I recently got my shocks revalved by Proparts aka Tripoint Engineering. Today I received a set of dyno graphs of my shocks through fax and compared them to other graphs online of similar valving and found them to be different. It seems like my graphs do not have the low speed dampening and digressiveness of the other SPSS 3 graphs I have seen. It also seems like the magnitude of force is much greater than the other charts as the velocity increases. What do you "suspension gurus" make of it?

Mine:

Fronts


Rear


compared to slammed_93_hatch's charts:

Front


Rear


Notice when it is at 1 inch/sec, his graph is already at 300 lbs while mine is roughly around 150 lbs.

I thought it be fun to do a comparison so I made a chart through excel as accurate to the best of my ability:







Modified by Andrew 825SM at 7:54 PM 2/27/2005

 

my guess is that its because your were valved at tripoint and mine were done my koni.


Lee has said that the SPPS3 is just what they call it, and not every one that does there shocks does it 100% the same.

Now what does this difference mean? i have no clue

 

Is it just me, or do your graphs appear to be upside down (not literally, but the valving is the "flip" of the other graphs).

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Crack Monkey &raquo;</TD></TR><TR><TD CLASS="quote">Is it just me, or do your graphs appear to be upside down (not literally, but the valving is the "flip" of the other graphs).</TD></TR></TABLE>
Exactly what I was thinking...

Maybe Proparts inverted their numbers somehow?

 

Different shock synos have different output formats (similar to engine dynos). The rebound is the one with the larger magnitude regardless of whether the force is negative or positive. If not, then you have a problem.

Also, my experience with revalving smaller shocks is that changing the shape of the curve (digressiveness) is easy to do with small changes to the washers etc., but reducing/increasing the force by a significant margin requires different hardware (ie. piston, needle).

Does the SPSS valving require a different piston? That would make a big change between the two.

 

Added some graphs.

 

I was out of town the end of last week and unable to respond. I would like to check a few things with Pro-Parts primarily regarding their dyno sample speed settings as that has a lot to do with it. The dyno takes measurements at any of a number of piston speeds that you can set and then connects them with the lines. If theirs is set very different for ours or another dyno then it could look different as well. The thinks like theirs having rebound on the bottom (we do it on the top), being in inches/sec. (we use fractional meters/sec.) and pounds of force (we use Newtons) is all simply a matter of preference for your dyno settings. You get used to one style of setting and then others seem odd to you even if it is the same data presented differently.

The Pro-Parts folks will be visiting us for a few days this week so we will discuss this.

 

just curious. was this ever resolved?

 

Yes, all is well. The issues were not really issues, just mostly differences in dyno settings mostly as to where data collections points are and that one graph was measuring peak force and the other was measuring and averaging continuous force. At extremely low speeds this will often get somewhat different readings. It has been confirmed that he has the SPSS3 valving that he wanted and all it well.