Popular Spring and Coilover Tech Specs

[Thajones]

Borrowed from the gurus at b15sentra.net

Stock and Aftermarket Springs

If you are interested in dropping your car with lowering springs, at least know what your stock rates are, and those of the aftermarket product you are looking to get. Spring rates measure how "stiff" the springs are, measured in lbs/inch. Drop is how much lower your car will be compared to stock ride height.

The chart below was posted by chickracer over 2 years ago and shows the stock b15 spring rates. To the best of my knowledge, the 1.8s still uses the same rates as the GXE, and I don't think the SE-R or SpecV rates have changed for '04 or '05.


154F/247R - SpecV (all years)
134F/212R - SE-R (5spd/auto) and SE (w/PP)
134F/190R - 2.5S/LE/SE (w/o PP)
123F/190R - 1.8S/GXE/XE


Here are the spring rates and (drop) of the most popular aftermarket lowering springs. Understand that you really don't want to drop too much, and the rates should be higher than stock to compensate for less wheel travel:


180F/300R (1.2"F/1.0"R) Eibach Pro-Kit (gen2 #6362.140)
200F/333R (1.6"F/1.6"R) Eibach Sportline (gen2 #EIB4.6263)

168F/258R (1.3"F/1.1"R) Tanabe NF210
174F/258R (1.8"F/1.8"R) Tanabe DF210
207F/314R (1.3"F/1.1"R) Tanabe GF210

170F/270R (1.3"F/1.1"R) Tein S-Tech
154F/246R (0.9"F/0.6"R) Tein H-Tech

190F/280R (1.2"F/1.0"R) Swift Sport

230F/290R (1.5"F/1.5"R) Goldline

190F/240R (1.7"F/1.5"R) Progress a.k.a Intrax

172F/274R (1.6"F/1.6"R) Vogtland

280F/230R (2.0"F/2.0"R) Megan Racing

150F/190R (2.0"F/2.0"R) Sprint

???F/???R (1.5"F/1.5"R) B&G

???F/???R (1.5"F/1.4"R) H&R


I would stay away from Sprint because the drop is too low and rates too soft. Also, you really should know the rates of the lowering spring you are putting on your car, not knowing the spring rate is like not knowing the width of a tire. You need to know the rates to setup the suspension properly!

Also, here are the numbers for the Ground Control coilover sleeves, don't bother using these on stock dampers, the rates are too high. Use with Koni Sport for best results.

375F/300R (~1.0"-2.5"F/~0.5"-2.5"R) Ground Control (interchangable front and back)



Complete Coilover Systems


Nismo S-tune Kit
Spring Rates: 185F/300R (progressive, meaning this is just the MAX rate)
Swappable Springs: NO
Ride Height Adjust: NO (fixed at 1.0"F/0.6"R)
Damper Type: Twin Tube Hydraulic
Damper Adjustment: NO
Upper Mounts Incl?: YES
Install Difficulty: LOW (pops right into car)
Street Price: $800

Tein Basic
Spring Rates: 336F/336R (linear)
Swappable Springs: YES (+/- 56 ft/lbs)
Ride Height Adjust: YES (1.0"-2.4"F/0.5"-2.3"R)
Damper Type: Twin Tube Hydraulic
Damper Adjustment: NO
Upper Mounts Incl?: NO
Install Difficulty: MEDIUM (reuse stock upper mounts)
Street Price: $800

Koni/Ground Control
Spring Rates: 375F/300R (linear)
Swappable Springs: YES (+/- 25 ft/lbs)
Ride Height Adjust: YES (~1.0"-2.5"F/~0.5"-2.5"R)
Damper Type: Twin Tube Hydraulic
Damper Adjustment: YES (no notches, ~2 full turns from soft to stiff)
Upper Mounts Incl?: NO
Install Difficulty: VERY HIGH (reuse stock upper mounts, front strut housing, properly install GC)
Street Price: $850

Tein SS
Spring Rates: 336F/280R (linear, some use 392R)
Swappable Springs: YES (+/- 56 ft/lbs)
Ride Height Adjust: YES (1.0"-2.4"F/0.8"-2.3"R)
Damper Type: Twin Tube Hydraulic
Damper Adjustment: YES (16 way, 32 with EDFC)
Upper Mounts Incl?: NO
Install Difficulty: MEDIUM (reuse stock upper mounts)
Street Price: $1100

KSport
Spring Rates: 392F/280R (linear)
Swappable Springs: YES (+/- 56 ft/lbs)
Ride Height Adjust: YES (~1.0"-2.5"F/~0.5"-2.5"R) (can adjust overall damper length)
Damper Type: Twin Tube Hydraulic
Damper Adjustment: YES (36 way)
Upper Mounts Incl?: YES
Install Difficulty: LOW
Street Price: $850

JIC FLT-A1
Spring Rates: 392F/280R (linear, several use 336R)
Swappable Springs: YES (+/- 56 ft/lbs)
Ride Height Adjust: YES (~1.0"-2.5"F/~0.5"-2.5"R) (can adjust overall damper length)
Damper Type: Twin Tube Nitrogen Gas
Damper Adjustment: YES (5 way)
Upper Mounts Incl?: YES (pillowball w/front camber adjustment)
Install Difficulty: LOW
Street Price: $1150

JIC FLT-A2
Spring Rates: 392F/280R (linear, several use 336R)
Swappable Springs: YES (+/- 56 ft/lbs)
Ride Height Adjust: YES (~1.0"-2.5"F/~0.5"-2.5"R) (can adjust overall damper length)
Damper Type: Mono Tube Nitrogen Gas
Damper Adjustment: YES (15 way)
Upper Mounts Incl?: YES (pillowball w/front camber adjustment)
Install Difficulty: LOW
Street Price: $1750