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Dialing out understeer

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Old 04 April 2011, 09:37 AM
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Turbotits
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Default Dialing out understeer

Had my first sprint race this weekend which was great and no major miss haps which is a goos start.

Ive always been pretty happpy with the handling of my car on the road and its always gone where i've pointed it. lol
Sso first sprint and wow the amount of undeersteer i have is awfull. Now it may ofcourse be i was putting into corners to hard and need more practise at slowing the thing down.

Anyone got any good tips in how to set it up slightly different or what to change?

Spec is a 2002 sti

Has bc coilovers and has all been set up on a 4 whel alignment system with a fair amount of neg camber

Think i may start with some solid drop links
Old 04 April 2011, 10:58 AM
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HRT
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Hi

I had the same issue with my car. Great on road but on a go kart track with really twisty bits it was crap.

I started a thread under Suspension - Understeer what suspension upgrades next. Sorry do not know how to link it in.

It has a good bit of info from various people. Main thing that I found in order of benefit

Driving style - definitely driving too hard makes you really slow.
Less power - I am all over the place on high boost on Toyo T1-R. Too much wheelspin and oversteer. My times are better on low boost. Better tyres may change this.
Tyre pressures - I found to be very important and make a huge difference to the understeer and grip levels.
Rebound rates - I am definitely faster with a softer setting at the front and harder at rear.
Ride height - Too low means you are too slow. This was the first thing I increased only by a cm all round but the car feels much better, and I was over 1.5 sec faster just with this change on a 60sec course. Also is better on the ****ty roads.

I have not delved into camber/toe settings as yet. I have only just bought the Whiteline kit and have yet to have it fitted.
Old 04 April 2011, 12:30 PM
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Turbotits
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Thanks for the reply some things for me to try
Old 04 April 2011, 01:24 PM
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Markfey
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I have a classic and i have looked in to this.

I have spoken to many people (Opinions) and experts including FB Tuning and powerstation.

The general consensus seems to be Whiteline products i.e adjustable front and rear roll bars, solid drop links and antilift kit followed by laser alignement.

Hope this helps.

Since seeing Rich at FB I'm still dersperately saving for all the goodies.
Old 04 April 2011, 02:03 PM
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great i think thats where im gonna start with some solid drop links. Had a read of HRT's thread and some interesting stuff there. My car is lowered a little but i think im gonna raise it up a little as i did feel it was maybe on the bump stops once or twice. Also i read that hardening the back up helped and i did the opposite half way through the day in that i left the back soft and hardened the front up. so i have lots to try
Old 04 April 2011, 02:12 PM
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stef_2010
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Originally Posted by HRT
Hi

I had the same issue with my car. Great on road but on a go kart track with really twisty bits it was crap.

I started a thread under Suspension - Understeer what suspension upgrades next. Sorry do not know how to link it in.

It has a good bit of info from various people. Main thing that I found in order of benefit

Driving style - definitely driving too hard makes you really slow.
Less power - I am all over the place on high boost on Toyo T1-R. Too much wheelspin and oversteer. My times are better on low boost. Better tyres may change this.
Tyre pressures - I found to be very important and make a huge difference to the understeer and grip levels.
Rebound rates - I am definitely faster with a softer setting at the front and harder at rear.
Ride height - Too low means you are too slow. This was the first thing I increased only by a cm all round but the car feels much better, and I was over 1.5 sec faster just with this change on a 60sec course. Also is better on the ****ty roads.

I have not delved into camber/toe settings as yet. I have only just bought the Whiteline kit and have yet to have it fitted.

I bookarked it for future reference

https://www.scoobynet.com/suspension...rade-next.html
Old 04 April 2011, 04:08 PM
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dunx
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What tyres did you use ?
Old 04 April 2011, 04:26 PM
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Originally Posted by Markfey
I have a classic and i have looked in to this.

I have spoken to many people (Opinions) and experts including FB Tuning and powerstation.

The general consensus seems to be Whiteline products i.e adjustable front and rear roll bars, solid drop links and antilift kit followed by laser alignement.

Hope this helps.

Since seeing Rich at FB I'm still dersperately saving for all the goodies.
Apart from the front ARB this is what I did to my Classic and it had loads less understeer.
Old 04 April 2011, 06:58 PM
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Originally Posted by dunx
What tyres did you use ?

Tried a couple of different sets to be honest all with pretty much the same results. Started on the fairly average roads tyres i had on which were falkern 452's, then switched to a worn out set of toyo's tr1's then borrowed my mates khumo track day tyres/wheels. i do have the feeling i was maybe to blame in that i was to hot into the corners and asking to much of it and should have scrubbed more speed of prior to them.

On a couple of corners i was able to chuck it in hard and make the back step out and basically power slide round them which was great fun but probably not the quickest way round them

Last edited by Turbotits; 04 April 2011 at 07:01 PM.
Old 04 April 2011, 07:25 PM
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When my car was first done by Powerstation many moons ago, I was told to stiffen the rear arb, leave the front alone.

Mine now runs 22mm rear adjustable on mid-setting, solid droplinks all round, ALK, and bumpsteer mod, plus better bushes.

Since then it's on BC coilovers and has had the geometry re-done at carnetix after the coilovers were fitted.
Old 04 April 2011, 08:31 PM
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dunx
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It all depends on how serious you want to be, IMHO.

On my 2002 STI I run 22mm adjustable ARB's at both ends, ALK on the front but at almost std. ride height on the Teins. Oversteer is available if you "chuck it in", but it's mostly planted on R888's.

By going for a more aggressive geometry set-up you can make the car do what you want, but that may be at the expense of higher tyre wear on the road.

HTH

dunx
Old 05 April 2011, 08:18 PM
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Turbotits
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Originally Posted by dunx
It all depends on how serious you want to be, IMHO.

On my 2002 STI I run 22mm adjustable ARB's at both ends, ALK on the front but at almost std. ride height on the Teins. Oversteer is available if you "chuck it in", but it's mostly planted on R888's.

By going for a more aggressive geometry set-up you can make the car do what you want, but that may be at the expense of higher tyre wear on the road.

HTH

dunx
Great i thinks thats what im gonna do. arbs and probably add a degree or to of neg camber on the front. I guess i can do this via the adjustable top mounts to get it just how i like? And then pull it back for road use
Old 05 April 2011, 09:00 PM
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AFAIK, if you muck about with the top mounts settings, apart from rebound stiffness, you need to get the geometry checked?
Old 05 April 2011, 11:45 PM
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A wiser man than I advised swapping top mounts from left to right before fitting to allow even greater castor.

A tweak I may try next as I'm all cambered out currently.

dunx
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