All true but you're forgetting that the target audience for Teins, especially the CS series, aren't going to be die hard track junkies. They want to lower for looks and get some adjustability. Many will set it and forget it.

Those aforementioned track junkies will be looking at Ohlins or Motons (for something other than the IS, for that matter.)

 

True, lap times don't lie, but how consistent are your lap times over a session, and how much control do you have over everything else? If you really want to tune your double, triple, or quad-adjustable shocks for maximum performance, you need to know what your damping curves look like. This means at least having access to a shock dyno, or buying them from a company that will furnish plots for you.

 

You have to be practical if it's a street driven machine. Tuning to a gnat's eyebrow is great at the track where it makes a difference you can measure on the watch. On the street, if you are off two clicks, you may not even notice unless you are driving WAY too fast for the street environment. The fundamental problem is getting good compliance with settings that don't pummel your kidneys or make you feel the car is doing things to make you nervous. The good compliance part is where most boy-racers get it all jacked around. They equate a super-stiff ride with high performance, when nothing could be worse for street driving.

Lowering the car invariably means either you increase roll, or you need stiffer springs to counter the roll increase. Stiffer springs need stiffer dampers. Stiffer dampers and springs mean your compliance over things like stutter bumps or washboards (very common on the street) will be poor. So, both accelerating and braking will suffer, and we haven't even tried to drive around a turn with a few bumps yet. You can try to band aid it with stiffer sways, but then you lose the independence in the suspension, and we're right back to that wheel compliance problem again. Add an adjustable shock that really is only nominally adjustable, and there's the salt in the wound.

I wouldn't go on and on about this issue, but I've experienced these problems. I've hit the brakes on a washboard surface with a really stiff suspension and ABS. I nearly went completely through the intersection I was trying to stop for because the wheels were only bouncing off the tops of the bumps, and the ABS was fighting me for control - I was losing the fight pretty badly. I would have much preferred locking the wheels to what was actually happening.

So there you have it. Sure, it'd be great to have all the engineering info on the shocks to tune them, but in service, all that stuff is academic. Either it works, or you adjust it until it does, or you take it off the car because it doesn't work.

 

There are quite a bit of misinformation going on in this thread. Instead of quoting it line by line, I will just try to clarify it in one post. People, please don't take it personal if I called out what you said as wrong. Just try to deliver the right info.....

Camber won't kill tires, toe will. As you lowered the car, tires gain camber and toe. It's the dynamic geometry of double-wishbone/multilink suspension. Whenever you modify the suspension that affects ride height, you MUST re-do the aligment to set the toe back within spec.

The negative camber is ok, as a matter of fact, you NEED more negative camber when stiffer than OEM springs are used; because with stiffer springs, you loose the dynamic camber gain as the wheel compresses (stiffer springs = less wheel compression = less camber gain). As long as the toes are set straight, tire wear would not be an issue for about -2 of camber.

Single adjustment for both bound and rebound on aftermarket dampers is not a bad thing at all. Sure double/triple adjustments are better, but it's not for everyone unless you have extensive time to tune the suspension for a specific driver on track. For everyday usage, single adjustment is more than enough. Actually many race winning dampers are single adjustment only (mostly Group N), so it's really nothing wrong with that.

Ride height only has very minimal effect on body roll, meaning that raising or lowering will not noticeably increase or decrease body roll. For double-wishbone/multilink suspension, roll center and ride height change at a close to 1:1 ratio. So you will end up with the same amount of roll when you lower (or raise) the car. However, you still need stiffer springs after lowering because you don't want to bottom out the dampers.

Suspension tuning is a matter of manipulating the load distribution during cornering, while keeping stability in braking and acceleration. It's a compromise among all aspects. I don't want to go into too much detail, or it will be pages long. However, stiffer springs are the necessary evil for better handling, you can't deny that. In order to increase cornering grip, ride height needs to be lowered and track width needs to be increased. These 2 are the primary elements that dictate weight transfer. By lowering the car, you need stiffer springs to keep away from bump stop. By widening the track width thru low-offset wheels or spacers, it retards the motion ratio, making the springs less effective which also drives the spring rates up. All in the expense of everyday drive comfort.

With 6K-8K (or even 10K) of springs on a quality shock, the tires should have no problem staying in contact with the pavement even with normal irregularities. Just don't "slam" the car and keep the toe setting within spec, your car will love you, your passenger will love you, and you will be one happy man!