13 replies to this topic

[76lxhatch]

Yes you can use the LH one, but there are some differences in geometry and handling between earlier and later models so depending on what you're after you may prefer to get hold of something a bit better. There are a number of topics on this subject around here, such as this one:
http://www.gmh-toran...showtopic=14102

[Heath]

And a different rack ratio and inner pivot point on the top arms. Read up and figure out what would suit you best. An untouched UC rack is not ideal.

[76lxhatch]

I don't know what Heath is talking about, they're the pick of the bunch

[Heath]

Yeah the ratio is one part

I don't own a UC crossmember but I was told that the mounting studs where that bar gets bolted onto the crossmember to have the top wishbone pivot around it, were located really high on the UC setup, and you want to pull it apart and redrill them to be lower down, I guess to control the camber differently.

OOTB they are not ideal, But yes I do realise that they have metal bushes on the rack, top balljoints located a bit aft on the top wishbones and a pair of steering arms that provide less bump steer, or so I have heard!

[its Paul]

Hi Mark, welcome to the forum, if your restoring your Hatch, slow down take as long as it takes and do it right, you will be much happier in the end.
Find a UC front end, follow the guide in the above post, get it painted or powder coated, you will be much happier.



Cheers.

[76lxhatch]

they have metal bushes on the rack, top balljoints located a bit aft on the top wishbones and a pair of steering arms that provide less bump steer, or so I have heard!

Actually there are no bushes at all on the rack, just smaller mounting holes for the bolts only. The steering arms sit the tie rod end slightly further forward and a bit lower to make up for the increased caster - for a setup with a decent amount of caster this would be less bump steer compared to LH/LX arms, but not necessarily for a factory LH/LX setup. I.e. no particular set of steering arms is better for bump steer, they need to be matched to the suspension/settings.

[Heath]

Okay cool, all of that was going off what other people had said as I don't actually have a UC front end, but it looks like my understanding was essentially alright

[ls2lxhatch]

I also have my doubts regarding the benefits of moving the upper control arm to the lower mounting point with standard UC suspension.

The general consensus is that the lower position is better for a track car with HQ stubs. However the HQ stubs lower the car 1" which basically alters the suspension geometry. Larger bump stops were added to reduce upwards suspension travel by approximately 1".

The lower position may be the ultimate position for a race car with HQ stub axles, it may also be the ultimate position for a street car with HQ stubs. However it may not be the ultimate position for a street car with Torana stub axles.

It would appear that the designers found that the optimal position for a street car with Torana stubs is the high UC position. The question is why? Did they feel that the car suffered from over steer and wanted to increase under steer or was there some other benefit?

[76lxhatch]

I think its a matter of allowing maximum adjustment too, I've seen at least one front end with no shims at all that still has excessive negative camber (quite low though) when using lowered holes with Torana stubs and UC upper arms.