trinis2001

There is a lot of stuff around on "which coilover", "this rate is too hard" etc. The info is spread out all over a million threads. Is it possible that we get a CO setup thread started? I did some searches and its hard to pull it all together without getting lost in the traffic.

I would like to know for instance, how to correct a particular "feature" or what causes such and such.

Now that I have my set in at 12KF,10KR, the ride is surprisingly smooth which seems to fly in the face of the warnings from those who say these standard JDM springs rates are too hard. Maybe it was not harshness being referred to, but other aspects such as:

Ride:
1. The ride though smooth over bumps and undulations, now seems jittery - that is to say. it seems to be following all the unevenness of the roads rather than absorbing them.

2. Is this because of the heavy springs or can this be dialed out with the adjustable dampers?

3. If this can be dialed out, which way, harder or softer?

4. What are the general goals when looking for the correct setup with adjustable dampers for:
(a) on road ride comfort
(b) on track all out handling performance

Adjustments
1. What is the effect of too soft on the dampers? Softer ride but the springs do their stuff unchecked?

2. What is the effect of too hard? Stiff ride and no give so a dangerous setup on anything but the smoothest of (race track) surfaces?

3. What are the expected benefits of corner weighting - neutral handling?

Assuming only through damper settings:

4. If you wanted to correct oversteer - can this be done by simply softening up the back and vice versa to induce it?

5. If you want to correct understeer - soften up the front and vice versa to induce it?

Comple mentary
1. Especially for the older cars, do you get much from just CO's or must you add other things like shaft spacers, bump steer correctors etc etc, given a stock or near stock ride height (less than 1" drop - two tight fingers between tyre and fender rather than two free fingers and some ).

2. And whatever else I am not thinking about because I just don't know was they pertain to COs and handling.

Goals
1. I am in it for handling improvement and not looks for lowering etc. Need stock ride height for the kind of roads and obstacles we have here.

Dembo

The Bilsteins were something like 5Kg/mm which seems hard enough. You certainly know about the big bumps.

Remember that the suspension's main job is to keep the wheels on the ground. I've found with mine that on some roads, especially where there's continual rough stuff setting the dampers harder can feel like a nicer ride. That's because the suspension can't react fast enough and you're essentially flying through the air. And when a wheel is in the air it has no grip at all.

Setting it softer and it works and you have more grip, but as you describe it tends to follow all the little undulations of the road and can feel a bit jittery. I think the Bilsteins go too soft: on the softest setting it feels very sloppy, and I always have them set a bit firmer even for the road.

I was told by Andy Walsh once the way to setup dampers is to start soft and drive round in circles to see how fast you can manage before starting to lose grip. Keep making the dampers harder, which will improve things up to a point where it will start getting worse again. And then you've found your ideal point - for that road surface anyway.

All a compromise of course. At the Nurburgring there's a really bumpy bit on the entrance to Hatzenbach and I've found with the dampers set softer I can get through there fairly quickly, but the car feels less sharp and I lose time everywhere else. Dampers set hard and it's better for most of the 13 miles, but it tries to kill me on the entrance to Hatzenbach.

As I understand it, which ever end of the car rolls the least has the least grip (i.e. stiffer rear anti-roll bar means oversteer). The dampers don't control the amount of roll, but they do control the rate of roll. When you're in the middle of a long corner, the dampers are having no effect on the amount of roll,and no effect on understeer and oversteer, but they do effect what happens on the way in, and on the way out.

What I do on track is set the rears on the firmest setting, and the front slightly softer. This means the front will roll quicker than the rear. On the way into the corner the front is rolling more than the rear, so you get more oversteer. On the way out, the car is now rolling back, but as the front changes quicker the front now has the least roll and so less grip. Entry oversteer (i.e. better turn in), and exit understeer (i.e. more rear grip for getting the power down). It really does work.

Do it the other way around (stiffer at the front), and you'll have horrible turn in understeer, and a car that will try to kill you as soon as you go near the throttle on exit.

I only have the one setting on the Bilsteins; maybe the Nitron boys can tell us all about having seperate low speed compression, high speed compression and rebound.

I don't claim to be an expert, but I do like having things to adjust and then go out and see what they do.

trinis2001

Sounds good to me Dembo. I am going to try your technique to of softer front and stiffer rear. I would have done it the other way around and wondered what the heck was going on

One thing

Why does the front changing quicker = front has less roll? It is going through the same roll it went through on corner entry to right itself when coming out. Is it because it gets back to neural attitude quicker than the rear, so while the rear is still coming out of it (still rolling back) the front is done so it "appears" to have less roll relative to the rear?

m1bjr

Anyone thought about taking off the front ARB completely then?

trinis2001

Won't that give the front plenty of "stick to it-iveness" and cause even more oversteer?

Ultra_Nexus

I suppose if you upped the spring rates, you could bin it.

Paper Lawyer

I guess I should contribute.


I think you meant, "Complementary".

HTH.

Dembo

Yep. All a bit hard to get your head around.

Dembo

In theory you'd have terrible oversteer, but I'd bet you'd actually end up with terrible understeer. The reason being the front would roll so much you'd exceed the camber on the front tyres and you'd be killing the outside edges, whereas the rear would still have a decent amount of grip.

trinis2001

Tonight I tried the dampers on full soft then full hard. Full soft is as expected, real good for the small ripples and sharp bumps/drops, horrible for those larger "sinks" or "bumps" at speed; the springs just have their way.

At full hard, I see no reason why I should not just leave them at this setting. The expected harshness never showed itself. Even at speed, the large sinks or bumps are handled well, but I can see how it may get testing at low speeds on a washboard like surface or with lots of ripples. And this could be dangerous in a corner at speed. But lordy - the knife edge response seems worth it. It's all new, so it seems livable for now, but maybe after a couple of weeks on the B roads, I may not feel so warm about these hardest settings.

Dembo, coming back to the rate of roll as controlled by the dampers, how are your tack settings affected (if at all) by different spring rates front and rear? If the fronts are stiffer (12k vs 10k) then they should resist roll more than the rears for longer? So the front dampers would need to be set way softer than the rears to get the effect you described you think?