Spring Rates...going stiffer

[atombmb]

My UK Atom 2 has the standard Bilstein single adjustable shocks and these springs:

Standard Springs:
Front : Assister 40-60-20, Main 180-60-40
Rear  : Assister 40-60-30, Main 180-60-50

I'd like to try going stiffer as the car is mostly used for track events and the spring are pretty soft.  Anyone experiment with higher spring rate springs?

[MonsieurX]

i just set my dampers from position 3 to 2 for damping rate. That's damping and rebound combine if m not mistaken. In a race track where i've driven more than one day on the 3rd setting. Damping rates are usually logarithmic like.

Harder springs on the BMW Z3 made sense. And you felt a difference. The damping rate however, you really didn't feel much because of the weight. On the Atom, the size of yur passenger matters... So stiffer springs and damping are much more noticeable - which i indeed noticed!

The car is DEFINITELY a harder ride and no longer comfortable (can't wait to try #1)! High speed turns become less playful, more precise, less forgiving and not just more G stressing but also more twitchy... Also your turning ability is reduced somewhat in lower speeds corners or slaloms... With stiffer springs, you will have a faster acceleration a little, somewhat better braking (though in the atom without ABS that's probably hard to rate - i'd say worse).

Worst of it all, with also a lot more bouncing of the rear wheels for short amplitude bumps... Landing while on the throttle can have some interesting results... Imagine what that can do on your front tire when braking

Just my 2 cents, correct if im wrong... kind of written in a hurry... 
That's dangerous on the atom...

[Heywood-Yablowme]

Don't forget to play with tire pressures a bit as you raise your spring rates. I dropped mine a few pounds and it made for a better feel. Not dramatic,but better.Also,your suspension alignment becomes much more critical as you remove travel from the suspension.. less forgiving,like you have noticed.Be carefull not to dial in too much rebound dampening or you will get a skating effect over bumps.Try more and less camber for a better feel as well.Toe in does not seem to make much difference once you find where your car feels comfortable for you.Keep a log and don't be afraid to try other settings.More is not always better when it comes to camber. I am amazed at how well my car responds compared to stock.  

[atombmb]

So what camber are you running?  What tires? Pressures? My issue is that once I get back on the throttle mid corner the rear suspension compresses too much then let's go, I catch it but the drive out of the corner is ruined. it happens on every corner except a few that are banked.  I'm hoping that the stiffer springs wont let the rear compress so much...who knows.  Just keep trying stuff.

[Heywood-Yablowme]

The stiffer springs will def help with a mid corner power transition issue.They will not allow the rear of the car to squat,which will tend to unload the tires.Think of it as eliminating wheel hop,only mid turn.Make sure you adjust your rebound settings for the heavier springs.  Try 1.5 negative all around as a starting point and adjust up or down to your liking.I am running wide Formula Atlantic Hoosiers;very sticky. They like a bit more camber ,at about 2 negative is nice for me.They may grip better at 3,but I don't like how the car feels down the straightaways with 3 degrees all around.(a bit twitchy)
Tire pressures will be something you adjust based on your driving and tires.I found I am a few pounds lighter with the stiff springs. I am running 300lbs/inch in front and 500lbs/inch in the rear. Stiff, but not a bad ride at all.

[atombmb]

I am 2.5 in the front and 1.5 in the rear and am just about to head to the track with new springs in these flavors. 
50 N/mm = 286 lbs/in
60 N/mm = 343 lbs/in
Running A6 tires.

Thanks for the learnings.

[Heywood-Yablowme]

  Much luck! Don't forget to take notes.