5 replies to this topic

[Xurana]

Hi all,
I've owned and still own a LJ gtr but have now bought a LH 4door that is 355, 9" with commodore rear disc brakes, and standard disc front, i have just had fitted a TKX600 5 speed. I'm now looking at sway bars and suspension upgrade that will then lead to a aftermarket full set of brakes im sure.. is there a go to suspension package that seems to work for a street car that will very rarely do a track day. I was thinking maybe kmac sway bars and maybe bilsten or koni shocks. At the moment it has pedder shocks with kings ultra low springs. And advice would be awesome cheers..

[Peter UC]

For brakes just go a Hoppers kit on the front, they are simple, work well and because they use factory parts are easy to get pads etc for.

 

For suspension, it depends on how you are going to drive it and also what's there already.

Sway bars I would recommend:
Rear: None (my preference for standard rear suspension geometry) or maybe a standard one (UC style is preferred) I wouldn't go bigger than stock unless you're doing a lot of drag racing.

Front: Realistically, as long as the pipes fit, a 24mm bar in the the stock location will work well, otherwise probably the Kmac one if you need a front mount.

Shocks:

I prefer Bilsteins to the Konis, especially on the front, See if you can get the fronts revalved as well they're not perfect out of the box (although still OK), I'm using Shockworks which are more money but are definitely a step up.

Springs:

For some sporty street driving that still rides OK go for around 800lb from and 200lb rear. Add or substract spring rate to suit your preference but try to keep around 4:1 ratio between front and rear spring rate (wheel rate will be about the same this way)

Also alignment is pretty important. Being a LH redrill the upper front control arm mounts on the cross member as low as they will go to get some camber gain (use a 7/16" drill bit) and get it properly aligned

I like the following settings on the street as it works well for me (although i do push pretty hard so most people should probably use a bit less camber)

-1.4° camber

+3° caster (you may not be able to get this much out of the LH/LX upper arms but you should be able to get 2°+)

2mm toe in.

Edited by Peter UC, 15 August 2024 - 02:42 PM.

[yel327]

I'd try and swap the upper arms out for UC ones while you are there. Might mean UC steering arms too, Peter will be able to guide you on that. Peter, do you have to drill the mounts lower if you use UC upper arms? I remember on my LX it had the mounts up really high like a UC (higher than LH), with UC upper arms the minimum camber I could get (no shims) was -0.5deg. A couple of shims would easily see -1.5deg.

[Peter UC]

LH - UC all use the same cross bar for the upper arms. The UC actually has the highest mount point for the upper arm as the engineers at the time wanted a static camber curve through the suspension travel. 

[yel327]

I knew UC is the highest, GMH had to modify the top of the upright part of the crossmember to allow the holes to be drilled/punched for the upper arm mount. What I meant was do you have to lower the LH holes if you use UC upper arms? UC upper arms by themselves reduced camber on my LX drastically over standard LH-early LX. That was with HK-WB stubs though, not Torana, but it was with the factory UC upper arm mounting location. I actually modified an RTS LX front crossmember to be the same as a UC so it had the really low LX RTS location holes and the UC high holes.

[76lxhatch]

The top arm mounting height is about camber gain throughout suspension travel rather than the static setting. At ride height I'd run 1 degree (negative) or a little less if you have low profile tyres and/or a good amount of positive caster - if you can't get enough caster another option is an adjustable bushing in the front of the lower arm which also brings the wheel back to centre. It's really about the combination rather than any individual thing, same with front and rear anti-roll bars.