Welcome to the North American Subaru Impreza Owners Club Friday September 17, 2021
Home Forums Images WikiNASIOC Products Store Modifications Upgrade Garage
Click here to visit TireRack
Brakes & Suspension Forum sponsored by The Tire Rack

Losing traction? Need new tires?
Click here to visit the NASIOC Upgrade Garage...
Go Back   NASIOC > NASIOC Technical > Brakes, Steering & Suspension

Welcome to NASIOC - The world's largest online community for Subaru enthusiasts!
Welcome to the NASIOC.com Subaru forum.

You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, free of charge, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, so please join our community today!

If you have any problems with the registration process or your account login, please contact us.







* As an Amazon Associate I earn from qualifying purchases. 
* Registered users of the site do not see these ads. 
Reply
 
Thread Tools Display Modes
Old 04-01-2014, 11:53 AM   #1
th283819
Scooby Newbie
 
Member#: 295063
Join Date: Sep 2011
Chapter/Region: NESIC
Location: Colchester, CT
Vehicle:
2011 Stg 2 WRX Hatch
DGM

Default 08+ STi Rear Sway Bar Size (Comparing stock '08/'09 to '10+)

I am trying to confirm my research on 08+ STi rear sway bar sizes.

From what I have gathered,
the '08 and '09 STi rear sway bar size is 18mm,
and the '10+ STi rear sway bar size is 19mm.

Can someone confirm this? I havn't found a clear source from someone who has measured both. I know the 19mm from the '10+ STi is a cheap upgrade for the WRX, and I have an opportunity to pick up the rear sway bar from a 2008 STi for basically nothing, but was trying to research my options and determine whether the cost difference was worth trying to find something from a '10+ vs. basically getting something free from a 2008 STi.

Also, I know the difference is minor but noticeable for the upgrade from the stock 16mm rear wrx sway bar to the stock 19mm rear STi sway bar. But would the 18mm be that much different from the 19mm?

Looking for some clarification and if anyone has any experience with the above upgrade. I know most will say just upgrade to aftermarket and go 24mm/22mm f/r, but I don't really have the funds for that at the moment. So if i could upgrade the rear for basically nothing, I might do it.

Thanks
* Registered users of the site do not see these ads.

Last edited by th283819; 04-01-2014 at 02:43 PM. Reason: Clarification of Title (don't want people to think I'm asking "which aftermarket size do I choose")
th283819 is offline   Reply With Quote
Sponsored Links
* Registered users of the site do not see these ads.
Old 04-01-2014, 04:12 PM   #2
isotopesope
Scooby Specialist
 
Member#: 265783
Join Date: Dec 2010
Chapter/Region: RMIC
Location: the fern behind the porn couch
Vehicle:
2017 Forester XT
Niner ROS 9

Default

you have the sizing and year differences correct.
http://www.subarugenuineparts.com/pr...oducts_id=1518
http://www.subarugenuineparts.com/pr...oducts_id=1690

i recently swapped my wife's 2012 impreza sport's 16mm rear sway bar with the 19mm STi one. while it made a nice improvement, i was quite underwhelmed.

if you're getting the 18mm one for free, why not, but it's not going to blow your socks off.
isotopesope is offline   Reply With Quote
Old 04-01-2014, 08:37 PM   #3
jaboyd
Scooby Specialist
 
Member#: 247304
Join Date: May 2010
Chapter/Region: South East
Location: Knoxville, TN
Vehicle:
2011 STI
WR Blue

Default

STI OEM bars

2008 - 2009, front 20mm, rear 18
2010 SE, front 20, rear 19
2011 -14, front 21, rear 19

STI Oem springs
2008-2009, front 217 #in, rear 194 #/in
2010 SE, front 251 #/in, rear 249 3/in
2011- 14, front 251 #/in, rear 297 #/in
jaboyd is offline   Reply With Quote
Old 04-01-2014, 09:08 PM   #4
th283819
Scooby Newbie
 
Member#: 295063
Join Date: Sep 2011
Chapter/Region: NESIC
Location: Colchester, CT
Vehicle:
2011 Stg 2 WRX Hatch
DGM

Default

Thank you both.

Yeah I can get the 18mm for free so I might as well spend the half an hour installing it and see what happens.

