Basic Suspension Setup/Settings

wrc

wrc

Member
Hi gents,


Searched all over the forum this morning, but maybe im being blind as it must be in front of me...



Im after a good fast road setup for my gtir. Im not a suspension guru, so please forgive my ignorance lol. My car is fitted with GAB shocks all round and unknown lowering springs, and apparently a whiteline anti lift it - Driving on 16x8's.



What I need to know is the geometery settings for fast road use, something a little more aggressive than standard as the car is only a weekend drive. My man at the garage i use (ex race car man) has asked me to bring in the 'settings' to him when I go in next week.

Can anyone advise?

Also anything else he can do whilst the car is there....?



Cheers.
 
wrc

wrc

Member
f**k..... i knew that would happen.... :doh:


saying that though, does anyone have any other input on that guide though - what theyve played with etc???
 
PobodY

PobodY

Moderators
Staff member
Not having anything on mine other than lowered springs and a couple of polybushes, I can't really comment on the bulk of that.

It's a really good guide, and set out in a logical order. - Tyres are often not given enough consideration; I don't think there's a hard-and-fast rule for pressures or selection, but I've got reasonable road tyres on mine and run 36psi at the front and 32psi at the back.

WRT alignment, I seem to contnually be chewing-out the outside edges of my front tyres so I would suggest that as close to 0 degrees toe-in is best; it feels a bit like a shopping trolley if you have too much and it will follow every bump and rut in the road.

Alignment and camber are a whole other kettle of fish; I think it's safe to say that what's best for a track car isn't for a road car, and what's best for a road car isn't for the drag strip. - Obviously if yours is adjustable you can find the settings that work for you in each situation and change them accordingly.

Whiteline say that the main effect of their polybushes is to tighten- and speed-up the response. - Think of it like this; an old squishy bush takes a lot force/movement before that's transfered. A simple way to dial-out understeer is therefore to polybush the back, and not the front of the car; this makes the rear stiffer and less prone to roll, thus it lets go of the grip before the front which is softer and can keep the tyres on the ground. It's why their upgraded ARBs are smaller at the front, and bigger at the back than the OEM units. - I guess what I'm saying is that it's worth thinking about what polybushes you're installing, and what you're trying to achieve with them.
Obviously you can achieve the same effect by having different spring/rebound rates on your coilovers, so that's more of an observation for people like me who don't have that option.
 
wrc

wrc

Member
I dont want to go crazy like yourself, George - I just want it 'right'.

I have adjustable top mounts on front, and am just about to buy some camber bolts for the rear.


As far as I can read, I basically want to tell him I want 0 deg toe front and rear, and as for camber -1.5 Front and -1.0 Rear.


Does that sound about right??
 
wrc

wrc

Member
Do you still suffer from any major understeer?

Im trying to elimate as much of it as possible with what ive got....
 
PobodY

PobodY

Moderators
Staff member
Crazy? All I've done is adjust the tyre pressure and have the toe-in looked at. - As for camber and castor, it's dead-on the standard settings; maybe a little on the negative side from the lowered springs. There's some polybushes on the rear ARB and the front wishbones, but nowhere else.

I just want mine set-up so that it keeps going in a straight line on the highway, and I don't break my spine every time it goes over a bump. If the tyres last a bit longer, that's great.
 
campbellju

campbellju

Moderators
Staff member
I wrote that so I might be biased :lol: Since then I've done a lot of testing with settings and custom mods but 95% of that simple article I wouldn't change.

As George says, first check tyre pressures and try to keep your good tyres on the front.

The alignments I wrote are still fine. 0 deg toe is difficult to get bang on and you'll always end up with +/- 0 to 0.05degs. Target zero but on the front aim for the -ve side of zero (toe out) and the rear for a road car the +ve side (Toe in).

For camber, do you have adjustable top mounts or camber bolts?

Ask the mechanic to check for any worn bushes or joints whilst he's doing the alignment.

Are your GAB's adjustable?

If you're still getting understeer and nothing else is broken then consider a whiteline rear ARB.
 
wrc

wrc

Member
Hello mate

I have adjustable top mounts on the front, and was going to do your very own 'elongating' of the top bolt hole in the shock ;-) So both front and rear will be adjustable.

MOT was only a few months ago and we looked at all the bushes, and although standard - are in good condition. My GAB's arent adjustable :cry:



So far I have the following planned:-

35psi Front
33psi Rear

As close to 0 deg on Toe ( -ve side of 0 on front (toe out) / +ve side of 0 for rear (toe in) )

Camber - -1.5deg Front / -1.0reg rear




See how that takes me, and then go from there??
 
campbellju

campbellju

Moderators
Staff member
Exactly. On tyre pressures, it depends a lot on what tyres/wheels you have and what driving you want to do. That looks fine but don't shoot me if you prefer to 2-4psi lower.
 
S

skiddusmarkus

Active Member
wrc said:
Do you still suffer from any major understeer?

Im trying to elimate as much of it as possible with what ive got....
Click to expand...
Not really fair to compare as I also have every polybush you can get, whiteline front and rear arb's, all 3 cusco braces, bumpsteer mod with rosejointed trockrod ends, a 6 point cage and a front lsd.
 
warringtonjack

warringtonjack

Active Member
skiddusmarkus said:
Not really fair to compare as I also have every polybush you can get, whiteline front and rear arb's, all 3 cusco braces, bumpsteer mod with rosejointed trockrod ends, a 6 point cage and a front lsd.
Click to expand...
With all that gear and setup, have you eliminated all problems now? Or do you still have some complaints?
 
wrc

wrc

Member
Had my ssettings done yesterday, they weren't much out but I can defiantly feel the difference.

One rear wheel was tow in, one was toe out so that was adjusted. Camber was ok so was left.

Fronts were both toe in slightly so were adjusted to tow out slightly and camber aadjusted out to -1.5 from the -0.9 and -1.3 that it was set at.


Definatly more confident at higher speed corners, and improved all round.


Therw is one thing I would like to mention though, I can still 'provoke' the back end slightly.. It doesn't feel aas sharp as the front if that makes sense - wwhat would be your suggestions from here for the rear end?
 
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