joltdudeuc

iTrader: (6)

I think it's just way too hard to know how strong the bar really is with such language.

I've learned ft lbs/in makes it a level field but no one markets that way.

Lowend

iTrader: (5)

I can ask Myles what the rate of the bars are.
Bear in mind that while solid bars are stiffer than hollow, the degree to how much is dependent on materials and the wall thickness.
All things equal, the rate of a swaybar goes up by the cube of the diameter. Little changes make big differences

k-dogg39

iTrader: (7)

I get it also. This was heavy braking. I definitely had too low of tire pressures as well here.

joltdudeuc

iTrader: (6)

I've tried to reason about this, and keep concluding that it can't be all that different. Though I would love to test several bars and put it to rest, I've found that thinking solid bars give small gains in bar rate.

22 vs 24 doesn't make the 24mm bar way stiffer. It is stiffer, but not really all that much. Take my bar... You'd think my car is wildly tail happy but it isn't.

Its perfectly smooth in engagement and it just doesn't make the car too tail happy. It just works.

JelloChex

iTrader: (6)

While this particular example is using the GR models for the basis of the comparisons this is probably fairly comparable as to the given numbers. In this case the Whiteline bars are not represented on the chart, but being that the Perrin bars are offered as Solid Bars those can essentially be used as an alternative to the Whiteline bars to express the point.

Springs, Swaybars, Wheel Rates and Frequency - Subaru Impreza WRX STI Forums: IWSTI.com

joltdudeuc

iTrader: (6)

I'm not sure why such calculations are needed. He's using a formula to calculate the bar rate based on known MR and spring rates.

How do you find out the spring rate of a spring? Apply weight until it compresses 1"

Same thing with a sway bar. Mount it and then apply weight to one end until it flexes 1", now you know the force it takes to get a ft lbs/in measurement.

This makes far more sense to me.

Every bend in the bar weakens it considerably, which is why a straight bar with arms perpendicular to it gives you the strongest resistance.

I think if I can collect several bars I'll get them measured.

Lowend

iTrader: (5)

The great frustration of building a suspension:
Manufacturers don't want to publish specs. Its pulling teeth to get spring rates, I don't think any easier to get sway bar rates.

TheFozz

iTrader: (2)

This topic's giving me a headache now.

"The angle of differentiation of the dangle is directly and conversely proportional to the deflection of originality in the activator's turning radius..."


Cripes, just drive (hammer) on the thing and enjoy it?

Lowend

iTrader: (5)

If anyone wants to take some measurments
swaybar.xls

joltdudeuc

iTrader: (6)

Far too simple.

Each bend in the bar weakens it. This also doesn't take into account metal quality or metal tinsel strength.

This why I feel you have to literally apply force to a mounted bar and see how much weight it took to move 1"

mattsn0w

iTrader: (23)

That look when you lift a cheek to fart. ;D

k-dogg39

iTrader: (7)

exactly!

TheFozz

iTrader: (2)

ftfy.

wombatsauce

iTrader: (7)

I always dreamed of constructing some sort of "jig" for testing sway bars. It would have adjustable D brackets for the body-side mounted to a bench, then adjustable links at either ends on positionable legs, where you could apply force on one end of a sway-bar (say with a hydraulic bottle-jack) and using some sort of pull-scale on the other end of the bar, measure how much force was transferred. Obviously I have not thought it through completely, just an idea bouncing around in my head.

Mostly this was to see the difference between force applied using different holes on an adjustable unit - but - if the mounts were done right, it could be used to create a basis of comparison for sway bars. I feel like this sort of basis does not currently exist.

If you think about it, it's just a torsion bar with levers on each end - so, the bends do not necessarily weaken the bar, but rather, change it. I get what you are saying - I am not arguing - but I am saying that it would be interesting to see how a bar with bends compares with a bar that has the whole length of "spring" available for torsion. As long as the bar is not weaker at the bends themselves, the bends effectively remove a portion of the spring.

I could be way off.