Inexpensive shocks dyno'd...
 

Photo credits to JRZ/Novak Racing

https://sphotos-b.xx.fbcdn.net/hphot...20032418_n.jpg

https://sphotos-a.xx.fbcdn.net/hphot...81259139_n.jpg

Well, if those are all at the same settings the shock is putting out way different forces as it's cycled repeatedly.

On top of that, it looks like the output force is VERY dependent on position on the rebound side-not a good thing. Could be scaling though.

I'd like to see a force/velocity plot as well.

I *think* each line is 2-clicks of adjustment and it's run at 0-2 in/sec. Why that slow? because the slow speed is where a lot of important things happen. It's the range of speeds seen as a car brakes and turns in and accelerates out of a corner. To over simplify, low speed damping relates to grip and the high speed relates to ride, and this is why pretty much everything is digressive these days. Most dyno plots don't show really low speeds but it is very important, and the people at JRZ pay very close attention to what their stuff is doing in that range. It's also why there is such a huge step up in price to a 3-way shock because the way the valving works has to change pretty significantly and be made very precisely to only adjust low speed compression. When it comes to shaving down lap times however it's probably the most important knob. Anyway, I digress...

My take is that there is not very much low speed compression damping, there IS a good amount of crosstalk to the bump for a rebound adjustable only shock, it doesn't adjust very linearly if that's a word, rebound is slow to react and there is a weird slant to the curve (hysteresis I'm guessing).

That is only one corner so it would be useful to compare it to the others to see if they are all doing the same thing. I might be talking a little trash on facebook but there isn't really much you can take from that plot that says they are "bad," although there is nothing that says they are good either. I'm assuming (hoping) the noise and those kinks in the plots are just from the mounting or something.

Having seen many sweeps of JRZs run on that same dyno at the same speeds, the lines are much more clearly defined at each click, they generate full force with MUCH less displacement, and each line starts and ends at 0. And well that is all pretty important. If it takes a shock an inch of travel to generate the designed force it's not going to do you a lot of good. That's also why it would be good to see the other corners. Over a wider velocity spread they might all appear to be doing generally the same thing, but slowed down things might be very different. I found this to be the case on a set of shocks I had custom valved (and ran on that same dyno), and ended up sending them back. Turned out to be my fault because I gave the guy one damper from a different year and the oem valving had changed slightly. Regardless, the differences were very pronounced and I might not have noticed at a higher speed. And probably wouldn't have noticed driving the car for that matter.

all i see is a potato....

like jamal said, it would be nice to see it stacked up against another shock of the same model. i would also like to see multiple plots at the same setting but after changing the settings from different directions. i dont know too much about this stuff but i bet the repeatability is what the real money gets spent on.

Could someone explain this for us please!!!

That graph is showing hysteresis, dampening isn't optimal @ decel basically killing shocks recovery rate, and the rebound looks like its having a slight trouble at low speeds, nothing to be really worried about (other than you get what you paid for). But id revalve at that point.

Am i right?

https://www.facebook.com/photo.php?f...type=1&theater

Looks like possible an issue with the rubber mount used in the dyno for the rough readout?

The 500 series is an entry level coilover and a darn decent one for the money.

Not much better here... minus the smoothing

http://i26.photobucket.com/albums/c1...30tt/Dyno1.jpg

Fortune is waiting on their account to get approved. Can we get a mod to speed that process up?

PM Hachiroku.

Hello,
JB Autosports directed me to this thread. I work at Fortune Auto as a shock technician. The picture of our shock on the dyno and the football graph was initially posted on Novak racing's Facebook page last night. The picture was commented by Novak "Shock results. You get what you pay for. These things are a Pyle of sh@!"

I commented on the jagged looking dyno graph and after further inspection, I noticed that the shock was mounted to the dyno using the lower mounts rubber bushing. This bushing obviously has play and will skew the dyno reading of the shock.

You can view all of the comments from the FB page here:

https://www.facebook.com/photo.php?f...type=1&theater

To add to this, Novak racing was initially comparing an entry level FA 500 series shock to a JRZ shock. To those of you who are not familiar with JRZ, they are manufacturers of very high end race suspension. I think it is safe to say that they are at the pinnacle of shock absorber quality and technology. Depending on what model you get, JRZ's sell in the range of $5000-$14000. JRZ shocks are at the level of ALMS racing and beyond.

That being said, it is obvious that a $5000-$14000 shock absorber will outperform a $1200 shock absorber.

