Springs & Coil Overs facts and Spring Rate Chart

Springs


Stiffer, Stronger, Lower...Faster!

One of the first things enthusiasts do to increase the road manners of their ride is to install more aggressive springs.

Shorter, more aggressive springs achieve two goals: 1st - shorter springs decrease body roll and lower the cars center of gravity. The second benefit is that higher spring rates reduce suspension movement, with the hope of improving the wheel's contact patch with the road.

The downside is the eternal compromise: improved handling typically means a harsher ride. What is harsh to one person may not be harsh to the next. Though I used to think a "go-kart" suspension was the ultimate set-up, I find the older I get the less "harshness" I can take on my daily commute.
Progressive Springs

To help with the harshness issue, many spring manufacturers have "progressive" springs. What it really means is that the spring rate changes the more the spring is compressed. For example, a spring can be 10% softer than stock in its first inch of compression and then increase to 35% stiffer than stock as it is compressed farther. For daily driving, progressive springs will be more comfortable on the freeway and the provide the extra performace you want when cornering hard.

When installing new springs, be sure that the dampners (shocks) are correctly matched to the springs. Some spring manufactures design their springs to work with the factory dampers, while more aggressive spring rates require new dampers.

Also, when you lower the car, you automatically change the camber of your suspension (your wheels are tilted in). Though increased camber usually helps with grip at cornering limits, too much camber is a bad thing. Therefore, be sure to get an alignment after installing new springs.

Since the WRX is meant to be driven off road, be careful not to reduce the suspension travel too much (unless, you never plan to "rally"...but to me, that is what makes the WRX different than every other car on the road...it was MEANT to be driven off road...and boy is it a blast!)

Coil Overs

The Ultimate Suspension Upgrade Gives You Options

Coil Overs are a pre-engineered spring/dampener package that precisely matches the spring rate with the dampener (shock). The spring and the shock are arranged so the spring “coils over” the shock and act/move essentially as one piece.

The other advantage of coil overs is that the spring sits on an adjustable “perch”. This allows you to set the ride height…higher or lower…with in a specified limit.

Some manufacturers also give you the ability to control/set the rate of compression and rebound (up to 16 different settings for both compression and rebound).

By setting the rate of compression and rebound, and adjusting your ride height, you can fine tune your suspension to a specific track or your driving preference.

In other words, a good set of coil overs give you precise control of ride height and dampening rates.

*thanks to Scoobytuner for the artical

 

man you are working it, thanks for all the info!!

 

thanks. just tring to beef up the fact threads for teh mod squad area. its important for people to know how the mods they are buying affect their cars.

 

Good info!

 

With this chart the first number is the front spring rate in lb/in, the second number is the rear spring rate in lb/in, 3rd is front drop in inches, 4th is rear drop in inches.

Copied from this THREAD ON NASIOC


Spring Rate (lbs/in) Drop (in.)
Manufacturer Model Front Rear Front Rear Pillowball Dampening Notes
Subaru 2.5 RS GC stock 157 149
Subaru 2.5 RS GD stock 149 117
Subaru WRX sedan 5MT stock 163 119
Subaru WRX sedan 4EAT stock 163 129
Subaru WRX wagon 5MT stock 163 132
Subaru WRX wagon 4EAT stock 163 144
Subaru WRX STi USDM stock 224 195

Spring:
Eibach Pro '02-'03 Sedan 171 91-188 1.3 1.0 n/a n/a 7710.140
Eibach Pro '02-'03 Wagon 171 160 1.1 1.1 n/a n/a 7711.140
Eibach Pro '04 Sedan 1.3 1.0 n/a n/a
Eibach Pro '04 STi 234 229 1.1 0.6 n/a n/a
Espelir ASD GC 168 157 1.0 1.2 n/a n/a Linear
Espelir ASD '02-'03 185 145 0.8 0.8 n/a n/a Linear
Espelir ASD '04+ 252 145 1.4 0.8 n/a n/a Linear
Espelir GT '04+ 280 230 1.2 0.8 n/a n/a Linear
H&R Sport 1.5 1.4 n/a n/a Progressive
Hotchkis Street '02-'03 230 147 1.5 0.75 n/a n/a
Perrin 1.9 1.5 n/a n/a
Prodrive P1 (GC) 215 195 1.4 1.2 n/a n/a
Prodrive V7 (test data) 175 175 ~0.75 ~0.75 n/a n/a
RSR Down '02 216 177 1.8 1.2 n/a n/a Progressive
RSR Ti2000 '02 216 177 1.8 1.2 n/a n/a Progressive
RSR Ti2000 '04 268 195 1.6 1.4 n/a n/a Progressive
Subaru SPT WRX '02-'03 193 161 1.4 1.2
Subaru STi "pink" V6 196 174 1.2 1.2
Subaru STi "pink" V7 200 185 0.8 0.8
Subaru STi "pink" V8 257 217 0.8 0.8
Subaru STi "pink" WRX sedan 223 192 0.6 0.6
Subaru STi "pink" WRX wagon 223 192 0.6 0.6
Subaru STi V6 Tarmac 286 274
Subaru STi V7 Standard 188 173
Subaru STi V7 Type RA 217 190 0.4 0.4
Subaru WRX STi V8 Spec C 224 195
Subaru STi "Tuned by Arai" '04 324 274 0.6 0.6
Subaru STi Pink '04+ 257 217 0.8 0.8 n/a n/a "Linear"
Subaru STi Pink '02-'03 200 185 0.8 0.8 n/a n/a "Linear"
Tanabe NF210 GC 168 134 1.3 1.0
Tanabe NF210 '02-'03 140 112 1.5 1.0
Tanabe DF210 GC 196 140 1.5 1.0
Tanabe DF210 '02-'03 196 146 2.0 1.0
Tanabe GF210 GC 196 162 1.3 1.0
Tanabe GF210 '02-'03 168 157 1.5 1.0
Tanabe GF210 '04+ 240 224 1.3 1.0
Tein H Tech '02-'03 Sedan 196 140 1.1 0.6 n/a n/a
Tein H Tech '04+ Sedan 230 196 1.8 0.7 n/a n/a
Tein H Tech '04 STi 230 196 1.0 0.4 n/a n/a
Tein H Tech '05 STi 230 196 1.1 0.6 n/a n/a
Tein H Tech '02-'03 Wagon 196 140 1.1 0.6 n/a n/a
Tein H Tech '04+ Wagon 230 196 1.0 0.9 n/a n/a
Tein S Tech '02-'03 Wagon 218 157 1.7 0.8 n/a n/a
Tein S Tech '04+ Wagon 252 218 1.6 1.5 n/a n/a
Tein S Tech '02-'03 Sedan 218 157 2.0 0.7 n/a n/a
Tein S Tech '04+ Sedan 252 218 2.4 1.3 n/a n/a
Tein S Tech '04 STi 252 218 1.6 0.9 n/a n/a
Tein S Tech '05 STi 252 218 1.7 1.2 n/a n/a

