Evo_Someday

The whiteline 26mm front sway I have now, according to their website and other info I find, is 38% stiffer than stock.

Ok great. But I do some looking around online and and find out...

Cusco 25mm front = 123% rate increase.

Swift front = 118% rate increase.

So this confuses me. Does this mean that Whiteline is only like 1/3 stiffer than the stock bar but Cusco and Swift are more than DOUBLE the stiffness of the stock bar despite being thinner than the whiteline?

OR -- does it mean the Cusco is a literal 123% of the stiffness of OEM -- as in OEM = 100% and this is 123% so therefore only 23% stiffer.

I think this makes more sense to me. Thoughts? I really need some help on this.

griceiv

iTrader: (2)

I think you answered your own question.

there is no way that 1mm increase in bar diameter is going to result in double the rate while simultaneously have the stock drop links work.

a 1mm diameter increase does support roughly 18% increase (or 118% of stock) with no change in arm length.

Dallas J

iTrader: (1)

This, 23% stiffer and 123% stiffness would mean the same thing. Its just wording to confuse you

Evo_Someday

Well it worked.... Just wanted to make sure. Thanks.

I'm running the whiteline 26mm front with KW coilovers and feel like I'm STILL leaning over. Of course this is with big 285 sticky tires while hauling butt....



I was hoping to find a 27mm or maybe even 28mm front sway to see what happens but those are not options so I'll need to get creative.

Dallas J

iTrader: (1)

What spring rate? Im finding the same thing with 700 front spring and a whiteline bar. Ive got some ideas for changes but still gotta do some testing to see if it works.

Evo_Someday

I don't recall the spring rates. I'll check tonight when I get home and post.

Feel free to share your ideas.

Dallas J

iTrader: (1)

My ideas stem from some things Grice has said and watching their car. But the biggest for the math folk in the room, Does balancing natural frequency mean squat when you have two completely different suspension with different roll couples, and tires with different weight/width.

Then add into that the fact a car doesnt have 4 masses, one on each tires, but a single mass that gets thrown around based on an acceleration provided by each tire. While turning, your static natural frequancy balance is all eff'd.

So, where to go from here. Reduce load on front outside tire, increase load on front inside tire. Ill let you ponder what gets this to happen, but will say I'm going to move in a different direction as you

griceiv

iTrader: (2)

it means the same as it always does. you can improve how the car responds to bumps...that's about it.

turning has no effect on your natural freq's. sure the loads change on each corner while turning but the mass supported by each corner does not change.

Dallas J

iTrader: (1)

Ive had to think about this for a bit and ill need to think about it some more but I think I disagree.

If NF = sqrt ( K/ M) and F = M * A, then NF = sqrt ( K / ( F / A)) = sqrt ( K * A / F).

We know K and A are constant but force is not. Force is changing with weight transfer and roll (sway bar becomes a spring as well). Ill spend more time looking at the math (proof for N.F., break it down a little further) but pretty sure N.F. is not a constant.

Evo_Someday

In reference to what you see happening to my red evo in the picture above.. My spring rate is 140 newton/millimeters

Since KW does spring rates in n/mm I'll convert = 799 pound/inch = 14.26 Kg/mm

They just don't seem to be enough. KW sells springs that fit in the following options.

150 n/mm = 856 lb/in = 15.2 Kg/mm --- would be a 7.1% increase
170 n/mm = 971 lb/in = 17.3 Kg/mm --- would be a 21% increase
190 n/mm = 1085 lb/in = 19.4 Kg/mm --- would be a 35% increase

Evo_Someday

You could design a hydraulic shock system that retracts the front inside wheels and extends the outside wheel thus causing the car to lean to the inside of the turn like a motorcycle.... :-)

griceiv

iTrader: (2)

Do you really think A is constant when you're turning? I'm pretty sure K and M are constants, unless you're car goes WAY faster than mine does. (theory of relativity?? )

Dallas J

iTrader: (1)

Good point, I was thinking of gravity only but if you only consider steady state since thats what you'd setup springs/bars for anyways then yes at that moment A is constant.

Hah, we know my car isn't near yours (yet?? ) Really though, the idea of motion ratios constant or not doesn't really matter if you're making a change and measuring the results. Iteratively improving, on that front I'm like 5 years behind you guys

griceiv

iTrader: (2)

if you compare this photo with your photo the only major difference I see is your car is much higher than ours. hint: there are two factors that determine roll angle. Roll stiffness and roll moment.

Evo_Someday

You just made my head explode.

All I know is.. roll center correction kit -- I installed it but nothing tells me at what ride height the roll center was designed to be optimal.

I also just read an article on roll moment in relation to roll center, etc. But so what? How do I use this information to make the car handle better? What's the goal?