Interesting that this exact discussion has just come up.
Today we raced at a new venue which had brand new carpet layed out yesterday, 32m*16m.
This meant we went from no grip to fairly high grip in one day. The track was pretty flowing.
EWCC Stock Final
I run 10.5.
Started with the following, which I used at a 'Friday' night club in a small hall, it was pretty stable but seemed to be almost too easy to drive, which meant I couln't be as aggressive as I wanted to. But other than that, fine;
Asphalt Top Deck
0 toe out
4 degrees castor
high roll center
3 holes in upper shock mount
1mm shim at c hub
Upper inside camber link mount
ackerman 2 or 3 (never can tell) and outside at steering block
5 droop (Guage)
5.5 ride height
Additive on half the tyre
shocks 4th hole in
30 wt oil
1.5 degrees camber
roll center standard
5.5mm ride height
4 droop (Guage)
1mm shim at upright
Upper inside link mnt
Additive full width
I felt the car was going off at about 4 mins and suspected that the tyres were overheating. I put the alu pillar in and this made it consistant for the whole 5mins.
Then on the 3rd run tried with the standard top deck, removed the pillar, car was certainly more on edge, but fairly stable (I had almost no steering for the first couple of laps). Other guys far better than me said it looked good on track
4th run , additive full width on front (to prevent the early understeer), but it was only on about 5 mins so the whole run was pretty crap.
5th run, back to ashalt top deck with pillar, 1.5mm front roll bar, 1.2mm rear, but grip was coming up a lot now and spent half my run grip rolling, nightmare.
Following conversations with a couple of team drivers (including Elliot Harper) I tried heavier rear oil, they were up to around 700 on Much More stuff.
So I went for 35 rear oil and 3.0 front springs and standard top deck. (THey were also using HPI gold front and silver rear springs)
Steering was superb but it had a nasty habit of snapping out when trying to carry a lot of speed through the corners which hadn't happend all day. I had to adjust my driving to the car, although it was still pretty quick I couldn't trust it enough to chuck it around.
In summary, if your running on low grip, use the asphalt top deck and stiffen the front slightly and run more rear toe.
Hope some of that is of use