Spring Comparision

[dank24]

I need pictures for my ADD

[HEMI-Fit]

Originally Posted by Evil XT

Did anyone find the OEM spring rates?
I cant find them anywhere..

Well, I got a set of stock springs (and struts/shocks) in the other day, and today I finally had a few minutes to take some notes and measurements. Here's a breakdown of what I found, along with the results of my spring rate calculator:

Front Springs

Outside DIA = 5.5"
Wire DIA = 0.455"
# Free Coils = 5.5
Calculated Spring Rate = 111 lb/in

Rear Springs

Outside DIA = 4.25"
Wire DIA = 0.415"
# Free Coils = 5.0
Calculated Spring Rate = 158 lb/in


I still have to do a reality check on these calculated rates by putting them in my press and seeing what they say on a scale. The formula, for those interested, is:

Rate = [(G)x(d^4)] / [8x(n)x(D^3)]

where

G = 12,000,000
d = wire DIA (inches)
n = number of free coils (use total coils - 1.5 if in doubt)
D = coil DIA (coil outside DIA - wire DIA)

Gotta separate a strut from it's coil before I can do the reality check, so I'll get those numbers as soon as I get some more free time.

HF

[tkinsel5]

without a doubt this is the best spring thread i've ever read! please anyone refer to my new post on the matter. thanks...

[HEMI-Fit]

I finally got around to putting my spare springs on an analog/mechanical scale to do a physical rate check. The fronts compare well to my calculated rates above, and the overall average is 108 lb/in. Tossing the lowest rate, the average goes up to 114.5 lb/in.

The rears don't compare so well - the overall average rate was 115.5 lb/in, and tossing the lowest gave 119.7 lb/in.

HF

[tkinsel5]

so ivan, are you still running your eibach pros? with or without stock dampers? if stock, how ya holding up?

wish i could have been at the meet! looked fantastic...

[ciburri]

Originally Posted by tkinsel5

so ivan, are you still running your eibach pros? with or without stock dampers? if stock, how ya holding up?

wish i could have been at the meet! looked fantastic...

Yep,
still on Eibach Pro's and OEM dampers. No ill effects to dampers so far.
It is a bit harsh up front since fronts are not progressive. I plan on going to some sticky 205's when I wear tires down by the fall. I do not mind fat tire look especially with black wheels. That will soften things up a bit and make it possible to fly over ever worsening California FWY's and local roads much better than now. Road construction zones are the worst! It is easier to climb sidewalks than "crash" over some "transitions" of work in progress.
At first my wife preferred OEM Civic softer suspension being 9 months pregnant, but now she prefers to ride in the Fit in the back. It is a lot easier to get in and out with taller roof line of the Fit!
Looks like Fit will be a weapon of choice when her water breaks! Red stroller and red car seat with a base are in it already as well as a hospital bag!

[ezekiel_771]

great info in this thread. much appreciated to have access to all the numbers, and opinions all in one place. I currently have an eibach pro kit on order and should be arriving tomorrow. One thing i have had questions on is the true benefit of the progress rear sway bar. every review i have read has been thumbs up, but since the suspension out back is torsion beam, would it be better to put on a font sway bar instead? and leave the back as is. after going though the thread it seems like i might want to add the rear bar to increase the rear stiffness, but just was curious on what other opinion were. if it helps for reference, my fit will be daily driven, as well as a weekend auto x toy.

Thanks much,
brad

[EXWRX]

I'd check the rules in AutoX. I think MrFrogge uses the front bar, because it doesn't move him up a class. I think for a pure street driven car the rear bar will be more enjoyable, but I haven't driven one with a front bar.

[ezekiel_771]

alright, thanks ill check into the different restrictions among classes. i guess the biggest thing i am afraid of is if i eventually put on a front and rear sway bar, the car will handle more like the factory setup with a neutral or understeer effect. since the rear swaybar is pretty tried and true, i suppose its a good starting place, and then decide from there.