Magic - thanks very much. I'll see if Kris from RSS can source these along with an STi rack.

Hi James,

Definitely the ALK. I have STi suspensions as well but the slight increase in NVH is noticeable but bearable. I then fitted the RCA and ALK while waiting for the suspension to settle in to the new ride hide before swapping the old Geosqueelers for Michelin Primacy and alignment. The feedback from suspension is immense bordering intense, every chatter from road imperfections felt and potholes are now jarring. New tyres helped as they are made for comofort.

Would love to know alternatives too but Group N bushing is out of question as I love the extra castor and I can live with it for now.

You could also apply CLD (constrained layer damping) to minimise vibration and resonance in the chassis, which is more prominent in wagon/SUV than sedan like your STi. I had it way before the suspension mod as the Geosqueelers were terrible with road noise. All the crashing and jarring sound that you mentioned are muffled.

Here's more info on sound deadening https://www.sounddeadenershowdown.com/

QUOTE The best way I can explain it is quite violent "crashing" or "shock" being transferred into the body of the car - specifically when going over crappy sections of road (ie; botched potholes etc), metal grid lines (the flat kind - like on bridges etc) or cracks in the road. ENDS

James your referring to just about every road in Queensland!

Craig might have the answer?

Cheers Al

Hmm i have pedders bushings in my front lower control arms. maybe that is a source of the banging and crashing when i drive.

I have the AVO Castor Correction bushes and they did increase NVH. I like to think that I can "feel" the road better now.
The Castor correction was a definite improvement over stock though.

I've also just recalled that the mechanic from John French Motors, a reputable Subaru garage in Brisbane, told me that they use stock rubber bushings for their race cars as they are good enough and doesn't add unnecessary NVH

Hey Vintec, I'll probably take the punt and put the stock bushes back in if I can't find any GroupN bushes (or if it's too hard/expensive to get them). A bit of a shame because they do what they're meant to but the trade-off isn't worth it IMO, not for what we're using the car for anyway.



I'm running about 6.5deg castor already and I have the Com C top hats which provide some castor adjustment as well, so I may be OK if I lose the ALK.



It's so smooth on decent roads but when the going gets rough - I feel every hairline crack, every rock and sometimes even the road paint!

I thought Whiteline product description says only 0.75 deg of castor? I'll seriously consider the top hats if they really allow 6.5deg of castor. Is that on STi or stock suspension?


I know how you feel (no pun intended), the vibration is so intense I'm surprised the car hasn't disintegrated yet

Looking at my alignment spec sheet after I fitted the MY08 STi struts/springs, my castor was 6.51 left and 5.84 right. They made no change during the first alignment which was after the ALK and RCA kit went on. When the Com C top hats were installed, my castor improved to 7.1 left and 6.5 right with the top hats positioned for maximum camber. Fulcrum recommended to opt for an increase in left castor to compensate for the angle in the roads (leaning towards the left gutter), but looking back at my STi spec sheet I was running about 5.8deg equal across the axle and that was perfect for that setup.

If I lose a degree or so in castor I won't be too concerned. The trade-off to gain some comfort will be worth it.

Update - I've ordered the LCA inner rear bushes (Part# 20204ZR010 x 2) from japanparts. Will report back when I've had them installed with an accompanying alignment. Interested to see how much castor I lose by removing the Whiteline ALK - may be able to rotate the Com C strut tops to compensate - can't quite recall if they're on max castor/max camber or just max camber.