Is the weight distribution listed on the specs page,
for physical mass distribution of the vehicle? Like, not counting the springs…or have the stock spring rates been calculated into this measurement?
Ben, XDEep? Anybody?
Here’s why I’m asking.
Given:
The stock weight disribution is listed as %-62F/38R
The stock weight of the a 3dr GS is 2560lb
The stock spring rates are 263F/143R
Im putting on sportlines, and I’ve used a digital vernier caliper to measure the necessary parts of the springs, both front and rear, and used a calculator to get the spring rates. (assuming 12,000,000 density rating as reccomended by Fred Puhn in “How to Make Your Car Handle”.) you can find the calculator i used here, http://www.engineersedge.com/spring_comp_calc_k.htm
Measurements:
FRONT:
Coil Diameter - 0.522 inch
Inner Diameter (top) - 2.521 inch
Outer Diameter (top) - 3.536 inch
Inner Diameter (bottom) - 2.291 inch
Outer Diameter (bottom) - 3.325 inch
REAR:
Coil Diameter - 0.455 inch
Inner Diameter (top) - 2.387 inch
Outer Diameter (top) - 3.319 inch
Inner Diameter (bottom) - 2.774 inch
Outer Diameter (bottom) - 3.690 inch
To find a general overall diameter take the difference of the OD and ID and add it to the ID.
FRONT-
Top: 3.029 inch
Bottom: 2.808 inch
REAR-
Top: 3.232 inch
Bottom: 2.588 inch
Take the average of these and you will get a rough overall diameter for the springs
Front - 2.919 inch
Rear - 2.853 inch
Now plug that all in the calculator and you get exact spring rates for my particular springs:
Front - 426.6 lb/in
Rear - 296.7 lb/in
Now that i’ve proven my spring rates I’ll use, here is my theory.
Stock NET spring rate (F+R) - 406 lb/in
Stock weight distribution - 62/38 (which i think is really 64/36 and was miscalculated, or the stock spring rates are wrong…)
Eibach NET spring rate (F+R) - 723 lb/in
Eibach weight distribution - 58/42
Heres why i think its this way:
Stock SR - 263/143 lb/in @ 62/38%
if you take 263 and divide by the net SR (406), you get 0.64, which i think is the ACTUAL weight distribution of the stock setup.
Eibach SR - 426/296 lb/in @ 58/42%
using the same technique, by dividing 426 by the net SR (723), you get 0.58. which when subtracted from 1.0 (100%) would mean the rear is 0.42
So, I guess what I’m getting after is, if spring rate varies directly with weight distribution, the Sportlines will change it to 58% front and 42% rear. Cutting down on understeer and giving the DA a more neutral feel.
but then again, it is 2am, and i am quite sleepy. 
edit
I realize the calculator site says to take the OD and subtract the coil diameter, but I think that since these springs decrease in radius as they go down, taking the centerline of the coil diameter and averaging it across the full length of the spring will yeild more accurate results.
I didn’t bother reading all of that, but how does changing springs somehow redistribute weight again?
Your units are inverted on your springrates, by the way.
oops haha, sorry about the units. 
that would be some crappy springs…lol 1 lb compressing 406 inches…lol
But i figured by making the front stiffer than the rear, or vice-versa it would effect the amount of weight being applied to that wheel. It would act like preloading weight fore or aft. I could be wrong (and probably am) and i’d like a good explanation of weight distribution and how to alter it via suspension.
I know stiffer springs in the rear cause Oversteer, and in the front cause understeer. I’m wondering if this oversteer/understeer situation is caused by weight transfer or weight distribution OR a combination of both.
simply, weight distribution can only be changed by altering the weight over any given wheel, not by changing the spring rate. you will affect weight transfer under load though.
you can make the front or rear stiffer, softer, raise and lower ride height, and all these factors (plus many others such as damper quality) will alter how the car handles and behave under cornering loads and weight transfer. the actual handling envelopes (what’s happening while under cornering/braking/accelerating load) are what you want to fine tune.
tbh, suspension is very much a black art, and unless you’re an expert in the subject, i’d simply save a lot of time and effort and go with a proven setup, or certainly not stray too far from one
i’ve spent hours and hours on the internet researching different setups, suspension behaviour, front and rear bias setups etc (lot of threads on H-T re this), and have had about 4 different setups in the last 2 years. Guess what? I’ve ended up with Eibach Sportlines 460lb up front, custom linear rears that are about 400lb (stiiffer thean the std Eibach to give sharper turn in), and Koni Yellows.
So pretty much a fairly std, well proven setup for a daily driven / occasional circuit weapon. I could have saved myself a lot of time and effort though… :bang:
Thats awesome!
So weight transfer > weight distribution on the importance scale.
And hey, I’m all about doin stuff wrong and learning from my mistakes. All that costs is time and money. If it takes me 10 years to get my setup right, then its gonna take 10 years. hopefully the car will last that long…
I installed the Eibach’s yesterday. I had a problem though.
The DA’s rear dampeners, when fully tightened with the eibach’s, allowed the springs to jiggle around about 2 inches inside the perch and underneath the hat. This was unacceptable to me, because if i hit a bump or hill and my wheel came off the ground, id run the risk of jumping the spring off the assembly!
So what i did was warrenty out the DA monroe’s for some from a stock DC2. The body of the strut was the same length, but the piston was the exact length shorter that i needed. Worked perfectly!