Hi, I have a problem with my car's suspension.

The car is a 97 Civic hatch with OTS Koni Sports and GC sleeves, default spring rates (350 lb/in in front, 250 in rear). Anti-roll bars are 21 mm in front, 15 mm in rear.

The problem manifests itself in the rear end.

If I turn the shocks' ***** to soft, the highway ride is good (good high frequency damping), but in large dips/bumps the car is very floaty, the suspension cycling twice before settling (underdamped low frequencies).

If I harden the shocks, the car responds well to large dips but becomes overdamped at high frequencies, the rear end skipping all over the place at normal highway speeds (50-70 mph).

I tried to find a balance between these two situations, but couldn't.

Did anyone else experience the same thing or am I just being too picky for the price point?

 

Define "default" spring rates. What are the actual rates (found on the springs)? Turn the **** all the way to soft and work your way up from there. Without driving the car it's hard to say what setting you will feel comfortable with.

 

this is inherent in the lack of compression damping in OTS koni's.

you seem to have a feel and technical experience enough to actually get a feel of the koni's, judging by your differentiating between high and low speed damping characteristics. much better than these yahoos who gloat over their shiny new toys like chicks and prada bags.

when you turn the **** all the way, youre feeling the shocks actually jack down. the shock compresses more than it should because of the lack of compression damping and the rate of return is not fast enough to recover because of the huge amount of rebound damping limiting the return speed. hit another cycle and it compresses the spring even more.

when the **** is set low, then you just have an all around low damping force. so of course its floaty and can soak up the bumps.

if you cant find a happy balance to your liking, theres two things you could do:

1) increase the spring rate. it covers over the lack of compression damping. a lot of these ppl who get 400-600 lb springs dont realize the effects as much because the spring is limiting the movement more than say stock 380/280 springs would. you can up your front springs without much affect to ride quality. and leave the rears soft, and soft rebound but up the rear sway bar stiffness for turns.

2) get them revalved. people who prosyletize (and blindly believe) the wonders of koni because they are used on top winning "racecarrrrss" dont realize they are custom valved. its no secret the main reason is to increase the compression damping, and even add extra compression adjustment, whenever its legal.

actually there is of course a 3rd choice... ditch em.

 

Thank you for the insight Tyson, that explanation makes total sense to me.
Do you know whether the famous SPSS3 valving provides a useful increase in compression? I wish I could find a force-velocity plot for it, all I found was force-displacement.

Friends with other make cars speak highly of Bilstein Sport shocks, but information regarding Honda applications is scarce and the few opinions I found here said they're overdamped in Honda applications.

Hi, I've completed the information in my first post as per your suggestion.
The problem is that there is no good adjustment, I've fiddled with it no end.

I currently have the rear shocks at 25% stiff, which is the hardest I can tolerate regarding highway ride but is still way underdamped in large dips/bumps.

Thanks again everyone.