Thread: P10 springs

I have been contemplating on replacing my springs on my P10 and am kind of stuck on what to go with.

My setup:
AMR coilovers with 8K front and 5K rear springs now
Addco rear sway bar
Stock front sway bar
Front shocks on full soft
Rear shocks on full stiff
I am not happy with the handling if I have any other shock adjustment, even 1 level up in the front makes it push even more in the front. I need to be on the gas in a corner otherwise it feels like the front just digs in. I was thinking of going 8K front and 8K rear. This would let me adjust to taste with the shocks rather than using them to correct an improper setup. I like how the car has minimal body roll now but I would like a little more rotation in the rear. Also the car does get a little bouncy on the interstate, basically at times it seems like there are whoop sections where the frequency is just right to match the wheelbase of the car. Not sure if this is a shock setting issue, too much preload, or just a side effect of stiff springs.

So, questions...
Is anyone running an 8K front and 8K rear setup? Too aggressive?
Would I be better off with 7K front and 7K rear? Might be a slightly better ride, but will I loose some overall handling capabilities?
Or some other combination?

let me look up what we have but what I can tell you is that we have a stock front sway bar and its VERY loosely attached (as in with worn out mounts to make it do almost nothing because per letter of the race rules, its all stock and there and is legal) but we go full stiff front and rear for track use and full soft for street use or rain races... pretty sure we have the same 6k/8k setup but lemme see if I can find out for sure. ....we also have stock rear sway bar as an FYI and have considered going with stiffer rear springs to get the back to rotate more FWIW.

Waiting for the hubby to confirm but pretty sure we have 10k front, 6k rear as of this moment

CONFIRMED: We have 10k front, 6k Rear as of this exact moment

How much does your car weigh? Has it ever been corner balanced? What are your alignment settings, front and rear? What tires are you running, size and model?

Our car is driven on the street with the shocks turned all the way down and it is not bad at all. Having the rear on full stiff on the street is going to cause a very harsh ride in the rear.

Got an alignment sheet so I can see your chassis setup now?

I don't think I have an alignment sheet, but it was suppose to be set to 0 toe front and rear, -1.75* camber in front and -1* in the rear. front caster I am not sure on.
The last time I weighed the car it was ~2550 lbs with no driver. I have never corner balanced it, but something I could do. I am running a Kumho Ecsta AST tires in a 205-50-R16, they are 3-4 years old now, still quite a bit of tread left.

I jacked up the car yesterday to look at the rear springs and verify that they were 5K, when I jacked it up the tire dropped a whole lot more than I expected, the spring had no preload. I know I set these up, when I built the car, with 3 full turns of preload as AMR suggested. So the springs must have settled, not sure if this would make much of a difference or not.

Caster and thrust angle if you please?

I am developing an answer as we go. Thanks, Nick.

I cannot find an alignment sheet, not sure if I even got one. I did ride home the other night with the car on full soft and it rode much better, better than I remember. There was quite a bit more body roll as well that I could feel in the rear. It seemed to have better low speed cornering as well, but without driving it more I am not sure. It is supposed to be warm the next few days so it will sit until it cools down again. And it needs an oil change.

It sounds like there is something wrong with the rear springs if they settled that much. We have put about 30k hard miles on our AMR suspension and have not seen this issue. If you want more rear end rotation, I would recommend increasing the rear spring rate, but your current grip is most likely limited by your tires. Our car weighs about 2760lbs with driver, with stock sway bars and the 10k/6k set up the rear rotates nicely when driven aggressively on R compound tires. Getting the car on scales might help if your cross weights are way off. If your corner balance is way off, the car might work better turning one direction versus the other.

The springs were the cheapo's that were used during the group buy, Andy at AMR even said that the Hyperco springs were way better than these. After driving it at full soft it rides a whole lot better and does handle better low speed and high speed. I know I have tried this in the past and it did not do well, thats how I ended up at full stiff in the rear. Who knows though, I could have been imagining things. I think I will order some Swift or Hyperco springs, whatever AMR is using now, in 8K/6K just to firm up the rear slightly. I do not need to go crazy and still want a somewhat comfortable ride.

Thanks everyone for the input.