[STizer]

Hi everybody,

This is my first thread on IWSTI, and so far I have found the info on the forums quite rewarding (awesome resources). I live in Australia and own a black 07' STi, I've just recently joined IWSTI.

I just wanted to ask if anybody has moved the strut assembly on their STi forwards and angled back? This will increase the wheelbase on the vehicle and provide for much better castor (a couple degrees extra).

Of course, this set up consists of all necessary aftermarket suspension components. It cannot be done with your normal suspension components. You would still have to implement the coil-overs, anti-lift kit etc.

The Litchfield Type-25 has the same suspension modification that I have mentioned above. Originally, Litchfield derived the idea from the Jap-spec Spec C. Very radical, but can it be done? Has it been done to other STi's?

I will soon enquire about the idea with the professionals, but I am after possible feedback at this stage.

Thanks people!

[stretch]

IIRC, the 2005-2006 STI's already have the Spec-C geometry. I'm not actually sure what part changed to get the additional castor, though. Nonetheless, you can kind of take things into your own hands by installing a Whiteline or GT-Spec anti-lift kit and doing the "free castor mod", found here: free castor mod?.

[STizer]

Cheers for the feedback, much appreciated!

The Whiteline anti-lift kit is a must have for the mod, and new coil-overs are necessary with the correct valving to make it work properly. The 07' STi does share the base suspension geometry of the Spec-C, except that the Spec-C had the ability to run more castor. I am pretty sure the 07' STi runs 3.5 degress of castor, this was increased to 5 degrees on the Spec C/Type-25. But more importantly I believe the entire strut assembly was moved forward to increase the wheelbase and to help with max castor. Along with the quick steering (2.2 turns to lock) gear ratio and extra weld spots on the front strut tower mountings, its the perfect STi street setup to take some of that mid-turn understeer away.

I will inquire with Whiteline suspension in Sydney and let you guys know how it all went.

I feel it can be done, but I had look at the suspension the other day, I believe we have to move the entire strut assembly forward which means angling the coil-overs as well somehow i.e. maybe with some special brackets.

[twiSTies]

Originally Posted by stretch

IIRC, the 2005-2006 STI's already have the Spec-C geometry. I'm not actually sure what part changed to get the additional castor, though. Nonetheless, you can kind of take things into your own hands by installing a Whiteline or GT-Spec anti-lift kit and doing the "free castor mod", found here: free castor mod?.

The part change between the 2005/06 vs. 2007 STi was the front control arms themselves. 2005/06 used the Spec-C aluminum front control arms that came with more caster. This effectively increased the wheelbase and moved the struts forward more like the OP is stating. This was the only front suspension change on the 07 vs. the 2005/06, IIRC.

[sti2relaxxin]

Originally Posted by twiSTies

The part change between the 2005/06 vs. 2007 STi was the front control arms themselves. 2005/06 used the Spec-C aluminum front control arms that came with more caster. This effectively increased the wheelbase and moved the struts forward more like the OP is stating. This was the only front suspension change on the 07 vs. the 2005/06, IIRC.

The '07's front control arms are aluminum as well, but they definitely decreased castor.

[Treadwell]

I'm also curious as to what alignment specs were used on the Type 25.

[Turninconcepts.com]

The Type 25 suspension is no secret. They use AST dampers with off the shelf springs, whiteline 24mm or 22mm sway bars and a whiteline ALK. That's really it. We actually started our coilover research with damping used in the AST Type 25 spec coilovers and did not like it. We also didn't like the crazy wacko springs they used. After much research we ended up with what we sell today which we feel is far superior.

As far as the caster goes, this is quite easily increased as mentioned. Install the ALK or equivalent and do the free caster mod with maybe some caster adjustable top hats and you're done. This will net in the 6* range of caster and essentually push the wheel farther forward in the wheel well.

The 07 sti uses the non spec C JDM aluminum control arms which do not add nearly the caster of the spec c arms. You can still do the free caster mod on them though for .5* or so more.

Tony

[WolfPlayer]

FWIW, I asked Whiteline this question a long time ago. Here is the response they sent back ...

