heel_touge

so i picked up some zeal S6's from a user on here. they didn't appear to be blown in any way in fact they looked to be in great condition. the spring rates on it are 384lb in front and 450 in the rear. Im not used to this rear biased setup but the car is bouncing all over the place. is the oscilation synonamous with the rear biased setup? could it be because these dampers were valved for heavier springs so the low speed bump is not in sync? i would like to figure this out but learn some more in the process. so im not looking for "sell them and get something else." i want to know WHY they do what they're doing so hit me up with some tech!!

6spdKEG

I think you may have gotten your hands on a setup that has been altered.

I think most of the Zeal Function S6 packages come with much heavier spring rates. over 550#s front and rear and typicall with the heavier spring up front but they can come custom valved.

I've heard that sometimes the frequencies produced by the front and rear do not like eachother and can cause a PO-GO effect with the car which kinda can be what you are describing. I'm not sure of the spread on rates, but I don't think you have anything to worry about with your rates.. .

Try to go with 450 front and the 380s rear.

If you want to stay with lowish rates - order 550s or 600s for rear and put the 450s front and see what happens.. .

heel_touge

they definately were not the stock rates for the setup. i was aware of that, but i wasn't sure that would be the cause. so at this point its a matter of finding the correct rates to more closely match the stock valving of the damper?

6spdKEG

I'd shoot for what the Basic S6 model comes with for the car you have.. .

Do some research to find what it is.. .

Andrie Hartanto

I'm willing to bet you are riding on the bump stops.

Most Japanese shocks are really short. They usually come with pretty high spring rate and you have to preload them.

Assuming, this is a street car. Your front corner probably weigh 800 lbs. At static position the springs are compressed about 2.1" just by the weight of the vehicle alone. If you don't put a significant preload, the shock is compressed by 2.1". In most short japanese shock, you are probably riding on the bump stop.

heel_touge

they are preloaded. well, the spring has no play; i only use the cups for height adjustment.
but i get what your saying, basically the rates arent heavy enough for the valving.?

Andrie Hartanto

It has nothing to do with the valving!

Unless you preload it by about 2" the preload you did done nothing!

SleeperGSR

normally in a front drive car you want a higher spring rate up front, as that is where all the weight of the car is. I would try to get a higher spring rate in the front than the back. If you want a rear bias car, you can stiffen it up with bars and tire pressure. You should be able to get sufficient oversteer with that.