DonNedly

iTrader: (10)

I'm looking for an alternative to the whiteline roll centre correction kit and wondered if anyone has fitted these?
http://www.apexperformance.co.uk/cat...4e36c45e516f73

Can anyone vouch for the quality?

DonNedly

iTrader: (10)

wow, that many of you(!)

DonNedly

iTrader: (10)

really, nobody at all!?!

bonesetter

iTrader: (9)

You don't like the WL ones?

DonNedly

iTrader: (10)

I don't fancy the bump steer correction that comes with it and rather than buy stuff i don't want it seemed better to get these.
Unless whiteline sell the ball joints separately?

bonesetter

iTrader: (9)

I agree with you on the track rod correction - very suspect benefits.

I remember a thread I posted on about alternative extended ball jt's, I'll see if I can find it

Those ones you list look OK to me

Edit: Here ya go - some good reading


.

Sheepy Sean

iTrader: (1)

Sorry to hijack but how much would you need to have lowered your car by before these are a worthwhile purchase? I have a 2006 Hawkeye STI which is now running on pink STI Type RA springs I think im only about 15mm lower than standard. Would these be any benefit to me?

DonNedly

iTrader: (10)

lol. i think that thread is where i found out about these ones.

They look ok but i'd feel better if there was someone out there actually using them.
Maybe i'll be a pioneer

DonNedly

iTrader: (10)

You won't need them for that small a drop. I'm planning to drop as far as my wheels/front bumper will allow

Superpro ones here: http://www.scoobyparts.com/acatalog/...TMENT_KIT.html

but they have the tie rod ends too. Could just bin em i guess?

Sheepy Sean

iTrader: (1)

Heck of a lot lower then me then!

Thanks, am going in for a geometry set up in the next few weeks so wanted to get the ball joints beforehand if they were going to be of any use.

bonesetter

iTrader: (9)

SuperPro stuff is usually OK

DonNedly

iTrader: (10)

Just read this: http://www.subyclub.com/index.php/to...e-fail-kca313/

Not big fans of the whiteline there!
Found the superpro ones for £92 from Halo performance so that'll do me.

bonesetter

iTrader: (9)

It's a sad fact, WL quality is not what it used to be. Manufacture has been farmed out to Asia and tolerances widened. The original members have sold, so alot of the R&D is not bienfg carried forward as it once was

Cheaply made (expensive to buy) shiny bits...? Even the arb's have had their share of issues with badly bent bars etc

legacy_gtb

iTrader: (3)

If your lowering that far, your handling will be up the swanny anyway! 10mm drop for a track car is usually about right, 15mm max.

By lowering too far, you incline the wishbones and lateral arms too much, giving lateral scrub and track change with suspension movement. Amongst other things this means that some of the cornering force is loaded into the spring, reducing compliance and grip.

The roll centre adjust BJ's will help this if you dont go mad with lowering it, but its a much harder task to adjust the rear to match the front as its not just a case of bolting new bits on!

You want the steering to be influenced as little as possible as the suspension moves through its motion, which means the roll centre adjust track rod ends and BJ's go hand in hand to avoid bump steer.

I fitted the whiteline RC kit, and moved the rear lateral arms inboard pickup points up 10mm, this with a 15mm drop seems to work well, but havent had a chance to use it in anger yet to find out.

This is just my 2p by the way.

DonNedly

iTrader: (10)

I'm not gonna slam it to the floor. I meant as low as i can but still get on my sloped drive without scraping the front bumper so probably start with 30mm all round and then have a play from there really.

I'm hoping a 30mm drop + rcc + alk + arbs + droplinks + free caster mod + geo = Happy days on the track.

legacy_gtb

iTrader: (3)

Let us know how you get on!

Im of the opinion that 30mm is just too far for semi standard chassis points to work, but interested to hear your findings.

bonesetter

iTrader: (9)

Have you got coilovers fitted? Leggy has got q good point about over lowering. Too low and your expensive goodies will count for jack

legacy_gtb

iTrader: (3)

I was assuming that there were coilys envolved, otherwise there must be rucks of different rate springs kicking about!

DonNedly

iTrader: (10)

yeah, sorry, bc coilovers are on their way but i don't want to pay for more alignment than necessary so trying to get everything on in one swoop.
Next track day isn't till 31st August but doing a little 1/4 mile up and back sprint event on 29th July so i'll see how it goes.
Its a pain because i hate it looking like its on stilts but i want the best handling i can get.

bonesetter

iTrader: (9)

Don, I would very strongly advise you against slamming your scooby, except for looks only

BC coilovers can 'work' as low as you set them as the whole damper cartridge lowers so you don't lose dampere travel. However, you will be going into the 'bad part' of the camber curve and badly affecting handling. You'll almost certainly get understeer, poor overall front grip etc.

See this thread for good reading, esp what Arnie has to say on ride height

As a general rule aim for bottom of wheel arch to wheel/hub centre

Classic F 350 R 345
01-04 370 360
05 380 360

(figures as per Job G )

jura11

iTrader: (7)

We are running like coilovers and Whiteline KCA313 with ARB's FR 22mm and RR 24mm,before handling has been not the best without the KCA313,this simply transformed car/wagon

We are tried several alignment setups and at the end we are went with FR -2.00 and RR -1.50 and looking like we have best for like fast road,drag and track days

Before without the KCA313 front end has lift under heavy acceleration(we have fitted too WL ALK)

If you are lowering the car,I would go with the KCA313 or any Roll Centre/Bump Steer - Correction Kit,if car is not lowered I wouldn't brother at all or you are making car just for look






Jura

DonNedly

iTrader: (10)

point taken guys. A scoob is for driving, not looking at; so i'll try to not get carried away. Thanks for the link too bonesetter, good reading.
What happened to Arnie? He really knows his stuff!

