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Discussion Starter #1 (Edited)
All Info is Verified by Links Unless Otherwise Noted

Calculations Done Using Spring Rates Given by TIC for Factory 2008 STi

Contents

A. Factory 2008 STi Spring Facts

B. After Market Springs
1. Agency Power Performance Springs
2. Cobb Tuning Sport Springs
3. Eibach Pro-Kit Springs
4. Espelir Active Down Springs
5. H&R Sport Springs
6. RaceComp Engineering Functional Lowering Springs
7. RaceComp Engineering Sport Lowering Springs
8. RSR Ti2000 Down Springs
9. Subaru JDM Pink STi Springs
10. Swift Sport Springs
11. Tanabe DF210 Springs
12. Tein S-Tech Springs

C. Springs Listed from Most Lowered to Least Lowered

D. Springs Listed from Highest to Lowest Spring Rates

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A. Factory 2008 STi Spring Facts

Link: Info Provided by TurnInConcepts after given facts by SoA
Front Spring Rate: 217lb/in
Rear Spring Rate: 194lb/in


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B. After Market Spring Facts

1. Agency Power Performance Racing Springs

Link: Agency Power Performance Racing Springs Subaru WRX STI 08+

Front Drop: 1 1/4” (32mm)
Front Spring Rate & Increase: No Info Found
Rear Drop: 3/4” (19mm)
Rear Spring Rate &Increase: No Info Found
Skid Pad: No Info Found
Cost: $250 @ Agency-Power.com

2. Cobb Tuning Sport Springs

Link: CobbTuning.com - 08 STI Sport Springs

Front Drop: 7/8” (22mm)
Front Spring Rate & Increase: Estimated Rate of 240 lb/in based on Cobb's 10% Claimed Rate Increase
Rear Drop: 7/8” (22mm)
Rear Spring Rate & Increase: Estimated Rate of 232 lb/in based on Cobb's 20% Claimed Rate Increase
Skid Pad: from 0.94 g stock to 1.02 g
Cost: $250 at RallySportDirect.com

3. Eibach Pro-Kit Springs

Link: Eibach Springs - Performance Suspension, Lowering Springs, Shocks, Sway Bars, Coil-Overs and Wheel Spacers!

Front Drop: 1” (25mm)
Front Spring Rate & Increase: No Info Found
Rear Drop: 1” (25mm)
Rear Spring Rate &Increase: No Info Found
Skid Pad: No Info Found
Cost: $270 at Vivid Racing

4. Espelir Active Down Springs

Link: None Found and Info UNVERIFIED

Front Drop: 1 1/5" (30mm)
Front Spring Rate & Increase: 241 lb/in & Estimated 11% Rate Increase
Rear Drop: 1" (25mm)
Rear Spring Rate & Increase: 162 lb/in & Estimated 16% Rate Decrease???
Skid Pad: No Info Found
Cost: No Info Found

5. H&R Sport Springs

Link: Subaru WRX & STi Coilovers, Lowering Springs & Suspension - H&R Sport Springs 2008+ Subaru Impreza WRX / STi Free Shipping

Front Drop: 1" (25mm)
Front Spring Rate & Increase: No Info Found
Rear Drop: 1" (25mm)
Rear Spring Rate & Increase: No Info Found
Skid Pad: No Info Found
Cost: $270 @ HopUpRacing.com

6. RaceComp Engineering Functional Lowering Springs *Still in Development*

Link: http://www.iwsti.com/forums/1867071-post25.html

Front Drop: 1/5”- 2/5" (5-10mm)
Front Spring Rate & Increase: No Info Found
Rear Drop: 1/5”- 2/5" (5-10mm)
Rear Spring Rate & Increase: No Info Found
Skid Pad: No Info Found
Cost: No Info Found

7. RaceComp Engineering Sport Lowering Springs *Still in Development*

Link: http://www.iwsti.com/forums/1867071-post25.html

Front Drop: 4/5” (20mm)
Front Spring Rate & Increase: No Info Found
Rear Drop: 4/5” (20mm)
Rear Spring Rate & Increase: No Info Found
Skid Pad: No Info Found
Cost: No Info Found

