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Old 07 February 2010, 06:58 PM
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euan_r
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Default whiteline roll centre kit

i believe this is good piece of kit for a lowered car.

would it have any benefits on standard sti6 suspension, which is a bit lower anyway. reason i ask is i have found tiny tiny amount of play in one tie rod end and will be looking to replace both this week. or should i just go oem?
Old 07 February 2010, 07:03 PM
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If you are gonna replace, replace with the Whiteline kit. Good opportunity to consider new springs seeing as the geo will need re-doing anyway etc...
Old 17 February 2010, 11:02 PM
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The rookie
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No benefit on a standard car at all, as the name suggests it puts the roll centre of a lowered car back close to that of a standard one.

An STi6 is a 'bit lower' than what? Same ride height as WRX/GX (from Subaru's own info).

Simon
Old 17 February 2010, 11:25 PM
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360ste
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Euan go for it, I fitted these to my bug last year once the alignment was done felt a good deal better.

Steve
Old 17 February 2010, 11:50 PM
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euan_r
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alright steve long time no see. hows the runs down south?

have ordered std replacements as would only be stuck getting whole new kit if a single boot etc failed later on..... cheap skate i know.

sti6 definatley has less clearance between top of tyre and arch than any of my previous imprezas, locating tolley jack is a lot more fiddly too. still got my uk turbo on eibachs and sti sits lower.
Old 18 February 2010, 06:23 AM
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Setright
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Get it bought.....if you are already considering it, this is the perfect opportunity :-)
Old 18 February 2010, 08:20 AM
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dougisaacs
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My understanding is it raises the roll centre. This effectively increases roll at the front therefore reducing understeer. I believe (not sure at all!) therefore, it will have this effect on any car. On a standard ride height car it may give oversteer? When I fitted solid front top mounts to mine they raise the ride height a bit and seemed less understeery, which would be the same effect.
I could be talking bollocks however
Old 18 February 2010, 08:27 AM
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dougisaacs
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Too clarify, lowering a car lowers roll centre, therefore increasing resistance to roll = more understeer, I think!
Old 18 February 2010, 09:08 AM
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Lowering the roll centre makes it roll more
Raising the roll centre makes it roll less.

These RAISE the roll centre - always a good idea and will help even a standard car corner flatter and help get more use of the inside tyre in cornering due to the reduced weight transfer.

I have run this kit for the past 2 years - def worthwhile IMO.
Old 18 February 2010, 10:09 AM
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dougisaacs
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I defer to you, Duncan. I did say I could be talking bollocks
Just one question, wouldn't less roll mean more understeer, in the same way a stiffer front ARB gives more understeer?
Old 18 February 2010, 10:22 AM
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It depends

Roll axis has a big part to play in that - ie height of front roll centre to rear centre as have so many other things.

Reducing roll reduces weight transfer across to the other side of the car meaning that the inside tyres are doing more work so in theory there will be more actual grip which should reduce understeer. Too many variables to say outright though and I would say that best to speak to a suspension expert such as Paul at Zen.
Old 18 February 2010, 11:01 AM
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dougisaacs
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Ooh, it's very complicated isn't it
I guess the best guidance is if people fit it and it works then great.
Old 20 February 2010, 04:57 AM
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The roll centre adjuster will indeed raise the roll centre at the front, thus reducing body roll, but by doing so (on a standard car) you incline the roll axis back (you haven't changed the rear) leading to more understeer.

Personally I would only use the kit on cars lowered by more than 1", and probably not bother (spending money elsewhere) unless it was lowered more than 1.5".

Originally Posted by dougisaacs
Too clarify, lowering a car lowers roll centre, therefore increasing resistance to roll
Oops, lowering a car lowers the roll centre even more, this means that the roll moment is increased, roll resistance (assuming spring and ARB's are the same rate) hasn't changed so the car rolls MORE.

Lower both ends of an Impreza by the same, and the roll centre at the front drops slightly further (the front arms are slightly shorter) so IF (and only if - which isn't actually the case) all else stayed the same then understeer would reduce marginally, in reality due to the loss of camber change at the front it increases.

Roll centre inclination is very important, its why for example the Prodrive blue spring kit for the WRX leaves a 4 door slightly tail high, this inlcines the roll axis and reduces understeer.

Originally Posted by dougisaacs
Ooh, it's very complicated isn't it
I guess the best guidance is if people fit it and it works then great.
You think, if those same people said that fitting the whiteline ALK had reduced front end lift then I'd do the exact opposite of what they said!

Simon

Last edited by The rookie; 20 February 2010 at 05:07 AM.
Old 20 February 2010, 06:58 AM
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Originally Posted by The rookie

You think, if those same people said that fitting the whiteline ALK had reduced front end lift then I'd do the exact opposite of what they said!

Simon
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