Fantastic. I wrote this thread off but you came back and followed up. Eagerly awaiting the results!

 

Subscribing

 

Performance Shock has our DTP system in their possession. Bruce have been very helpful with this whole process. We will post up the specs once sent back to us.

Alex

 

bump

 

This is one long dyno test.

 

Reading ftw

 

 

Sorry, Ark fans.

 

no need to be sorry. Let me also add that PERFORMANCE SHOCK is an awesome company that will
make any suspension enthusiast feel at home. Very knowledgeable in this area of tuning. We will be working with
them in the future for our time attack 350z and our future products.

This is from out 350z STP damper kit. If you have any questions please do not hesitate to ask.

Alex

 

*waiting for Gsedan35 to explain what all of the above means*

 

one of the reasons why a lot of the companies do not provide consumers with graphs. In any case, we have our dynos up. All raw images, nothing has been touched. Now for other brands to contribute....

 

So, was it the DTP or STP?

 

Me Too!

But a big UPS to ARK for doing what I've seen no other suspension vendor do, actually test their product through an unbiased third party AND post the results.

Looking forward to the analysis...

 

From what I see the shocks are extremely progressive at low settings and only become linear at the highest setting. There is no digressive valving and no "knee" below 2in/sec. Compression also increases slightly as you go to a higher setting. An optimal single adjustable shock will only effect rebound and not have an effect on compression. Not a curve for track use but hey, I'm not a professional by any means.

Generalized, short, and simple explanation: Performance shocks will usually always have digressive valving. This means the shock ramps up lots of force before 2in/sec. After 2 in/sec the slope of force/velocity will decrease. Reasoning behind this is that cornering loads happen at a rate before 2in/sec so you want a lot of rebound. Any force that occurs at a higher rate than 2in/sec is from surface irregularities and you want less rebound so the wheels stay in contact with the road.

For example:


OTS Koni Yellows offer a digressive valving (although only at higher settings which is common with almost all OTS street shocks)

Another example (buddyclub):

 

These are the STP's.

 

Is this what you mean by this statement? Im trying to understand these results... :

 

In this image, the rebound doesn't adjust to any practical level, it is the compression forces which see the change in damper settings. The lines on the top half of the graph are compression (positive values) and the lines on the bottom half are rebound (negative values). You can see the rebound settings practically overlap one another in this graph, while the compression changes with each step of the adjuster.

Remember, compression corresponds to the damper's motion under bump travel, while rebound is the extension of the damper due to the spring's energy.

I also prefer my single adjustable dampers to adjust the rebound, especially within the low-speed portion of the damper's range since those are the speeds at which most transient motions occur.

Will

 

That graph is showing changes in rebound. Rebound isn't always a negative force on graphs, whoever performs the shock dyno will dictate this. You can figure out which one is rebound because rebound will always create more force than compression because you need the shocks to damper the springs to prevent oscillation. Too much compression will not let the suspension conform with road imperfections.

 

Figures. I hesitated in writing this because I have never seen a damper with a compression force like that, and my first thought was that it looks like a rebound curve going from progressive to digressive, but I have also always seen our plots with compression as positive values. My mistake, and sorry for adding confusion GeauxLadyZ.

So, to clear that up for you GeauxLadyZ, the graph you posted shows a damper where rebound is altered but compression is not. What's interesting to note in the Buddy Club plot is the slope of the rebound force up to about 50 mm/sec (low speed) changes the damping curve with each adjustment from progressive to linear and then to digressive.

Will

 

Yes, the closer the lines the less compression forces change with each shock setting. Sometimes shocks are designed to increase compression force with rebound at the same time (Tokiko does this). Its their tuning philosophy but everyone has their own beliefs.

Regarding your second question, I just want to clarify that shock forces respond to shaft velocity (Velocity determines shock force. Shock force does not determine velocity). So, as velocity increases, shock forces will increase.

I'll try digging up a race valved koni graph or similar to show what an optimal shock dyno looks like so you can compare differences.