8. RSR Ti2000 Down Springs

Link: None Found and Info UNVERIFIED

Front Drop: 1” (25mm)
Front Spring Rate & Increase: 263 lb/in & Estimated 21% Increased Rate
Rear Drop: 3/5” (15mm)
Rear Spring Rate & Increase: 208 lb/in & Estimated 7% Increased Rate
Skid Pad: No Info Found
Cost: No Info Found

9. Subaru JDM Pink STi Springs

Link: japanparts.com : PARTS DATABASE

Front Drop: 3/5” (15mm)
Front Spring Rate & Increase: 285lb/in & Estimated 31% Increased Rate
Rear Drop: 3/5” (15mm)
Rear Spring Rate & Increase: 228lb/in & Estimated 18% Increased Rate
Skid Pad: No Info Found
Cost: $480 @ JapanParts.com

10. Swift Sport Springs

Link 1: Mann Engineering - Subaru Parts and Performance
Link 2: NASIOC - View Single Post - Coming Soon! Swift Sport Springs for 2008 STI

Front Drop: 1” (25mm)
Front Spring Rate & Increase: 143-251 lb/in & 10-15%
Rear Drop: 1” (25mm)
Rear Spring Rate &Increase: 118-235 lb/in & 10-15%
Skid Pad: No Info Found
Cost: $310 @ MannEngineering.com

11. Tanabe DF210 Springs

Link: RallySportDirect.com - Tanabe DF210 2008 Sti Springs

Front Drop: 1.1” (28mm)
Front Spring Rate & Increase: 246lb/in & No % Info Found
Rear Drop: 1.1” (28mm)
Rear Spring Rate &Increase: 174lb/in & No % Info Found
Skid Pad: No Info Found
Cost: $275 at RallySportDirect.com

12. Tein S-Tech Springs

Link: S.TECH

Front Drop: 1” (25mm)
Front Spring Rate & Increase: 252 lb/in & No % Info Found
Rear Drop: 8/10” (20mm)
Rear Spring Rate Increase: 219 lb/in & No % Info Found
Skid Pad: No Info Found
Cost: $250 at RallySportDirect.com

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C. Springs Listed from Most Lowered to Least Lowered

1. New Agency Power Performance Springs (32/19mm)
2. Espelir Active Down Springs (30/25mm)
3. Tanabe DF210 Springs (28/28mm)
4. H&R Sport Springs (25/25mm)
5. Eibach Pro-Kit Springs (25/25mm)
6. Swift Sport Springs (25/25mm)
7. Tein S-Tech Springs (25/20mm)
8. RSR Ti2000 Down Springs (25/15mm)
9. Cobb Tuning Sport Springs (22/22mm)
10. RaceComp Engineering Sport Lower Springs (20/20mm)
11. Subaru JDM Pink STi Springs (15/15mm)
12. RaceComp Engineering Functional Lowering Springs (5-10/5-10mm)

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D. Springs Listed from Highest to Lowest Spring Rates

Insufficient data at this time.

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I will do my best to update this thread with new information and springs when it becomes available or is brought to my attention :D

-Steven
 

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Nice write up. Also, I believe Eibach has both a pro-kit and a sport line, which lowers the car even more. Not saying a good way to go, just another option out there.
 

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good info..once the spring rate info starts filling in, it will be very comprehensive

interesting about the spring rates that you have already provided. with the talk from those in the know about the rear spring rates being able to be higher (due to the motion ratio), it's funny that every company is making the rear rates lower like a traditional mcpherson strut on all corners vehicle
 

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Another piece of info you might want to include is whether they are linear or progressive rate. I had been planning to purchase the Cobb springs until I found out from Cobb via an email to their tech support that they are progressive, not linear rate. That's fine for looks, bad for any track duty.

Just a thought as I know many people have different uses in mind for their cars if they were to upgrade the springs
 

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Just add two more brand.

