DamonB

No. Only the rear sway bar was softer. Spring rates were the same on all models.



Correct.

t-von

iTrader: (8)

Thats right I completely forgot it was the shocks and softer sway bar that were mainly changed.

Howard Coleman

iTrader: (6)

progressive rated springs are wound in a manner that changes the linear rate as the spring is compressed.

just so there is no confusion, linear springs DO increase rate w compression. for example, a 400 pound spring requires 400 pounds to compress it one inch, 800 pounds to compress it 2 inches and 1200 pounds to compress it 3 inches.

a progressive spring might require 200 pounds to compress it one inch and 900 pounds at 2 inches.

real non-ground effects racecars don't use progressive springs generally as they are much harder to drive at the limit as the huge change in rate happens all of a sudden in the middle of a corner when you have all you can do to keep the car balanced on a knifedge.

suspension engineering for sports cars should be all about being linear..... steering, body roll, spring rates etc. that is one of the FDs most valuable qualities, the linearity of it's drivability.

BTW, there is a mis-statement on Eibach's website as to the Pro Kit springs being progressive. Eibach's tech guy told me that they are not progressive and the statement should be corrected. my digital spring checker also corroborates.

finally, back to the theme of the thread... here's some additional spring data:

Tein

S Tech coil springs front drop 1.4 inches rear 1.3 inches rate front 440 rear 320

High Tech coil springs front .8 rear .7 front 390 rear 290

Tein coil overs

Flex front spring rate 560 rear 450 ( i consider this the edge of streetable spring rate for the FD but acceptable.) this is my favorite coil over package for the FD.

Eibach Pro Kit 1 inch drop front and rear rate 350 fr and 255 rear.

do not discount the non R1 OEM shocks. they work very well w the Eibach Pro Kit springs and the Tein H Tech. i recommend anyone wishing to upgrade their handling do springs first, realign car, and then drive their FD for a while. chances are you may decide you don't need aftermarket shocks..


howard coleman

DamonB

No, they do not increase in rate with compression. A linear spring with a 200 pound rate means it will resist each inch of travel with 200 pounds. 1" =200 pounds, 1.5" =300 pounds, 2" =400 pounds, etc. The rate at which the linear spring provides a resisting is the same no matter what the weight placed on it. The amount of resisting force the spring provides varies in a direct and linear relationship with the amount of compression and thus the rate is constant ("linear").

If you were to draw a graph and plot resisting force of the linear spring vs. compression of the spring your results would give you a perfectly straight line ("linear") with constant slope. That slope would be the rate of the spring.

If you were to plot the results for a progressive spring you would not get a line with constant slope but rather one that changes in slope along its length and results in a curve. If the slope increases with additional weight then the spring is a progressive type. If the slope decreases with additional weight then the spring is anti-progressive (impossible with a plain coil spring but possible if using pushrod suspension).

Mahjik

iTrader: (1)

I would like to add that the "advertised" drop numbers have typically been different than the actual drop.

In my experience, the Eibach's dropped the front much lower than 1" and the Tein S-Tech dropped a little lower than advertised as well. Many others have commented on the Eibach front drop as well.

Endless Work

Now from the techs at Japan office for Endless, they've spent a lot of time putting varying spring manufaturers springs on a dyno to see the results of whether they are truly linear. You would be amazed at the results. For all intensive purposes from what i understand, even a linear spring will deviate ever so slightly from it's "printed" spring rate. It most likely will increase a little compared to the progressive rate which would change drastically.

I started researching this more when endless released their X-coil. Read this excerpt:

"For the next generation hard user, we’ve developed the Function-X Series. The Function-X is now born. With advanced damping capabilities in effect, our efforts have recently focused towards our new “X-Coil Hyper Spring”. Through consistent and progressive research and experience, we’ve improved spring quality to achieve an even smoother and more responsive feel and ride. The ability to grasp precise road data has improved. The X-Coil spring achieves exactly this. Our Dynamometer Data proves this with stable rebound and compression levels (within a 0.1 Meter Per Second range) for level travel at very low speeds, very high speeds, and everything in between. By keeping very detailed, precision spring motion in mind, we are able to set the shock’s piston valving to superior levels. The combination of the shock and spring is superior. Our Linear Spring Motion with no Friction Loss is superior and the shock can be adjusted very precisely (Function-X includes 30-Way Damping Adjustability), thus the setting levels have broadened and can be fine-tuned with advanced precision and feel. Lightweight aluminum upper mounts, spring seat preload and spring seat locks, height-adjustable lower brackets and lock seats (for non-strut type applications) include a durable, Alumite finish for rust proof characteristics. Steel shell casing includes a special chromate plating for rust proof characteristics also. Adjustable brackets are newly designed and slender. Driving feel is amazing for the hard-user. MacPherson Strut-Type systems are specifically produced as an inverted-monotube type."

Email endless usa if you would like to be on the mailing list. They are always shooting out new info on technology.

Endless Work

This isn't an OE style spring, so it's only relative in the sense that it shows data and implies that other springs can vary from the "ideal" if stated to be linear.

DamonB

At least the marketing waited until page 2 this time...

Endless Work

lol. You are free to edit it Damon so that it's not marketting. I didn't indicate anything other than this excerpt. feel free to do what you need to. I did email your admin btw, but never received a return pm. This was well over a week ago. Most likely two weeks ago. I just need a number, a reasonable number hopefully.

Please contact him again and ask him to PM me so I may take his offer to our superiors.

Thanks.

DamonB

I did and you're welcome. If it's no problem with them it's no problem with me.

BOOSTD 7

You never contaced me, I'm pretty easy to get ahold of. Either ryan@rxtuner.com or 314.780.2792

Endless Work

I did reply to your PM boostd. guess it was not received. I'll pm you again.