Again. Thank you for the confirmation of the info.
th283819 is offline   Reply With Quote
Old 04-02-2014, 11:29 PM   #5
Slasenger
Scooby Newbie
 
Member#: 382731
Join Date: Feb 2014
Location: Florida
Vehicle:
2012 WRX
Rally Blue

Default

If you really want a difference, get new 24 mm in front, 22 in back, and new end links. I take my wrx on the track and it made a world of difference around the corners.
Slasenger is offline   Reply With Quote
Old 04-03-2014, 05:58 AM   #6
th283819
Scooby Newbie
 
Member#: 295063
Join Date: Sep 2011
Chapter/Region: NESIC
Location: Colchester, CT
Vehicle:
2011 Stg 2 WRX Hatch
DGM

Default

Quote:
Originally Posted by Slasenger View Post
If you really want a difference, get new 24 mm in front, 22 in back, and new end links. I take my wrx on the track and it made a world of difference around the corners.
Thats the plan. I just don't have the money for it right now.
th283819 is offline   Reply With Quote
Old 04-03-2014, 12:22 PM   #7
isotopesope
Scooby Specialist
 
Member#: 265783
Join Date: Dec 2010
Chapter/Region: RMIC
Location: the fern behind the porn couch
Vehicle:
2017 Forester XT
Niner ROS 9

Default

Quote:
Originally Posted by jaboyd View Post
STI OEM bars

2008 - 2009, front 20mm, rear 18
2010 SE, front 20, rear 19
2011 -14, front 21, rear 19

STI Oem springs
2008-2009, front 217 #in, rear 194 #/in
2010 SE, front 251 #/in, rear 249 3/in
2011- 14, front 251 #/in, rear 297 #/in
thanks for this! didn't realize 2010 SE STi's have unique spring rates. do you know when the shorter rear springs started? was that in 2010 or 2011?
isotopesope is offline   Reply With Quote
Old 04-03-2014, 12:58 PM   #8
jaboyd
Scooby Specialist
 
Member#: 247304
Join Date: May 2010
Chapter/Region: South East
Location: Knoxville, TN
Vehicle:
2011 STI
WR Blue

Default

I believe the 2010 SE was the basis for tweaking and setting the stiffer rear 2011 spring rate and imm larger front bar. Not sure what "shorter" means...not aware of a height change.
jaboyd is offline   Reply With Quote
Old 04-03-2014, 01:23 PM   #9
isotopesope
Scooby Specialist
 
Member#: 265783
Join Date: Dec 2010
Chapter/Region: RMIC
Location: the fern behind the porn couch
Vehicle:
2017 Forester XT
Niner ROS 9

Default

Quote:
Originally Posted by jaboyd View Post
I believe the 2010 SE was the basis for tweaking and setting the stiffer rear 2011 spring rate and imm larger front bar. Not sure what "shorter" means...not aware of a height change.
i believe the ride height is the same, but the rear shocks have a shorter stroke and shorter springs, at least on the 2011+. i know the 08 STi has the same length spring as the WRX though... and *maybe* 09 too, since they share the same spring rate? i always thought 2010 was the same as 08/09... and wondered if they also had the longer spring.

phenryiv1 installed 08 STi rear and 2011 STi front springs and koni's on his widebody 2011 wrx:
http://forums.nasioc.com/forums/show....php?t=2322600

i have 2011 STi springs and Koni's on my 08 wrx. i didn't compare them to my wimpy 08 stock springs, but the rear STi springs are 30mm shorter than some 2012 WRX springs i also had laying around...



i machined some spacers to raise my spring perches about 8mm to accommodate the shorter spring, with very little pre-load. at first, my spacer was 30mm to make up the exact difference and add 3/4" preload (like on a stock WRX), but that made my rear end monster truck high... about 30mm too high.

Last edited by isotopesope; 04-03-2014 at 01:28 PM.
isotopesope is offline   Reply With Quote
Old 09-14-2021, 08:26 PM   #10
Speed Assault
Scooby Newbie
 
Member#: 289598
Join Date: Jul 2011
Location: S. Bay CA
Vehicle:
2008 impreza wrx

Default

Quote:
Originally Posted by Slasenger View Post
If you really want a difference, get new 24 mm in front, 22 in back, and new end links. I take my wrx on the track and it made a world of difference around the corners.
The important missing detail here is what Suspension dampening you all have?
You are forgetting that it Depends on your Struts or if using Coilovers also.

my 08 WRX is 20mm Front sway , 15mm Rear . so reading these threads that the rear sway is 18 is not accurate. My wrx bought from Subaru Dealer all stock)

I swapped in a 22mm rear not knowing at the time that its not good to have larger rear but obviously it was a world of difference. I cannot say for sure I I felt anything bad as I soon added a STI LSD rear diff, another HUGE improvement!

Now I have Coilovers they seem to handle the sway as well and I just swapped back the 15mm rear, but on a hard fast turn with dip in the road while turning the rear slid out a bit, but I believe the LSD and the coilovers helped the card more than the rear sway did.

Last edited by Speed Assault; 09-15-2021 at 01:02 AM.
Speed Assault is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

All times are GMT -4. The time now is 10:09 AM.


Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2021, Jelsoft Enterprises Ltd.
Powered by Searchlight © 2021 Axivo Inc.
Copyright ©1999 - 2019, North American Subaru Impreza Owners Club, Inc.

As an Amazon Associate I earn from qualifying purchases.