RSR Ti2000
Front Drop: 25mm
Front Spring Rate: 4.69 (kg/mm)
Rear Drop: 15mm
Rear Spring Rate: 3.72 (kg/mm)
Cost: $25844 yan




ESPELIR
Front Drop: 30mm
Front Spring Rate: 4.3 (kg/mm)
Rear Drop: 25mm
Rear Spring Rate: 2.9 (kg/mm)
Cost: $17955 yan

 

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I think the cost of the JDM pinks is off, they are ~115 each at japanparts, HM had them for 109 each, so the total is going to be ~$450. I really wish they were $240:lol:
 

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Discussion Starter #9
I think the cost of the JDM pinks is off, they are ~115 each at japanparts, HM had them for 109 each, so the total is going to be ~$450. I really wish they were $240:lol:
I didn't notice they were selling them spring by spring. How retarded :rolleyes:

Thanks for the heads up though.
 

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Discussion Starter #10
Just add two more brand.

RSR Ti2000
Front Drop: 25mm
Front Spring Rate: 4.69 (kg/mm)
Rear Drop: 15mm
Rear Spring Rate: 3.72 (kg/mm)
Cost: $25844 yan




ESPELIR
Front Drop: 30mm
Front Spring Rate: 4.3 (kg/mm)
Rear Drop: 25mm
Rear Spring Rate: 2.9 (kg/mm)
Cost: $17955 yan


Do you have the links to the info so I can add them?
 

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Very good info here, subscribed :tup:
 

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Discussion Starter #12
UPDATED
+ Factory STi Spring Rates from TIC
+ Espelir Down Springs, H&R Sport Springs, and RSR Ti2000 Down Springs.

Info verification pending links for Espelir and RSR Springs as noted above in Red.
 

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Discussion Starter #13
Nice write up. Also, I believe Eibach has both a pro-kit and a sport line, which lowers the car even more. Not saying a good way to go, just another option out there.
Per Eibach's Site, it says that both kits (Pro and Pro-Plus) have a 1" F/R (25mm) drop and no information about Spring Rates is provided. Find me a link if you can, so I can edit the Original Post :)
 

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Discussion Starter #14
Another piece of info you might want to include is whether they are linear or progressive rate. I had been planning to purchase the Cobb springs until I found out from Cobb via an email to their tech support that they are progressive, not linear rate. That's fine for looks, bad for any track duty.

Just a thought as I know many people have different uses in mind for their cars if they were to upgrade the springs
How can I find out which are Progressive and which are Linear?
 

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How can I find out which are Progressive and which are Linear?
You usually have to ask the manufacturer. That's how I found out on the Cobb Sport Springs and also on some H&R springs I was considering when I had the MS6.

You can alternately look at the spring's windings, if they appear to be equal length apart, they are most likely linear, if they are not equally spaced and are grouped tighter towards one end or the other, they are probably progressive. For example, I'm betting the RSR Ti2000's springs pictured further up in this thread are progressive just from the spring windings in the pic.

Still best to check with the manufacturer to be sure.

Hope this helps!
 

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This thread is missing the other Tanabe offerings (NF210, GF210)

Subaru WRX & STi Coilovers, Lowering Springs & Suspension - Tanabe NF210 Lowering Springs Subaru Impreza WRX STI (GRB) 08-08 Free Shipping!!!
tanabe 2008 wrx sti springs, 2008 wrx tanabe gf springs, sti 2008 lowering springs

The GF should lower the least.

Tanabe GF210 Lowering Springs Subaru Impreza WRX STI (GRB) 08-08

The GF210 coil spring is geared towards maximum performance, without compromising daily driveability. A subtle drop provides an aggressive stance, while the higher spring rates (+20% - 30% over stock) provide excellent handling and vehicle stability characteristics. These springs provide a very noticeable gain in performance when installed.

The GF210 is well mated with a performance shock upgrade to extract the full potential of the coil spring, but will also work with factory equipment.

Each coil spring application is tested for fitment and optimal weight distribution for sportier handling.
 

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After years ( almost two decades ) of modding cars from 510 datsuns, mini's, and subarus I have gone with H&R springs. I have yet to run coilovers on an STI, but as far a springs go the H&R's are the best. I plan on going straight to coilovers on my 08 so I can run edfc, but if I did run springs I would go with these.
 
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