custom spring rate question - H&R spring or Eibach ERS
 

seriously considering custom spring rate H&R 2.5" I.D. springs but i have no idea how long they need to be. i want to keep same ride height as my H&R sports, but for race spring i can choose 6, 8, 10, 12, 14" long springs from 150 to 900lbs

please keep in mind, this is for a street car that will occasionally see auto-x duties, but not often. it is for all suspension purposes a street car daily driven so 900lb springs are not going to help me.

H&R sports are supposedly- 330F/280R (P/P) so i'm thinking either

425F/400R
425F/375R
400F/375R

i just need to know the size (length) i'd need to order. these springs will be paired up with Koni Yellows.

i'm very seriously considering these....pretty much 100% gonna buy em, just need to know some info. i've emailed H&R as well for some input

ok I'll bite.. (since it looks like you've done a biut of research..)

1) do you have coilovers?

2) what shocks do you have?

(I suck don't answer the seco0nd question you have Koni yellows)

assuming you have coilovers.. I recommend Eibach ERS springs... H and R won't admit it but they just repaint Eibach stuff anyways...

so now rates.. I personally have 400f 450R and without my sway bar the car would handle like a stock car is expected to handle.

Anyways with that said .. 7 or 8 inch springs are perfectly ok to get with coilovers.... I wouldn't go shorter then 7 or longer then 8...

here is my summer set-up:

Koni Yellow shocks (just ordered them now)
GSR front upper strut brace
CTR 22mm rear sway with beaks kit
Hankook R-S2 Z212 tires in 205/50/15

and current springs are H&R sports but thats what i want to replace


after reading more, i'm thinking 400/375 ior 400/400 is the way to go. its daily driven so no more the 400 or my back will be killing my with these roads, but if stock is 330, 70F and 95R seems like a nice upgrade. not sure, but i believe 2.5 i.d. springs are linear, i know i've still got more research to do, doing it right now too.

thanks for the help.

read my last post... (I edited it)

I recommend you get coilovers (the sleeves get them from KONI for their shocks) if you don't then you can't use custom springs

why coil overs over just shock and spring, purely for ride height and use a smaller length spring? i won't be going any lower then 1.8F/1.6R as with this settings my camber is -2.25 anyways...which is fine, its a fun setting for corners :D

for rates i'm thinking 400F/375R or 400/400. don't want to stiff and don't want the ass to come out to much, the 22mm RSB already helps alot in that dept, even with stock winter suspension.

Coilovers because of Spring Design

if you look at your H and R Sports you will see that one end is flat and the other end the coiled wire just ends, it's not flat.

for regular cars this is ok and on our civics the spring perch requires this shape.

for custom springs with custom rates both ends of the spring have the wire tapered to create the flat surface. this results in needing a flat surface on the shock (since the spring perch isn't flat.) this requires you to get coilovers since the spring perch on a coilover is flat. custom rated sprinsg were only meant for coilovers really.

for handling keep it at 400/350 it'll be comfortable and keep the rear under control.

wicked, thanks for the help. i'll price the spring perch from Koni and compare the total price with just getting Ground-Control coil-overs. Seems Koni Yellows and GC are a match made in heaven from the way people talk about them in reviews.

One other question, the Racing 2.5" I.D. springs, they progressive or linear. The Sports were progressive according to the link.

400F/350R = increase of 21% stiffer Front and 25% stiffer Rear. dosen't seem like much stiffer if the sports really are 330/280.

425/375 = increase of 29% stiffer front and 34% stiffer rear

these are all based on 330F/280R being accurate for H&R sports.

custom springs are always linear.

you can't compare the spring rate of a progressive spring to a linear spring because a progressive one changes over it's range of compression (and it just royally sucks)

if you get a ground control kit get the springs with the kit or you'll end up wth the kit containing 200f and 180 rear and need to buy new springs... I know I have those springs sitting at home (I might make jumping shoes out of them.....)

anyways I have 400F and 450 rear and it's bearable... go with 400 front and 350 rear.. you'll like it .. also remember springs are cheap for a set of 2 so if you don't and need to go stiffer you can.

Also most ERS springs are in 50 pound increments in the 2.5 ID springs so the 425 and 375 are most likely 2.25 ID (you want 2.5 ID since you will find they are easier to sell and easier to trade with other people since more people have them it's a better size to have)

perfect, thanks for the help. listed my sports in the classifieds and i'm going with these in 400F/350R with the yellows. should be exactly what i'm after with the 22mm RSB

thanks again

you are welcome....