Subaru WRX Forums banner
1 - 20 of 23 Posts

·
Registered
Joined
·
1,252 Posts
Which STI LCA and which WRX? There is a little difference between 08-10 and 11+ in both WRX and STI.

The 11 WRX for the most part is a straight bolt on for 08-10 and 11 STI LCA, the widetrack WRX is the same dimensions as an STI.

To bolt an STI LCA to a 08-10 WRX, you need to make it widetrack. Technically you need 11+ WRX axles, sway bar, struts, hub carriers as well as the STI LCAs, to do it like Subaru did. Though you can probably get away with just the arms and axles if you run camber bolts up front to correct the alignment and some end links like Kartboys with spacers to run the narrow sway bar. Someone over on Legacygt.com (05-09 front same as 08-10 Impreza) claimed that you can just bolt the arms on but another tried it and had his axle pull out of the trans a little causing a leak.
 

·
Registered
Joined
·
173 Posts
I have sti arms on my 09 wrx... i havent changed anything else at all... i do have some more caster if that makes any sense to you, and therefore my aggressive wheel/tire setup rub the front fender liner a little bit.. Other than that i have had zero issues.
 

·
Registered
Joined
·
137 Posts
Discussion Starter · #4 ·
I have an 09 wrx. Bummer I thought they would bolt up and not change any angles or anything. I was hoping to save some weight but oh well. Are they even that much lighter?
 

·
Registered
Joined
·
1,252 Posts
Thanks for the info. So few out there have done this there is little info.

So no axles issues? What is your camber setting now? Did you have to do anything to correct it, i.e. camber bolts in the bottom strut bolt, or did the stock camber bolt give you enough adjustment? What did you do about the sway bar, just add spacers to the links or STI sway bar?

FYI the caster, yes we should expect more of that, the STI and 11+ WRX arms add caster over the 08-10 arms, in addition to the wider track.

Any info you can give is very helpful for those doing this in the future!

Dragonfueled they are not that much lighter, a few pounds. If you want straight bolt on and Aluminum, 06-09 Legacy Spec B arms are what you want.
 

·
Registered
Joined
·
173 Posts
I havent had any issues yet. They do make it a widetrack which gave me some negative camber.. I am also running bc coils and 18x9 +35 wheels with 245-40-18 tires so i needed neg camber to make it look/fit right anyways. And i havent done anything about the links.. they look fine to me... i didnt know STI's had wider sway bars than the wrx's
 

·
Registered
Joined
·
173 Posts
If more research can be done and proven that there arent any issues ( ive had mine on for 5k miles with no issues) and someone is interested in buying them, id be willing to do a trade plus cash... Im going back to stock soon anyways
 

·
Registered
Joined
·
1,252 Posts
The arms are 2-3 pounds lighter if that. Less unpsrung weight is great, the arm does pivot though, most of the mass is close to the pivot point so much of it is actually sprung mass. I had the Spec B arms on my WRX. Wouldn't have known much difference but the Group N bushings in them were the big deal. Subaru uses aluminum arms on the STI for a reason, but the benefit is subtle. A bigger benefit of the STI arms is the extra caster.

It is easier and generally cheaper to save a little weight with your wheels and tires.
 

·
Registered
Joined
·
98 Posts
bumping this back up.

ive been considering the 2011+ STi front LCAs. wanting the spherical joint and more negative camber (i normally max out the stock bolt, so i can dial it back if im adding more). ive also considered the spec B arms, but thought they were just AL equivalents of the stock WRX arms. are you saying they INCLUDE the Group N bushing? or did you add them in separately?

some quick pricing ive seen online shows the spec B arms at ~300/ea and the GrpN bushings at ~200/ea. did you really drop 1000 on new front control arms?
 

·
Premium Member
Joined
·
5,411 Posts
no, they do not include the group N bushings. they were installed separately.

yeah, i dont know too many folks that would buy new. both andrew and i imported the jdm arms (used) when they became available. i think he also imported his group n bushings as well and installed them then sold them to a buddy of mine and then we found them a new home with an LGT racer.
 

·
Registered
Joined
·
98 Posts
also another question, regarding the steering rack differences between the 08-10 WRX and the STi.

are any of the parts of the STi rack LONGER? to account for the wider track width.

if so what is longer?
the rack itself?
the inner tie rods?
the outer tie rods?

is there enough available threads to just thread out the out tie rod to make up the difference?
 

·
Registered
Joined
·
98 Posts

·
Registered
Joined
·
1,252 Posts
Keep in mind track width accounts for the hubs and the center of the tire patch, IIRC there is a slightly different offset to STI wheels 53 vs 55. So the real difference could be less or greater than 15mm.

The jury is sort of out on this one, there was a Legacy guy who did this and said his axles were leaking at the trans because they pulled out slightly. Another did this and said it worked fine. Opinion on NASIOC was that the 15 or so mm is too much not swap axles. The previous gen wagon to sedan swap was only a 5mm different so most were able to make that swap and run fine.

You may just have to try it out for yourself on this one.

I believe the steering rack width is in the tie rods the rack dimensions being the same. Also you would need the wider sway bar with STI arms but might be able to bridge the gap with some spacers on your end links.
 

·
Registered
Joined
·
98 Posts
Ok well if the track width of the STi accounts for wheel offset, and it was measured with the 53mm offset.

That gives me 2mm less per side. Putting us at 14.5mm difference per side from just the LCA/hub.

Do you know for sure if the inner or outer tie rods are the difference? I'm going to assume inner, based on the fact that the Whiteline RCA kit is the same part between WRX an STI. But maybe there is just enough threads? Or the WL kit is made to STi lengths and just threaded in more on the WRX application. There's just so many possibilities lol.

What I'm trying to come to is trying to figure a difference in axle length. I'd love to just "wing it" but really don't want to risk it popping out and getting fluid everywhere. But at the same time I don't want the added expense of new axles if I don't have to lol.

EDIT: according to opposed forces, the outers are the same PN and the inners are a different PN
 

·
Registered
Joined
·
98 Posts
so i broke down and just bought a set of 2011 WRX front axles (used).

when i get some extra cash, ill pick up the control arms. ill probably have to buy new though :( dont appear to be too many of these floating around on ebay or otherwise.
 
1 - 20 of 23 Posts
Top