This is a high-performance coilover setup. It would be foolish to get prorgessive or soft springs for this. If you want comfort, get the BAT or Koni kit. If you want something faster than GCs and Konis, this may be for you.
Spring rates
Code:
kg/mm lb/in N/m
3.5 196 34
5 279 49
7 391 69
9 503 88
11 615 108
13 726 128
15 838 147
18 1006 177
22 1229 216
Here's my take. These are just basic sets, but should work as outlined below.
DD with stock swaybars: 7f/5r - extra rear roll stiffness without swaybar hassles!
with Aussie bar: 7f/3.5r - same f/r bias as GCs, but softer.
both of these should give you most of the performance of the GCs without the super-harsh ride. Probably a little stiffer than the stiffest non-coilovers available, but I dont' ahve numbers for them, so I'm not sure.
Sportier/race/track setups:
9f/5r - essentially the same as GCs. Not bad if you already have the Aussie and are on the street or track.
9f/7r - more roll stiffness in the rear than GCs - great especially if you have a stock rear swayabar, but should be well-balanced for autocross use with the Aussie. I'm thinking of converting my GCs to this rate.
11f/9r - just stiffer than the 9f/7r, with the same 55/45 ratio. I wouldn't go any stiffer than this! This is probably the balls-out racecar setup, and what I would get if I hop on this one. Rougher ride but less roll than the GCs.
I've also thought about going stiffer on springs up front, and pulling the front swaybar for more traction. But since I think I'm the only one trying to build a hardcore suspension with no LSD, I'm not going to bother doing the numbers.
A note on bias: generally you want the wheel rates to be equal f and r, but winning FWD race cars are usually 55/45 or even 50/50, even with a 60/40 or worse weight distribution. So while the 66/34 offered by the GCs and 7/3.5 and 9/5 setups is balanced F/R, it isn't the fastest way around an autocross course or track. However, that setup with an Aussie (or even 21mm BAT) puts it more towards 55/45, and is a good setup: I run it now and like it. Without an Aussie, I'd definetly run something like the 9/7 or 7/5 to get less understeer, and if you're looking for rotaion on the autocross course, an Aussie
and very stiff rear springs should help with rotation.
Sorry if this is confusing, speak up if you disagree or need something clarified.
