I'm hoping to take a trip to Powerstation next month (their work-load permitting of course) to get some suspension mods done...

New KYB shocks (standard Excel-G gas struts, cant afford much else)
Eibach springs
STi top-mounts
Probably bump-steer mod (read way too many +ve reports to ignore)
Full geometry set-up.

Id also like to throw in an anti-lift kit while I'm there.

Whiteline offer both Comfort (KCA361) or standard (KCA319A) kits.

What do most of you guys have fitted (if you have an alk of course)? Any NVH issues with the standard kit (KCA319A)? I'm trying to keep my car reasonably comfortable and the roads around here are badly falling apart.

Anyone tried both?

Many places stock the standard, but there seems to be a wait for the Comfort version. Is this an indication as to which is most commonly fitted (standard as its more easily available)?

I'm running a MY99 UK Turbo2000 with standard suspension except Whiteline steel rear drop-links. I will eventually get a 22mm rear ARB and uprated mounts, but I'd like to get the springs/struts/etc fitted first.

I've had a search through the forums, but most alk threads end up with a discussion as to the misleading name of the kit

Any experiences most welcome!

 

Use the standard kit.

Mine have been in for about 4 years now with no issues, no noises/creeks/groans.
The comfort kit has softer bushes, but that defeats the objective a bit.


Power Station will advise you when you call them.

Graham

 

I had a feeling (and actually hoping) you'd reply Graham!

I'm a regular lurker on here and always find your replies informative and polite. After bad experiences with other forums (not car-related), its a refreshing change (all you guys and gals on SN seem pretty decent! )

I'll probably go with the standard kit to be honest. As you say, if the bush is too soft it will defeat the purpose of it. I'll still see what PS have to say, but I'm pretty sure they'll say the same.

Anyone else with experience of either?

 

Comfort are hard to get hold of. In the end everyone just gets the normal one and it's fine. As Graham says, it's not a big issue, really it's not. I've got a very similar spec to what you're aiming at in my MY98 WRX wagon and it drives lovely - the same KYB gas dampers, Eibach springs, Whiteline ALK and 22m ARB on the rear and alloy droplinks both ends. Then Whiteline geometry as well. I commute to work in it, take it on long motorway cruises, hack it around the country back roads at full pelt and go down the shops with wife in the front and baby in the back. I'd soon hear complaints if the ride was no good LOL.

 

What is this bump steer mod you talk about?

 

Bump Steer is when your wheels steer themselves without input from the steering wheel. The undesirable steering is caused by bumps in the track interacting with improper length or angle of your suspension and steering linkages.

Most car builders design their cars so that the effects of bump steer are minimal. However, you must still take care to bolt on your suspension carefully so as not to create unwanted bump steer. Make sure that you are always using the correct components for a particular car. Bump steer must be designed into the car and cannot be adjusted out if improper parts are used or if pivot points are moved without considering bump steer design principles.

In order to accomplish zero bump the tie rod must fall between an imaginary line that runs from the upper ball joint through the lower ball joint and an imaginary line that runs through the upper a-arm pivot and the lower control arm pivot. In addition, the centerline of the tie rod must intersect with the instant center created by the upper a-arm and the lower control arm (See diagram below).

The instant center is an imaginary point that is created by drawing a line from the upper a-arm ball joint through the a-arm pivot where it is intersected by an imaginary line that extends from the lower ball joint through the inner control arm pivot. Where the two imaginary lines intersect is the instant center.

Sounds complicated? Really it is very simple. To achieve zero bump the front end must be designed correctly. The tie rod must travel on the same arc as the suspension when the car goes through travel. Simply matching lengths and arcs to prevent any unwanted steering of the front tires.

To exaggerate, if the tie rod were only 10" long and the suspension were 20" long then when the suspension traveled the tie rod angle would shorten much quicker than the suspension arc. In this scenario the tie rod would shorten much quicker through travel than the suspension and the car would toe in drastically over bumps. The shorter arc of the tie rod would pull on the spindle and toe it in through travel.

Bump Simplified - When designing a car, if the centerline of the outer tie rod lines up with the centerline of the lower ball joint, and the inter tie rod lines up with the lower pivot point then the length and angle of the tie rod and suspension will be the same resulting in zero bump. Most car builders design their cars in this fashion.

 

See above for the encyclopedic version...

In Impreza (normally Classic) terms... The suspension is setup so the outside front wheel understeers as roll increases. It's apparently designed that way and is meant to be "safer" on average... IMO it's not safer if one deliberately goes in search of the edge. And the suspension can unload in some situations leaving you with too much lock on or too much of the wrong lock on.

The "bumpsteer mod" is an accurate measurement of the steering deflection in roll (done by compressing the spring or sitting a fat bloke on the front wing ). Then the steering rack is shimmed on its mounts to minimise the effect.

Normally coupled with an ALK fitment and/or a 4 wheel alignment session.


J.