Hi Tim,

P25 has 1K4042R coil overs in her and KCA 251M strut tops; Front bar is BSF36Z and the rear BSR37Z. If you jump onto the online catalogue the rest of the parts can be found in their i.e. roll centre kits anti lift, bushes, etc. We don’t sell the coilovers anymore but their may be a possibility we still might be able to get a set for you.

http://www.whiteline.com.au/

Cheers,

David Chenery
R & D / Technical
REDRANGERpty ltd
The home of NOLATHANE andWHITELINE
1300 88 2355
Fax 02 4340 2466
dave@redranger.com.au

[OA4S]

Originally Posted by Turninconcepts.com

The Type 25 suspension is no secret. They use AST dampers with off the shelf springs, whiteline 24mm or 22mm sway bars and a whiteline ALK. That's really it. We actually started our coilover research with damping used in the AST Type 25 spec coilovers and did not like it. We also didn't like the crazy wacko springs they used. After much research we ended up with what we sell today which we feel is far superior.

As far as the caster goes, this is quite easily increased as mentioned. Install the ALK or equivalent and do the free caster mod with maybe some caster adjustable top hats and you're done. This will net in the 6* range of caster and essentually push the wheel farther forward in the wheel well.

The 07 sti uses the non spec C JDM aluminum control arms which do not add nearly the caster of the spec c arms. You can still do the free caster mod on them though for .5* or so more.

Tony

So would you recommend switching to an 06 or earlier control arms if one was to upgrade the suspension on an 07?

[Turninconcepts.com]

Originally Posted by OA4S

So would you recommend switching to an 06 or earlier control arms if one was to upgrade the suspension on an 07?

Not unless you feel you need to. The caster can be gained back with some pretty common parts on the market.

[stretch]

Originally Posted by WolfPlayer

FWIW, I asked Whiteline this question a long time ago. Here is the response they sent back ...

Just to save people the search, those are the 22mm adjustable bars.

[STizer]

Hey All,

Sorry for the late reply.

Did some digging around. Whiteline suspension as well as other pro suspension shops, pretty much offered the same advice as what has been already discussed in the above thread.

Though....

I have managed to dig up an article from Australian derived SPEED Magazine, Issue 14, Article name: "Stroked STI". Its basically an article on the Litchfield Type-25.

There is a paragraph which states: 'At the front its more radical, with the whole strut assembly shifted forward and angled back for more wheelbase and castor, which in turn produces the steering feel that is probably the single greatest difference between a Spec C and a stock STI.'

I have a feeling this may just be referring to the geometry of the front strut/coilover when more castor is applied. It makes sense if the struts are moved forward and angled back. With the help of a anti-lift/castor kit, pillowball mounts with adjustable castor sliders, it probably makes the difference in steering feel. Maybe this is what has been talked about all along.

It also mentioned the use of the 'quick-steering gear' from the jap-spec Spec C. Is the quick-steering gear standard on MY05-MY07 STI's? I've always thought it wasn't, at least on the Australian STI. If not, has anybody heard of changing the standard steering gear to the quick gear system?

Anyway, please check this link out as well - I think it pretty much answers all the questions. It also confirms the castor specs as well, in terms of what I was saying in my above post. Whereby, the castor degree is increased by about 2.5 degrees from standard.

Type25

Cheers!

[fourdegrees]

All of the stuff you need to copy the suspension setup is listed on this page.

AST coilovers
Whiteline front and rear bars
Whiteline ALK
Spec C control arms (which I'm pretty sure were the same as the 04/05 arms, maybe the 06 as well)

I believe they also use the Spec C titanium front strut bar if you want to copy it exactly.

Just look at this page:
Type25

The extra caster comes from the ALK and control arms. That's it.

The Type 25 has been the inspiration for what I've tried to do with my car. I've asked these questions myself here and over at scoobynet.co.uk where the members actually have Type 25s. I personally wouldn't get caught up in the new spring design as it was designed primarily to cut down on the noise associated with coilovers in general.

[fourdegrees]

I forgot to add, someone did find the faster steering rack from the Spec C, but it was quite pricey. I believe it is 13:1.

[GTWORX.com]

Originally Posted by Turninconcepts.com

The Type 25 suspension is no secret. They use AST dampers with off the shelf springs, whiteline 24mm or 22mm sway bars and a whiteline ALK. That's really it. We actually started our coilover research with damping used in the AST Type 25 spec coilovers and did not like it. We also didn't like the crazy wacko springs they used. After much research we ended up with what we sell today which we feel is far superior.

As far as the caster goes, this is quite easily increased as mentioned. Install the ALK or equivalent and do the free caster mod with maybe some caster adjustable top hats and you're done. This will net in the 6* range of caster and essentually push the wheel farther forward in the wheel well.

The 07 sti uses the non spec C JDM aluminum control arms which do not add nearly the caster of the spec c arms. You can still do the free caster mod on them though for .5* or so more.

Tony

Tony summed it up well. I think the community has come a long way since the T25 was first released, and you can do better now with using the TIC Spec AST dampers instead.


- Andrew