DamonB

All that does is tell you there is gas pressure inside the shock. Shocks are velocity sensitive devices; their resistance to a particular input rises in proportion with the velocity of that input. If the velocity is little, their resistance is little. Trying different shocks on the car or putting them on a dyno is the only way to judge them.

jgrewe

iTrader: (1)

V8Mongrel, When a shock a chosen or revalved for a specific application the shock person will just need to know some info about your car. When they have all the info they just do a little math and then pick whatever valves do the trick in their shock.

They will ask for sprung weight, unsprung weight, ratio of movement from the shock to the wheel, spring rate and maybe even the type of bushings you are using. Form that info they can figure out the critical damping value and valve for that.

You will much better off having a set revalved for you than pulling something for another car off the shelf. The other car may be heavier sprung or have heavier unsprung parts. Either of those situations will hurt your set-up, shocks for a car that is heavier sprung will hurt your rebound response and unprung differences will show up in compression. Then, if that doesn't mess you up enough what if the velocity ratios are different or your springs are stiffer than the heavier car.... You can save yourself a ton of "what ifs" having the shocks done for you by some one who knows the shocks characteristics on a dyno.

The only thing you won't be able to do is make the little low speed adjustments in valving at the track to tune the car for different corner entries or exits or transitions in esses but then that starts to cost $1000-$2500 a shock.

V8Mongrel

I had an excellent discussion with Steven Ellis of the aforementioned Ellis Engineering about valving dampers. He really like Bilsteins, citing their excellent materials and production quality. However, he has difficulty revalving them for race use because the low speed bleed and valving is controlled by piston holes, not by washer stacks that are adjustable. Thus, you are either limited to the factory valving or you are going to have replace the piston, which is expensive.

Of course, low shaft speed is where the dampers do the most work from a handling perspective, so this is a limitation that is quite serious if you are considering revalving production Bilsteins for race use. I didn't get specifics on whether this is all Bilstein units or if the range is acceptable for some uses, so please don't take away that a revalved Bilstein cannot work. It is just the perspective of someone who is inside shocks every day and something I neither knew nor had seen mentioned before.