mr. sparco

iTrader: (13)

Need some knowledge regarding fronts.

I ordered both 400 lb/in (8") and 350 lb/in (7") Eibach ERS springs for the fronts of my coilover setup. Not sure which to run.

Is 350 lb/in too soft for daily driving? Or would the 400 lb/in springs be more fitting? I've read (after the vendor shipped the springs) on other old school car forums that coilover springs are 90% of what a regular lowering spring rate would be. So .9x350 sets it at 315 which seems soft as the stock spring rate = 314.

I used to be on Tokico DSpec II adjustable shock/spring combo at 375f/r setup. It felt pretty good but I needed height adjustability so switching to a custom c/o suspension.

terrasmak

iTrader: (8)

Spring rate is spring rate, no idea what you you are talking about with the 90% thing. They could be talking about wheel rate, and that is something a bit different

guitman32

iTrader: (15)

I would run the 400.

Not sure what the distinction is between "coilover springs" vs "regular lowering spring," but as long as all you are doing is adding a threaded perch and swapping linear springs of the rate/length of your choosing (not altering geometry), the motion ratio and angle correction factor will not change, and therefore the proportion of spring rate to wheel rate will remain unchanged.

mr. sparco

iTrader: (13)

I think that's what it was wheel rate is different on coilovers. I'll have to go back and look more carefully.

Thanks for sharing the know.

terrasmak

iTrader: (8)

Spring rate is the same no matter what, if a spring is 500lb it is 500lb. What wheel rate is, wheel rate is what the wheel actually see's do to motion ratio.

I quick example of differences in wheel rate are the true coilover deal for the rear of our car. A 5k rear spring run on the shock body is equal to a 12k run in the spring bucket.

Motion ratios are different in different applications, some cars are 10% ish , others are 50% all depending on where the spring is connected to contro arm.

nizmo_0385

iTrader: (5)

Thanks for the info definitely learning here

mr. sparco

iTrader: (13)

Installed the 350#F and 375#R and adjusted the shocks. Rides super smooth even on 19s.

hazermang

I think my KW's stiffen all the way up to 500+ when you put them to work

ZROCM

iTrader: (6)

Wow, interesting. So 12K in the spring bucket is 670 lbs and the stock rear spring on a 2004.5 plus I think is 427 lbs. What a difference! I assume the ride would be extremely harsh. on the other hand when you match up the spring to a specific shock and/or shock setting that has adjustments, then it may be OK?

terrasmak

iTrader: (8)

Shocks do wonderful things, I think my bushings do more for harshness than the springs. Right now I'm at 16k front and 6k rear (rear on the shock)

ZROCM

iTrader: (6)

Interesting, I'm trying a 13K spring in the front and 5K spring in the rear (on the shock) using Stance Coilovers. The 13K spring is a swift spring and the 5K spring is from Stance. I have the damping on the front shock set to 4 down from full stiff and the rear down to 8 or 9 down from full stiff. I'm trying to obtain a comfortable ride around the city. I need to experiment more with the damping settings. But my first impression is I may have to go down to 12K spring in the front. I'm lowered about 1 inch. I tied a 10K spring in the front and found them to be too soft. I see some people like Stance and others do not. Well, I bought them, so I'm trying to see if they can work for me with certain spring rates.

terrasmak

iTrader: (8)

How much travel are you running ? I have about 1.5 inches of up travel in the front before the bump stop engages. It's a soft stock that bumps up the rate another 100 pounds when egaged and will compress another 1/2 or more. I have a little over 2.5 inches of travel till my tire could hit the fender liner. Setting travels probably helps a lot. I have seen my far share of improperly adjust coilovers, set the preload to 0 or just a hair and use body length to adjust height. I set travel with body length and height with preload, works so much better.

ZROCM

iTrader: (6)

I need to measure the up travel. I did install them setting the springs to 0 preload and then set the height adjusting the shock body up or down into the bottom support.

terrasmak

iTrader: (8)

Good chance you have little to no travel, that would cause a harsh ride.