Steering / Handling feels loose
 

Im after a little advice please, but im not sure how best to describe the issue.
I am finding on long constant corners (eg motorways and junctions) that the car feels like it is going to slid out from under me. Im not going stupid speeds, 70 / 75 on the motorways, but its just like being on the edge of grip, so any acceleration feels like it might understeer and reducing speed feels like it might give lift off oversteer. As an example (for those who live up north), the junction coming from the M6 north onto the M62 east, its a 270 degree turn, but the speed I can take through the corner is about 40mph tops. I know in my old A3 I could take it at about 60. Im not trying to break speed records, but it just doesn't feel settled in the corners.

For some background, the car is MY04. It is stock OEM parts throughout but the springs and shocks have all been changed for units off a MY07. I was told at the time that they were all the same, but have since found the spring ratings changed over the years (cant just find the info in the Tech FAQ's at the moment though)
All the lower bushes have been changed for Mugen rubber items and the geo was set to UK spec about 18 months ago. We didn't do the shock or ARB bushes.
I have changed all the tyres from Goodyear F1 Asym2 to Conti Sport Contact 5's as the old tyres had done a few track days and maybe it had overworked / hardened the rubber. This did seem to help a little, certainly in the wet.

So, am I
a) at the limit of the car as it is currently set up and need to make changes to the geo. If so, what would you suggest please?
b) at the limit of the car due to the mismatch of OEM components in the suspension. Would you therefore suggest changing the springs, shocks or ARB's (id prefer not to lower it really as it goes over all the local speed bumps :))
c) something else

I think I've read some comments on here about how bad the Conti tyres are, soft and squidgy (same goes for the Goodyears), so that might be a cause.

Also check tyre pressures (that they are equal - it might also be worth pumping them up a bit more) and drop links.

As you've changed shocks and springs, I don't think it would be that.

I would agree with the squidgy of Goodyear and it was something I got used to. The Conti seem a lot stiffer. You don't have that moment as it rolls over on the sidewall (took 80psi to get the beads on the rims)
Should have mentioned, tyre pressures are all equal and set at 34psi. Drop links were also changed when we did the bushes. Not Honda ones, but one all the same.

Could there be a mismatch better the spring ratings and ARB's now, or am I just looking for an issue that isn't there?

Try getting your alignment re checked also, 18months is plenty time for it to be knocked out.

Take it somewhere decent for the alignment, do some research to get an idea of what values you want and ask for it to be set to those values, as the upper and lower recommended limits are fairly different and can produce varied effects.

As above, check tyre pressures, tyre wear and alignment. Get the alignment done ACCURATELY, not just 'within spec'. If the problem persists, then start looking at worn control arm bushes, leaking shocks etc.

I'm guessing it hasn't always felt this way to you, so we can eliminate your own interpretation of what you think the car is telling you?

The nature of the car and the diff make it feel less stable through long fast bends if you add or take off throttle compared to a front drive Audi, but it certainly shouldn't understeer under power at lower speeds.

Does it feel this way through both left and right turns? It could be something is exaggerating the steering effect of the diff? Still, that shouldn't feel like you're on the edge of grip unless you have an alignment/tyre/shock problem, something that's limiting tyre contact or position on the road.

I had this sort of feeling when I first bought the car. Turned out the rear toe was way out. And I wasn't used to the passive rear steering. Proper alignment and some rose jointed, adjustable control arms and it felt far more planted.

when I say understeer, the front or steering seems to feel very light if you try to increase speed through the corner. If you lift off in the corner, it feels like it pitches forward and the rear goes light.
i honestly can't say about left and right turns. Never thought to compare.. certainly noticed on left turns as per the example sliproad given earlier.

Didnt know we had passive rear steering :ponder:
from what people have said a recheck on the geo deffinately seems the first thing to check, then go from there.

By passive rear steer, he means the effect of the diff. The car will turn more, or less, depending on whether you are on throttle or off it, with a constant degree of steering input. It needs a consistent throttle or slow and steady changes to the throttle throughout a bend, otherwise it can feel unstable.

No, it's not the diff. It's the rear suspension geometry that is set up to toe a little further in under load (on throttle stability), but has the opposite effect of toeing a little further out under less load (off throttle nervousness). It's exactly what is being described above.

Some like it, generally confident drivers, but it can catch some drivers unawares. And some (like me) just don't like it being THAT adjustable on the throttle. Hardrace (or similar) rear toe arms solve it, as they bring the toe arms more parallel with the wishbones and pretty much eliminate the passive RWS.