Silverton

When a shock is re-valved for a different spring rate, is the re-valving unique? By "unique" I mean that any two people at different locations will produce the same shock curve?

Also, is the re-valved shock curve (for a given spring rate) the same for for different shocks, for example, Bilstein versus Koni?

wtknght1

All those scenarios are possible, and I'm sure it does happen, but it's not common. And yep, it is possible for two different shocks to have the same curve...but again, it's not common.

It's kind of irrelevant though because each driver/car will end up with their own unique settings anyway.

gkmccready

I can guarantee that two shock guys will build different shocks for the same spring configuration. I can also say that even if you mimic a KONI curve perfectly with your Ohlins shocks they will behave differently dispite the curves being identical.

worldsaway

From my miata autocross experience it seems like shock valving is a "black art", like porting a head. I know there is the dyno to tell what the shock is set at, but it seems like it still comes down to somebody who knows telling you what to run. Is there really a science to it?

gkmccready

I think it's 99.9% experience with a particular shock, or brand of shock. Bruce@Performance Shock out at Infineon explained to me that he could valve an Ohlins to match the exact curve of a KONI on his dyno. But the shocks would behave completely differently when put on the car. *But* he's got experience with a bunch of brands and can look at the valving in the same KONI and, through black magic, come really close to translating that to an Ohlins.

If you're not using an off the shelf shock, and maybe even if you are, it seems beneficial to get friendly with your shock guy. Small explanations of how the car is behaving and what you dislike about it can get you some interesting comments... some times including changing an adjuster completely opposite to what you'd think, and some times with a comment like "sounds like the shock needs more bleed." At which point you smile and nod and say "how much?" :-)

BrianCunningham

depends on the shock as well

some brands require a 'fudge factor' since the same stack will produce different results.

Jahan

A dyno chart is only a VERY small snapshot of how a shock performs under certain lab conditions, and doesn't come close to fully describing the performance of the shock on the car.

A dyno plot is good to tell if your left and right shocks match, or to get a general comparison between one Koni valving and another. That said, I could build two Koni shocks that look identical on the dyno but feel completely different on the car.

The nuances of the valve structure and the pressure fluctuations within the 2 (or 3) chambers within the shock are what determine how the shock "feels." Those things are very difficult to quantify, even with a shock dyno.

I wouldn't go so far to say it's a black art, but experience means EVERYTHING when it comes to shock tuning.

There could also be significant variation from shock to shock, especially if they are built by different people.