Evening all,

I'm currently working on the rear end of my project, and would like to stand the coilovers upright a bit more than what they currently are.

At the moment the coilover mounts from the top of the rear upright to the underside of the roll over hoop, which puts the coilover at 40°.

So I have a couple of options,

Mount the coilover bracket on top of the upper rear wishbone to the underside of roll over hoop.

Or

Mount the bracket on the lower rear wishbone (as close to the upright as possible) and then make up additional frame work off the chassis to accommodate the new position.

Input and thoughts would be greatly appreciated.

Cheers.

Why? My Luego uses the same rear set up and has no problems although it could probably do with something like 175 Lb springs when carrying a passenger

Agree with you, however on my luego velocity this set up is fine but on my XT the angle of the coilover is too great as it uses full width driveshafts

If I understand your first thought, won't that put bending forces on to the wishbone itself? The reason it's usually tied to the upright is to keep the bending to a minimum. The closer to the chassis you get the more forces will be applied (both in terms of distance along the wishbone and in terms of leverage).

I would go for a fixing on the lower wishbone, I've seen a few versions of that same idea and it seems to work ok.

It is fairly easy to calculate or luck into an acceptable spring rate for poorly designed suspension.

But mounting the coilover as upright and as far outboard as practical has too advantages.
1) Spring rate will be lower and therefore lighter – unsprung weight will be slightly less
2) The damper travel will be longer. Therefore the piston will displace more oil and the valves and adjuster provide better dynamic control.

I would mount the coilover between the lower arm and chassis. This will be a longer damper on which it is easier to mount the spring. As your new spring will have a lower rate (than you have now, for the same wheel rate) it will have more static compression and need more provision for further motion than before.

BTW I have no experience of this Luego and offer some theory to aid your decision.

Slimy38 - fixing it to the upper wishbone was purely for ease, I have never seen it done like this hence the reason for asking. I have however seen it mounted on the lower wishbone.

Camberdave - yep agree, although I would need to add additional box section to make a new top mounting position for the coilover.
Which is probably the way I will go as I've not seen my idea on anything else which makes me think their must be a reason?

Sorry, didn’t realise yours is an XT .I believe the basic chassis is the same and the bodywork? Moving the upper mount further out might involve moving them out side the body which may cause problems? Would it be possible to modify and reinforce the rear uprights so the lower mount is closer to the centreline of the car? Bear in mind some of the Luego rear uprights had a problem with bending , mine did so I removed them and used a press to straighten them before welding a reinforcing band around the inner side of the upright. Later Luego’s had a reinforced upright

Rusty nuts - I am making some new rear uprights as the ones that are on the car are a bit pants.

The issue with designing in the mount for the coilover, is it would have to be about 100mm in from the upright face and to then gusset that could possibly cause a problem with bolting up the top wishbone.

I'm going to have a play around with different designs and see which is best/preferred.