Koni FSD Shocks

[SoSideways]

OK, so basically it's just a digressive valving.

[racepar1]

Originally Posted by SoSideways

OK, so basically it's just a digressive valving.

I believe that the pretty much all koni's have digressive valving. As far as I can tell these are supposed to kind of auto adjust dampening as you drive. They would be good for a street car, but if you really wanna track your car you want to be able to adjust the shock yourself.

[aznpoopy]

explained simply, the system comprises an extra flow passage (besides the normal one) and some kind of valve/diaphragm that controls the passage.

when you hit a hard bump, the fast compression of the shock makes the liquid inside move fast. the diaphragm responds to fast flow slowly, so the extra flow passage stays open. that makes the shock softer.

when you brake/corner/etc., the slow compression of the shock causes the liquid inside to move slowly. the slow movement of liquid causes the diaphragm to respond rapidly, closing off the extra passage. this makes the shock harder.

what does this mean in real terms?

Originally Posted by SoSideways

OK, so basically it's just a digressive valving.

not at all. imagine your typical adjustable shock with a hard setting and a soft setting. if you can picture it on a dyno that means there will be two lines represented, one for hard and one for soft.

if it were merely a digressive shock you'd simply have two digressive paths traced out, but no way to alternate from one to another on the fly (minus something like an EDFC), and no way to utilize the settings in between those two lines.

Originally Posted by racepar1

As far as I can tell these are supposed to kind of auto adjust dampening as you drive.

i believe this is correct.

now take a FSD shock... it can have the same range of damping as the old style 2 click shock described above. but it has the ability to utilize the entire range between the old hard and soft settings depending on how fast the shock is moving. that's analogous to a traditional shock with an infinite number of clicks within the set damping range, with the shock automatically setting itself to the appropriate click for the situation based on frequency of oscillation.

you can see this at the end of the application (and in FIG. 5 of the drawings).