I know Dales 122 has a mod that Matt (I think) suggested, which is to lower the upper control arm's inner mounting point to create some better camber gain.
I'd heard, in passing, at the time, that you felt you'd maybe gone too far, and were looking at redoing it a bit less radically on another crossmember. I don't recall you guys converting Craig to the idea, since, either?

I'm looking at doing the same thing on a spare 544 cross member I just picked up. (I say that hoping the b16 crossmember is the same as b18, aside from the idler arm mount, which I already see is different)

Doing some very basic tangent calc's, it strikes me as hard to believe that only .5 or .6 inches or whatever it was, ended up as too much?

Any help to offer, now with hindsight?

I know the locost guys use a program called Wishbone, and/or a "string computer", ie mock up using string and pushpins in cardboard. I probably should, too.

Lowering the inner pivot point 1/2" would have been pretty hard. We actually lowered it by about 2" by welding in a whole new mount made from 1" square steel. It was pretty bad for bump steer when we did it, but it did handle way better. I think the bump steer was worse because the springs he was using set the car just about on the bump stops and the suspension was well into it's camber gain at rest. With the stock 123GT springs that are in it now, it looks to be much better.

Things may be better with the "123" springs on the front...I still think I'd go with stiffer springs. There is not much evidence that the 123GT had different springs than the 122S. According to the Volvo Green book - they all share the same front suspension. I've never had my car on a track, but I suspect it would corner better than Dale's car in the "stock" position...but his car would go much better around a corner in the dropped position - more twitchy at speed, but there is a trade off for that much camber.

My current thoughts (all madness of course) is to fit an entirely different front cross member into my next project car and get away from a number of issues with the 122 front suspension.

Yes, we'll be looking at spring possibilities, keeping most of the height but increasing the rate. The stock springs will probably work pretty well with this control arm position, though - better than with the original control arm position, anyway.

Dale's car in the lowered position worked quite well, except for the bump steer. We would have addressed that with different steering arm positions, but first we'll have to get the springs sorted.

OK.... Hmm. Some random thoughts:

Any time you have the LCA so that it's pointing "up" to the wheel, you are theorectically going to have some issues. In practice though, I don't notice anything with the 142, and it's definitely at that stage of lowered...the ITB cars must be running like that are and *several* inches lower. Ideally, I'd be able to get drop spindles...

Bumpsteer...
With the ride height unchanged, just the upper inner mount points changed- can someone explain why there would be more? Camber torque of the tire sidewall?
With the right (read: generous), gain I would think you should not have to run static negative...yet the pics of the red 122 appear to show it running eith quite a bit of negative?
I'd think with the LCA level at stock height, the top of the tire can move quite a bit w/o bumpsteer per se.
I think you both are acknowledging there are two separate issues, here. The "mod", plus the amount lowered...?

Just sorting through it in my mind.

Man, I just typed in a bunch of stuff and it disappeared...Here are my thoughts. First up, I think what Matt was saying was that reverting to the stock springs (essentially) is going to help isolate a variable in the suspension of the Red car. The current set-up (when it last moved without a push ) was soft, short springs and the UCA moved down. The relocation of the UCA effectively decreases the arc that the wheel travels through - yielding more camber at rest and increasing the contact of the wheel with the ground during compression as well as a geometry change.

When compared to my car, the moving of the UCA down changed the intersection point of the ball joints and the pivot from somewhere over by the other wheel, to somewhere nearer the centre of the car.

The bump steer is probably caused by having the tie rod not moving in the same arc and giving a bunch of toe change under compression (or reverse) - more noticable with tires and the degree that they pushed the car. As the geometry of the LCA relative to the tie rod didn't change, I suspect the bumpsteer is actually what exists in all 122 suspensions - it's just more noticable as that car was running near full bump more often than a stock 122 (softer, shorter springs).

If you're just thinking about lowering the hell out of your car, section the frame horn and drop the car around the suspension. Dropped spindles are not made for the vintage guys. Or just redo the suspension.

Craig

Lots to say.

First off, by moving the inner pivot down 2", and I mean STRAIGHT down, there was no room to put shims in between the pivot and the crossmember mount. Said another way, there was nothing we could do about the static camber on Dale's car, with it at that height.

When moving the pivot down, the pivot has to move inwards to follow the shape of the shock tower, and that coupled with the additional rake in the UCA brings a lot of static camber into the equation. With the car at stock ride height, new UCA point, and zero shims, there's a bit of static negative camber already. With it lowered and sitting further into the camber gain area, it's worse.

When we moved the pivot down, I basically built a flat bar template to bolt to the upper pivot mount and that located the new pivot mount 2" downwards. Where it is, it's JUST proud of the shock tower, so it can't go any further outboard.

The LCA can point up, just fine. It's all about roll center - theoretically you want the front roll center just above (or right on) ground. To achieve this, the LCA MUST point up towards the tire! Modern cars have the LCA's pointing down for several reasons, not least of which to gain ride comfort by reducing the size and action of the anti roll bar, allowed by the higher roll center and reduced roll that comes from it. But with that (and any roll center above grade) comes corner jacking, not a good thing.

If you've got enough gain that you need no static negative camber, you've got a swing arm and probably a really high roll center. In reality, you're going to need SOME static negative camber, if only to overcome tire, bushing, and suspension flex.

And yes, Craig has it pretty right. The dropped UCA brings the instant center closer to the centerline of the car, which means the wheel tilts along a tighter arc. Because nothing's been done to the steering linkage, you get toe out under compression. You can set the steering for any ride height, but the shorter that instant center is, the more bump steer you're going to get.