bugblue1

iTrader: (3)

Hi all,ive replaced my standard suspension with pedders coil-overs haven't had geo set up as yet as no one close,any how ive still got under steer any tips on set up,i haven't slammed my car just wanted to get rid of the gap in archers ive got 17s im happy with height just got to get it level as front a bit lower than back,tyres arent wearing on edges,so any recommendations?Many Thanks Ian.

jimbo14prodrive

if your getting under steer it could just be down the tyre pressures on the front to high or make sure you get some toe out, say 5 or 10 minutes per wheel, helps turn in too. i run -2 degrees per wheel on my track car and one day i had 5 minutes toe in and under steered every corner and couldn't get the power down changed it to 5 minute toe out and transformed the car completely.

bugblue1

iTrader: (3)

Thans for the advice,do you mean degrees instead of minutes though.many thanks ian

jimbo14prodrive

Camber is -2 degrees and toe out 5-10minutes per wheel as a starting point, 5 degrees toe out would kill your tyres in no time.

bugblue1

iTrader: (3)

Cheers for the information il give it a go & see how it goes .thanks Ian

bonesetter

iTrader: (9)

Surely you mean toe-in?

jimbo14prodrive

Toe "IN" creates understeer...by going toe out reduces understeer and if you go more say 15-20 minutes toe "OUT" it can also weight up your steering and be more stable but u the increase tyre wear and put more pressure on it power steering unit, only really need to worry bout this if it's a track car...so no I mean toe out bud :-)

bugblue1

iTrader: (3)

Thats great chaps,what about ride height do you stick to subaru original height as Ive lowered mine not by a great deal just wanted to get rid of the gap on the front really i did go a bit low to start with so ive put the height back up,but is there a height you have found to work really well? many thanks ian

bonesetter

iTrader: (9)

It depends on how low you have gone with your set-up. Going 'too low' will induce understeer regardless of toe settings as the front will be in the bad part of its camber curve, effectively producing alot of positive camber during cornering, especially on the outside front wheel. Other thing your roll centre will have migrated downwards inducing more roll

Can you post up a pic of your car with its current ride height?

Do you mean you haven't re-adjusted your geo at all since changing to coilovers? You can't really start to look at throwing changes into the mix until you know what geo settings you currently have now.

bugblue1

iTrader: (3)

Hi tried to get a pic on this thread but can't don't know what im doing wrong,anyway if you click on my 2001 impreza under my user name think it will bring pic up of my car,will try & get one on hear though for you.as to set up i put my coil-overs on then took it to garage who apparently specialize in suspension came away as was told by one of the blokes id be wasting my money & i could adjust the camber my self,so took it to a Tyre place who done the front camber,i haven't slammed the car i just wanted to get rid of the gap in front archers as it sits now i want to raise front slightly to get it looking level,& as there no one close who can set it up thought id give it ago myself with any help i can get.

bonesetter

iTrader: (9)

What is the measurement between the centre of the hub to the top of the wheel arch?

As a general rule the distance should be 380mm on the front and 360 rear.

Markyscoob

Agreed. The Impreza does not like lowering at all. UNless you understand what is going on, you will not be able to figure out why.

This might be boring but stayt with me for a little bit.....

1. McPherson Strut. You car's wheels move up and down on a sliding strut, pivoted at the top. The lower link rotates through an arc that moves the lower balljoint up and down but also in and out. (Slightly fore and aft too). The in and out changes the camber of the tyre relative to the vertical of the car body.

Roll Centre.

Drawing a line through the outer and inner lower arm pivots and extending this through the car, then drawing a line at 90 degrees to the strut top inwards to cross the other line gives a point in space. Draw back from this to the centre of the tyre contact patch. Do the other side. Where these lines cross the centre line of the car, they should cross each other and this is the point the car rolls about.

More critically, do this for the back to and imaginr a pole running through both points front and back to give a roll axis.

Your car rolls about this axis. Lowering your car makes the lower arms sit more flatter. The outer end pushes out increasing static camber.

The angles change making the roll centre lower. This means the car rolls more. Bad.

As it rolls , the outer arm may move up and actually pull the bottom edge of the wheel in slightly, or realistically not push it out to counterac the car's roll.

This is very bad. You either need really strong springs which gives a crap ride, or new balljoints to change the arm angle at rest.

Caster.

Caster is good. Caster causes camber when you steer. Look at a Merc parked up with the wheel turned and how the tyres lean over due to massive caster. That's dynamic camber and gives loads of steering force for little wear...

Basically, your car needs setting up. If you just fit the coilovers, you have no idea what is going on, except it isn't right.....Toe is just the finesse at the end. if you are too low, the camber is wrong, the bolts that hold the hubs may be out too, so it's only on a proper machine that you can get all these factors dialled out and corrected.

Start with as high as they'll go, as close to standard as you can get. Then get the camber and toe corrected to O.E. specs. Finally sort your tyre pressures out and only then can you begin to chase a set up.


Note, my coilovers can transform the feel with a 10mm rear height change. This is moving the roll axis and I can feel the car lean either onto the rear corner or front corner under steady cornering load. Lowering the rear makes dramatic changes.

Most people start by trying to lower the front to equalise the arch gaps.

Did I mention the fact that the steering axis causes toe changes as you lift and lower too? Under braking, nearly every car will toe out to provide increased grip and stability. Under cornering braking, the reduction in steering angle helps to cause a touch of understeer to balance the increased grip as weight shifts.

Again under acceleration, the reverse happens. Tyres tow in to give sharper response with less grip.

You need to know where you are to start with. Go see a chassis man. There are plenty of set up info threads, and Bonesetter is there a plenty, and knows his stuff.

I have 0.2' of tow in right now, mainly because I put the whole car up 25mm for winter. It's a quarter turn out on both to get back to 0.0' my preferered static setup.

bugblue1

iTrader: (3)

Thats great for the information,I did want to get it set up properly but no one in town has a clue so wont let them touch it think nearest ive heard of is Essex & that's hundred mile away,so im just trying to learn as much as i can from anyone & everyone.so all information greatly appreciated.cheers Ian
oh i'l have a measure & put me findings on tomorrow.

bugblue1

iTrader: (3)

OK ive had a measure front turns out to be 350 rear is 370,as id said i was going to raise the front a bit anyway so i'l go with what you have said the height you have suggested & take it from there.cheers chaps

95turbowagon

iTrader: (17)

How are you finding the pedders coilovers?

Might be interested in a set, have googled them and can't see any bad reviews on them.

mantazini

iTrader: (25)

That is so opossite to everything i read/heard ....