I noticed that some people made some comments about hysteresis, graph smoothing, and low speed shaft velocities and I would like to address those concerns. To get a bit more knowledge and insight about shock dynos, please read this: http://www.fortune-auto.com/shocktech.htm

Graph smoothing:
Under no circumstances are any of the graphs smoothed at Fortune Auto. I honestly do not even think that Roehrig has that ability in its software. This discussion came up on a evo forum a while back and we decided to make a video showing a dyno of a FA damper. Basically the video shows us mounting the shock to the dyno, conducting the dyno test, and the graph in its raw form.

Here is a link to the video
[ame="http://www.youtube.com/watch?feature=player_embedded&v=7jGSEakIOwU"]500 Series CVP Shock Dyno Test - YouTube[/ame]

To add to this here is a video of a 510 series shock on the dyno. PVP & CVP graphs, and then a comparison between a 500 series CVP to a 510 series CVP and PVP graphs.
[ame="http://www.youtube.com/watch?v=YENz6VbEdb0&list=UUu_6CszSIMyssYoyT-dUn9g&index=1"]510 Series PVP & CVP Shock Dyno Test - YouTube[/ame]

To compare apples to apples, I also included a CVP football style graph of a 500 series shock:
http://i26.photobucket.com/albums/c1...30tt/Dyno1.jpg

Hysteresis:

FA's new Gen 4 shock absorbers exhibit minimal hysteresis. I would like to point out that every single shock absorber will exhibit levels of hysteresis, even your $14000 JRZ shocks. Especially if the shock absorber is running a very digressive shim stack.

Hysteresis can be determined by conducting a CVP style dyno test. In the videos that I have posted, we conduct a CVP test and PVP test. Most shock manufacturers...let me rephrase that - ALL manufacturers publish PVP plots of their shocks. PVP plots are averaged and look better. Notice at the end of the first video how close the lines were together (minimal hysteresis) on the CVP graph of the 500 series shock that was just dynoed.

Here is a CVP dyno plot of a shock that is exhibiting unacceptable amounts of hysteresis:

http://www.fortune-auto.net/Shock%20...%20@%20250.jpg

and here is a CVP plot of our 500 series. As you can see hysteresis as at a minimum.
http://www.fortune-auto.com/fortune%...rees%20cvp.jpg

Low Speed shaft force:

Low speed force is common on linear style shocks. The more digressive a shock is, the more low speed force it will have. Anything below 2 inches per second on the graph is considered low speed and represents vehicle inputs such as roll, dive and pitch. A linear shock has very little low speed force, hence does not offer the same amount of vehicle control that a digressive shock would.

Here is a dyno plot of a linear shock. This is a $650 ebay set of coilovers:

http://www.fortune-auto.net/Shock%20...ow%20speed.jpg

Now on the other end of the spectrum, here are some VERY DIGRESSIVE Penske's that came off a World Challenge car:

You can see how exaggerated the low speed force is.
http://i26.photobucket.com/albums/c1...0tt/Dyno-1.jpg

Again your Motons, JRZ's and Penske's will have lots of low speed force. Here is a dyno plot of Motons off an American Iron race car (Photo credit Vorshlag)
http://i26.photobucket.com/albums/c1...nt-S197-X2.jpg

The 500 series does not exhibit the same amount of low speed force. Does that mean that its a crappy shock? Well of course not. It's mainly designed as a daily driver that sees occasional track use. We do offer more digressive curves that we call "Ultra Digressive" in the rest of our line up. Here is an example of the Fortune Auto 510 series shock graph. As you can see, it offers plenty of low speed force.

http://www.fortune-auto.net/510%20series%20gen2.png

The 2 graphs on the left are of our 2-Way Dreadnought shocks. Again, lots of low speed force

http://www.fortune-auto.com/Dreadnou...no%20Graph.jpg

Wouldn't you want to use the lower rubber mount as that's how it will act on the car? Just asking for clarity.

I forgot to address cross talk. When looking at the Novak racing dyno plot, you notice that the lines are extremely jagged. As previously stated the reason why this particular graph looks like this is because the shock was not mounted to the dyno in an ideal fashion.

If you look at the football graph I posted (which is very clear) you can see that there is cross talk but its very minimal. For a entry level coilover kit, I am pretty confident in saying that all brands will have the same level of cross talk or higher.

If you look at a JRZ, Moton or Penske sweep graph you will notice even less cross talk. These companies accomplish this by very high end machining tolerances of the their jetting assembly. This is one of the main aspects that separate a $1000-3000 shock from a $4000-$14000 set of coilovers.

Another thing to look at is damping adjustment accuracy.
In the realm of ALMS and professional racing teams, it is crucial to have a very linear damper force adjuster. You want each adjustment force to be equal to the next. On more entry level setups, the adjustment force is more progressive. This is not ideal for a professional race team, however its absolutely fine for your weekend and grassroots racers.