 

Coilovers:
AST Powerstation 275 225
Bilstein PSS9 400 370 No 9 Progressive
Cusco Zero 1 '02+ 392 280 2.4 3.0 Yes 0
Cusco Zero 2-'02+ 392 280 2.4 3.0 Yes 5
Cusco Zero 2 R '02+ 392 280 2.0 2.8 Yes 5
DMS 50 Street Spec 224 180
DMS 50 Gravel Rally Spec (smooth) 224 180
DMS 50 Gravel Rally Spec (rough) 275 224
DMS 50 Tarmac Rally Spec 700 650
Ground Cntrl '02-'03 n/a n/a
Ground Cntrl '04+ n/a n/a
Ground Cntrl '04 STi 300 300 1.5 1.5 n/a n/a
HKS HiperDamper Yes 30
H&R 450 400 1.2-2.5 1-2 No No
JIC FLT A1 392 280 Yes Yes
JIC FLT A2 392 280 Yes Yes
Ohlins Road and Track WRX 230 171
Ohlins Road and Track STi 400 360
Tanabe Sustec Pro S OC 448 336
Tanabe Sustec Pro S OC II 448 336
Tanabe Sustec Pro SS 448 336
Tanabe Sustec Pro SS II 448 336
Tanabe Sustec Pro RR 672 560
Tein Basic '02-'03 Sedan 280 280 2.5 1.1 No No
Tein Basic '04+ Sedan 280 280 2.2 1.5 No No
Tein Basic '04 STi 280 280 1.6 0.7 No No
Tein Basic '05 STi 336 280 1.9 1.1 No No
Tein Basic '04+ Wagon 280 280 1.7 1.3 No No
Tein SS '02-'03 Sedan 280 280 2.5 1.1 No 16
Tein SS '04+ Sedan 280 280 2.2 1.5 No 16
Tein SS '04 STi 280 280 1.6 0.7 No 16
Tein SS '05 STi 336 280 1.9 1.1 No 16
Tein SS '02-'03 Wagon 280 280 1.7 1.3 No 16
Tein SS '04+ Wagon 280 280 1.7 1.3 No 16
Tein SS+ '02-'03 Sedan 280 280 2.6 1.3 Yes 16
Tein SS+ '04+ Sedan 280 280 2.4 1.7 Yes 16
Tein SS+ '04 STi 280 280 1.7 0.8 Yes 16
Tein SS+ '05 STi 336 280 1.9 1.1 Yes 16
Tein SS+ '02-'03 Wagon 280 280 2.0 1.1 Yes 16
Tein SS+ '04+ Wagon 280 280 1.8 1.5 Yes 16
Tein Flex '02-'03 Sedan 559 447 2.0 1.1 Yes 16
Tein Flex '04+ Sedan 559 447 2.4 1.7 Yes 16
Tein Flex '04 STi 559 448 1.7 0.8 Yes 16
Tein Flex '05 STi 559 448 1.8 1.1 Yes 16
Tein Flex '02-'03 Wagon 559 448 1.8 1.5 Yes 16
Tein Flex '04+ Wagon 559 447 2.0 1.1 Yes 16
Tein RA '02-'03 Sedan 447 335 2.3 0.8 Yes 16
Tein RA '04+ Sedan 447 335 2.3 0.8 Yes 16
Tein RA '04 STi 447 335 1.7 0.4 Yes 16
Tein RA '02-'03 Wagon 447 335 1.7 0.6 Yes 16
Tein RA '04+ Wagon 447 335 1.7 0.6 Yes 16
Whiteline Group4 280 224
Zeal B6 Street 448 336 Yes 6
Zeal B6 Race 560 448 Yes 6
Zeal V6 Street 448 336 Yes 6
Zeal V6 Race 560 448 Yes 6

 

wow crazy to see that gc/rs springs are that much stiffer than a gd/rs which is 1,000,000lbs heavier

 

Hmm. I wonder where the Saab 9-2x spring fit in there as far as lbs...??

 

Supposedly the shocks have slightly firmer damping and the spring rate is also slightly increased. Combined with the shorter ratio steering rack it makes for a sportier car apparently, although I've never driven one.

I'm closing this thread and using it for reference now, please continue your discussions in new threads.