Mine is an 05 wrx so how much of a drop is F 380 R 360?

Jura: "FR -2.00 and RR -1.50" is that your drop in cm?

Sorry for all the questions, it is a black art this handling malarkey.

JDM_Stig

iTrader: (3)

thats camber settings

bonesetter

iTrader: (9)

That figure is what you're aiming for. Not sure what std height yours is

Jura's camber settings are to suit his useage. Good thread on geo settings here

Happy fettling Let us know how you get on

Arnie_1

I'm still around, haven't had time to cruise the forums lately.

The Impreza chassis can be a bit sensitive to ride height and geometry. Some times "good handling" is something that most folks wouldn't know if it bit them on their danglies. Often times people think "handling like a go kart" is a good thing. But it doesn't mean you have more grip and are actually faster around a corner. Lowering the car is theoretically a good thing, lower center of gravity and all that. But like you've read its not as simple as all that when you look at the dynamic aspects of the suspension geometry.

Standard ride height according to the service manual is (this was bug eye, but its about the same throughout the entire GD run):

Front 396 mm +/- 12mm, Rear 376 +/- 12mm (STi is 386mm F/366mm R)

Here's some general ride height specs for the various models:

Classic front 350mm rear 345mm
01-04 front 370mm rear 360mm
05 front 380mm rear 360mm

On the whole, it will look like doodoo compared to a properly flush and tucked impreza but it will handle better. You can go a bit lower but you'll need to start using geometry correction parts like RCA's, or massive spring rates to keep roll at bay (which has its own drawbacks).

As bonesetter alludes to, your end geometry will be completely up to your particular usage/tyres/tastes/components. For example if you're just doing mostly A-roads on all-season tyres, your alignment spec will be very different from B-road blasting on sticky summer tyres. Naturally tyre wear can also be a factor. So keep that in mind when you decide on your final geometry spec.

Basically, there's no free lunch. Suspension is indeed a complicated thing where all components work together for the whole. You can't change something and not expect a potential adverse effect someplace else. Just read as much as you can so you have a basic understanding of what affects what before you start spending money. Then you can make informed decisions about what parts to get and how to set them up. Its that last bit of fine tuning however that can really bring it all together.

DonNedly

iTrader: (10)

Wow thanks for that arnie. Plenty to think about.
I picked up my coilovers today so thats the hardest part over with for my wallet.
If i go for a more conservative 20mm drop do yoy think a rcc kit will be beneficial.
The car mainly does a road blasting on toyo tr-1s and track sessions on hankook moulded slicks. 17s for now but may go for 18s at some point.

Part of me wants to just fit the coilys see how they feel and then add the rcc and alk later so i can feel the effect they have. If only geo wasnt so bloody expensive.

Arnie_1

Personally, I think RCA's are good for any level of lowering because you are going beyond the manufacturer's original design intent and geometry setup. I'm sure someone has actual data that shows exactly what the roll center migration is per amount of lowering. I don't have it. Its just my gut and butt dyno feel. Heck, I even noticed a reduction in front end roll with stock struts/springs when I took off my coilvers for servicing. A benefit with the RCA's is to be able to run softer spring rates at a lowered ride height because you aren't having to use large spring rates to control roll (over-lowering and lowering your roll center will actually increase the amount of body roll your car has despite having a lower center of gravity).

I'd say just fit the coilovers for this year and drive it. I personally prefer to put on parts one at a time so I know what effect they have on the handling. But I've learned to do my own alignments on my driveway so it saves a bit of money on geometry setups.

Just optimize your coilover setup with your chosen tires and driving conditions and learn it. After a season of use you can then better assess what you might want to further improve, knowing there are still a few tidbits that can take you to the next level. If you do hit the track, make a note of your laptimes. That way you can have some kind of objective standard to base improvements on when you put on new toys.

I'm a big proponent on education; learning your car, installing your own parts, etc. etc. So more chance you can give yourself to learn what these parts do and have the seat time to verify it, the better.

One should get one's geometry checked once a year anyway (I would suggest after winter) so you can budget that in for your ALK or RCA's.

I also wanted to say in regards to ride height, that to a point its pretty much a personal thing. We all want a cool looking car so you'll have to decide on aesthetics vs ultimate performance and find a happy medium for yourself. Just don't go lower than 350mm (center of hub to fender, btw) up front. Things really go pear shaped after that. I personally never go lower than 355mm F/345mm R on my bug eye.

though while you are at it, I would rotate and flip your camber plates so that you can get more caster from the get go.

Arnie_1

Here's a quote for someone who has rotated his camber plates:

DonNedly

iTrader: (10)

Thanks so much for the advice. Very comprehensive.
There aren't too many people on here that would put that much time in to their responses. Cheers.
I'll definitely rotate/flip the camber plates and just see how the coilys feel for now.

Arnie_1

Cheers! Its all about sharing info with each other and passing it on. Now you know more than you did a week or so ago and you can help out the next chap with your experience. Or at least point them to your thread here!

I'm sure a lot of this info is buried in the archives some place but its not a problem to spell it out again every few years. Besides, little things change over the years as new data points from people's experiences are compared. So its worth typing this sort of stuff out again with fresher eyes. I think about some of the things I wrote 12 years ago and cringe!