My castor woes?

olliecast

Active Member
Hi everyone.
I`m currently setting up my motors handling, and looking at my previous alignment my castor seems to be very small, even with the whiteline castor kit.

I`m thinking of doing jims castor mod but i`m reluctant to if theres something else that needs doing?

I`ve dialled in more camber now but my front end alignment was as follows:

camber -> front left -1.08 front right=-0.57
castor -> front left 0.48 front right 1.21

should my caster be reading more than this, especially with the whiteline kit?

cheers,
ollie
 

gtirx2

Member
I am not sure about caster, but my camber is simular to yours if not a little worse from side to side without top mounts or camber bolts?
Where the camber is different from side to side i think it is effecting my front wheel set back as well,i have measured a millon different angles from side to side and can not find anything bent so i wondering if the gtir is made a little different from side to side?
 

geoff pine

Well-Known Member
I came a cross the paper work from when i last had mine realigned and the figures for left and right front where different i just thought that this was because it had a bump in japan.
 

olliecast

Active Member
i`m now thinking that my castor difference is because of a previous bump. I`m going to do the mild jim castor mod and see how it goes.

if that doesn`t work i`m thnking of hacking my top mounts off and placing them different so i get more adjustment - as jim has done previously

would my difference between sides make that much difference though?

cheers,
ollie
 

Mr GTiR

New Member
Humm that's odd. There should be no reason that both sides should be that far out from each other. When mine was set up by Stu and Andy we managed to dial in -1.6 on the front and -1.1 on the rears.

Jim's caster mod is deffo wrth doing. Don't worry if you don't have adjustable top mounts as once you redrill the strut top for the caster mod the top adjustable are not required and is adjusted on the bottm of the strut. This is done by elongating (sp) the bolt hole. It takes a long time to set up as it a slow process of setting them, putting the wheels back on moving the car and then measuring again.
 

olliecast

Active Member
Jim's caster mod is deffo wrth doing. Don't worry if you don't have adjustable top mounts as once you redrill the strut top for the caster mod the top adjustable are not required and is adjusted on the bottm of the strut. This is done by elongating (sp) the bolt hole. It takes a long time to set up as it a slow process of setting them, putting the wheels back on moving the car and then measuring again.
is this just due to the top mount being adjusted all the way to the back of its ajustment?
 

campbellju

Moderators
Staff member
The tein top mounts don't give enough camber adjustment if you raise them to a decent height. If you lower the car you add more static camber but you will lose more dynamic camber gain so you get into a "vicious camber compensating circle". If you carefully do my rough camber mod you can add an extra Deg or two of camber adjustment at the bottom. If you don't fancy that then look to camber bolts but I find the rough camber method is easier to setup and free. The castor mod will not work on cars without an adjustable top mount and ideally it needs coilovers for the extra clearance in the strut tower. It might work on standard struts but I've never tried it.

The whiteline anti lift kit adds a marginal amount of castor (circa +0.5degs). Castor, camber and toe are all linked on a macpherson strut car so if you adjust one you adjust the others too. The more caster you add the more difficult it becomes to get all your alignments right. IMO, our cars don't run enough castor as stock. This is my subjective opinion but most modern macphercson strut cars run more so I think its a reasonable concesus as well.

The effect you experience from 0.5degs difference side to side for caster is much less than with 0.5degs of camber. The difference in toe of 0.5degs is obviously huge! So you fix your caster first, then setup your camber followed by your toe and keep changing your camber and toe until they are correct and finish on your toe.

I actually wouldn't recommend my extreme castor mod unless you understand why having any castor works at all. The big advantage is it makes the caster and camber independently adjustable with the wheels on. The disadvantage is its a lot of effort and from my expereince the ideal setting for a car still used on the road is around the mild setting's fixed gain.
 

olliecast

Active Member
Cheers for the reply jim.
The good news I see is that I'm running tein top mounts on ss coilovers, wjitleine camber bolts and the anti lift kit. That's why I wanted to do this mod as I get considerable understeer in low speed corners during sprinting. You mention in one of your writeups about having to grind a part of the top mount. Could you be more specific as to which exact part?
Again thanks for the reply, all your setup topics have helped no end whilst getting mt r to handle better

Cheers,
Ollie
 

campbellju

Moderators
Staff member
By rotating the top mount within the camber plate, the top mount fouled when you wanted to push the top mount to the inside limit of the plate. Cutting 1cm off the top mount with a grinder did the job. Do a trial fitment and if you don't see what I mean then no problem and if you do have a grinder ready. Sorry I can't be more accurate, it's late here and it was a while ago!
 

olliecast

Active Member
thats no problem, i`m sure i`ll work it out when i come to do it. Saturday is the day i drill into my shitter!!!
 
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