When should the ESP kick in?

[Druggie]

First drive in the rain 2 days ago and while on my way home along failiar roads i arrived at a 2 lane wide roundabout and takled it at what i thought a slow pace with very little trottle (pace was much slower and with less acceleration i used to tackle it with the suby) the front started to understeer.
Should the esp have kicked in?
Or is it useless once the tyres loose traction?

How can i test if it is working? (obviously not on public roads)

[Dippy]

I admit I don't know much about ESP, but I do remember that the stock S4 will understeer. This must be a problem with the suspension because the H&R coilovers removed it for me.

I generally don't notice the ESP except for basic traction control either on icy roads or when the weight is unbalanced (e.g. coming off a hump-backed bridge). So I think it does give you a fairly good envelope before kicking in.

[S4 OXON]

I also have 2001 S4 avant with ESP. I've only had the car 8 months and it's only when you push it hard in the dry and have a bit of space (just in case) like a small roundabout which is very tight and accelarate hard. The first time it happened to me it cut the power and I thought I'd broken it. Now the tyres are low it does come on more in the wet when you drive it hard but it's good to know what and how it feels. There is more on this in the rs4 forums under ESP I think.

[DavidR]

In the wet, the S4 ESP will allow a lot of understeer to build before ESP intervenes. I have driven a few really wet trackdays, and you can understeer with almost a half turn of extra lock on before ESP gets interested... It's much quicker to address oversteer, although, you'll still need to be 5-10degrees sideways before the ESP works.

[KayGee]

Never?