Shocks and Spring Questions
01-12-2007, 10:08 AM
#1
Rennlist Member
Thread Starter
Shocks and Spring Questions
Is there some one or shop in the North East that re-valves Bilstein Coilovers?
Does the spring length have an affect on its function?
For example, would a 600# 2.5" i.d. x 8" long behave any different than a 600# 2.5" i.d. x 9" or 10" long. I suspect no to negligable when car is on the ground. Is that right?
I would like to go from 8" spring to longer length to minimize their "flopping around" when the wheel is off the ground.
TIA
Nader
Does the spring length have an affect on its function?
For example, would a 600# 2.5" i.d. x 8" long behave any different than a 600# 2.5" i.d. x 9" or 10" long. I suspect no to negligable when car is on the ground. Is that right?
I would like to go from 8" spring to longer length to minimize their "flopping around" when the wheel is off the ground.
TIA
Nader
01-12-2007, 11:56 AM
#2
Rennlist Member
Nader,
Bilstein North America/US will rebuild your shocks. You can find the service/rebuild dept. on their website. Around $100 per shock.
No, the characteristics of 600 lb/in springs should not vary, regardless of length. But you will still have the same "flopping" if you go to a longer spring, because you will need to lower the bottom spring perch by the same amount as the increase in spring length. E.g. if you replace your front 8" spring with a 9" spring, you will have to lower your perches by 1" to keep the car at the same ride height - so it will have the same amount of play when on jack stands.
I just did the opposite, I went from 9" front springs to 8" springs, and raised my perches by 1". But I have the same amount of free play when the strut/springs are unloaded.
There are kits you can get that put a small/thin tender spring (with a very low spring rate) in conjuction with the main spring - solely for the purpose of keeping the main spring in position with the car in the air. Eibach and Hypercoil make these kits for their spring sets, and I know that Paragon Products sells a setup.
Also, if you are concerned about weight, keep in mind that the 9" springs do weigh more than the 8" springs, possibly by as much as 1-2lbs each, depending on how they are wound (# of coils and wire diameter).
The rear shocks are limited by spring length. If the springs are too long, the bottom perch will hit the trailing arm, and if the springs are too short, you run out of threads on the shock body. I have 8" 400 lb springs that just fit, 7" 425 lb springs that are too short, and 8" 450 lb springs that are too long (because of the higher spring rate, the spring compresses slightly less than the 400s, so the perch is lower, just enough to hit the trailing arm). This problem is a combination of torsion bar indexing (I am using t-bars with the helper coil setup), ride height, spring rate, spring length, and lower spring perch & jam nut dimensions - so you may or may not run into the same problems/solutions as I have.
Bilstein North America/US will rebuild your shocks. You can find the service/rebuild dept. on their website. Around $100 per shock.
No, the characteristics of 600 lb/in springs should not vary, regardless of length. But you will still have the same "flopping" if you go to a longer spring, because you will need to lower the bottom spring perch by the same amount as the increase in spring length. E.g. if you replace your front 8" spring with a 9" spring, you will have to lower your perches by 1" to keep the car at the same ride height - so it will have the same amount of play when on jack stands.
I just did the opposite, I went from 9" front springs to 8" springs, and raised my perches by 1". But I have the same amount of free play when the strut/springs are unloaded.
There are kits you can get that put a small/thin tender spring (with a very low spring rate) in conjuction with the main spring - solely for the purpose of keeping the main spring in position with the car in the air. Eibach and Hypercoil make these kits for their spring sets, and I know that Paragon Products sells a setup.
Also, if you are concerned about weight, keep in mind that the 9" springs do weigh more than the 8" springs, possibly by as much as 1-2lbs each, depending on how they are wound (# of coils and wire diameter).
The rear shocks are limited by spring length. If the springs are too long, the bottom perch will hit the trailing arm, and if the springs are too short, you run out of threads on the shock body. I have 8" 400 lb springs that just fit, 7" 425 lb springs that are too short, and 8" 450 lb springs that are too long (because of the higher spring rate, the spring compresses slightly less than the 400s, so the perch is lower, just enough to hit the trailing arm). This problem is a combination of torsion bar indexing (I am using t-bars with the helper coil setup), ride height, spring rate, spring length, and lower spring perch & jam nut dimensions - so you may or may not run into the same problems/solutions as I have.
01-12-2007, 12:27 PM
#3
Rennlist Member
Join Date: Aug 2003
Location: Naperville, IL
Posts: 387
Likes: 0
Received 0 Likes
on
0 Posts
For the most part, anyone that "revalves Bilsteins" will be sending them to Cali. to have Bilstein do it. They'll all charge $100 + markup + proprietary valving (if appropriate).
