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Discussion Starter · #1 · (Edited)
Introduction

This is the Suspension and Handling Technical Reference Thread.

A Technical Reference is a document, link or thread containing factual information such as diagrams, specifications, procedures, etc.

This thread contains technical reference documents, links to threads useful as technical reference, as well as links to outside reference sources.

Please do not post comments here. Instead PM the author or post a new thread commenting on a particular post in this thread.

Please do feel free to post your own technical references, but please insure that they are authoritative - I want to try to avoid mis-information in this thread!

Thanks,

Chris
 

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Discussion Starter · #2 · (Edited)
Front Suspension Diagram

Service Manual Excerpt
 

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Discussion Starter · #3 ·
Rear Suspension Diagram

Service Manual Excerpt
 

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Discussion Starter · #4 · (Edited)
Brake Fluid Specifications Chart

Shamelessly stolen from:

http://www.swedishbricks.net/700900FAQ/Brake Fluid Comparison.htm

BP = Boiling Point. Wet is the important number - unless you change your fluid every day.

Temps are in deg. F.

When selecting a brake fluid, do some research on how long it lasts and how long YOU want it to last. For example, Motul 600 requires a 6 month or less change interval because it readily absorbs water. It'll give you WORSE performance when old than standard DOT 4 fluid. On the other hand ATE has a change interval of 2 YEARS because it does not absorb water as easily - this is what I use so I don't have to worry about it. AP Racing is not even listed because it has a change interval of "before every race". Probably a month or two on the street. A longer lasting fluid will give you better performance in the long run unless you follow these service intervals.
 

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OE suspension components

Stabilizer bar diameter (mm): front - 20, rear - 20(sedan)/17(wagon)
Jounce (mm): front - 80, rear - 110
Rebound (mm): front - 110, rear - 95
Spring rates (N/mm): front - 28.5, rear - 20.9/23.1 (Manual/automatic)

N/mm -> ft lbs/inch N X .2248/.03937 thus- front 162.7, rear 119.3

From SOA
 

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STi/SPT suspension FAQs

This is the same setup as the STi v7 RA uses. Here are some frequently asked questions:

2002 SUBARU IMPREZA WRX PERFORMANCE STRUT & SPRING FAQ


2002 Impreza WRX Struts
(These struts are sold separately, and are only available in the WRX STi Performance Suspension Kit)
What is the compression Rate? Front 2396 / 791 N, Rear 1668 / 690 N
What is the Rebound Rate? 0.3m/sec
What characteristics in under and over steering are affected by them? The vehicle characteristics remain neutral when the suspension kit is
What color are they? Red.
Are they rebuildable? No, they are not rebuildable.
Are they adjustable? No, they are not adjustable.
Who is the manufacture? The manufacturer is Kayaba (KYB).
What are the component sizes compared to stock?
Strut piston diameter 39.92mm (Sti version) vs. 22.00mm (Stock)

What process is done on them that make them better than the others? The specifications for performance were derived from WRC Subaru Rally Car experience
Will they work on other models? No, they are designed specifically for the WRX and must be used with the complete WRX performance suspension kit.
------------------------------------------------------------------------
2002 Impreza WRX Suspension Spring
(This part is not sold separately, it is only available in the Performance Suspension Kit)
What is the "Progressive Rate"? Front 38.0 N/m, Rear 33.4 N/m
What is the "Roll"? It will be less than the stock suspension system.
What are the I/D's and O/D's Inner diameter = 5.625", Outer diameter = 6.875"
What is the "Free-Length"? Rear (300mm), Front (270mm)
Will there be a height difference? Height remains the same.
Will the be a stiffening difference? Yes, there is a difference
If so, what % will the stiffness be? The system is stiffer than stock
Who manufactures them for Subaru? The front springs are manufactured by Mitsubishi-Seiko and the rear springs are manufactured by Nippon-Hatsujo.
What material are they made of? Steel.
What process is done on them that make them better than the others? The specifications for performance were derived from WRC Subaru Rally Car experience.
Will they work on other models? No, they are designed specifically for the WRX and must be used with the WRX performance suspension kit.
 

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Discussion Starter · #8 ·

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Discussion Starter · #9 · (Edited)

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Discussion Starter · #10 · (Edited)
Suspension Setup Table

The table at the following link talks about various suspension adjustments that can be made that effect the balance, feel, and/or total cornering traction of the vehicle.

Thanks bdoug for the reference.

http://www.clubsi.com/suspension_tweak_table.shtml
 

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Discussion Starter · #11 · (Edited)

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STi Group N suspension bushing part #s

FWIW I thought I'd list part #s for the Group N suspension bushings. First, the bushings are the same whether for GC, GD, GG.

front lateral link outer ST2022044020 also 20251AA040 (SOA part #-came from STi/SPT front sway kit-sedan)

front lateral link inner 20251AA050 (SOA part #-came from STi/SPT front sway kit-sedan)- don't have STi part # as I already had these

rear lateral link outer same as front outer

rear lateral link inner ST2022044040

trailing link front ST2022044000

trailing link rear ST2022044010

transverse link (front control arm) rear (left side) ST2020055010

transverse link (front control arm) rear (right side) ST2020055000


Big Sky
 

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Discussion Starter · #16 ·
Swaybar size chart

This PDF chart from Whiteline is used to figure the percentage stiffness change from one size of bar to another. It is valid for any solid steel bar and also useful for converting a quoted percentage stiffening for a hollow or aluminum bar into the equivalent steel bar for comparison to other products.

Thanks to Driggity for the link.

http://www.whiteline.com.au/docs/bulletins/010barup.pdf
 

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Discussion Starter · #17 · (Edited)

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Discussion Starter · #18 · (Edited)

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Labeled photo of the Group N bushings (not including strut tops, engine/tranny mounts/pitchrod):
 
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