WTF is a Shock Dyno??

[Highrev1]

KONI Civic presentation slide 1
Stolen from \/\/\/
Honda-Tech.com: Suspension: [FAQ] Shock Dynos


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Koni




"The different speeds in which a damper performs deals with different aspects of handling and ride quality.

Low speed Valving deals primairly with Handling, as it influences how quickly weight gets transfered around the chassis.

High speed Valving deals primairly with how the shock reacts to impacts, such as bumps and ruts....

Mid speed Valving deals a bit with both.

then you get in to Bump Valvling Vs Rebound Valving.

Bump Primiaily deals with ride quality.

Rebound Primaily deals with handling."

THese are just some dyno's and what not but you get the general idea I hope. Basically the dampers are the most important part of your suspension and without a truly high quality



"I'll do my best to give a brief explanation of how to read shock dynos. This is a topic that could go on for pages and pages, I'll lay down the basics so atleast you know what your looking at.

That shock dyno is not a very accurate dyno. You want dynos that relate shaft speed to force. Such as this

http://www.roehrigengineering.com/im...ogrph2quad.gif
Dynos looking like this are generally PVP, peak velocity pickoff. These tests run the shock at various peak shaft velocities. They are not continuous, discrete velocities are recorded, ie 5 m/s, 10m/s, 15 m/s, 25 m/s, ect. The force the shock exerts on dyno is then recorded, and plotted on a graph. A line is then drawn to connect the dots. This gives you a easily readable graph that can relate shaft speed (velocity at which the wheel is going up or down) and how much force the shock obsorbs from the spring. These are not very accurate though because only discrete velocities are recorded. These graphs are a good indicator of overall shock performance though, you can look at the shape of the curve and decide if its right for your application. These are the most common by far.

Anything less than 5 m/s is considered micro movements, this is movement mostly by body roll. Anything above 5 m/s is shock movement from bumps and dips in the road.

Now read this KONI Civic presentation slide 1

That is all a PVP plot. The next type is a CVP, or continuous velocity plot. This records a complete cycle of the dyno taken. There is no longer a "connect the dots". It looks like this
http://www.roehrigengineering.com/im...ographfull.gif

This shows you force in compression and rebound, actually it shows it to you twice. If you can picture the bottom end of the shock rotating on the outside of a pulley taht is being rotated, and the top end being fixed, you will see that with one full rotation of the pulley you will experience compression and rebound twice. This is more accurate that a PVP, but harder to read. The most important thing to pick up from this is the area inbetween the s curves. This is called hysterisis. This happens everytime you hit a bump and the suspension settles (up down up down). The hysterisis is caused by cavitation inside the shock. The more hysterisis the worse as the shocks ability to dampen the force is taken a way.

How to read curves:
Linear - very basic. Generally you want this on your rebound force. Springs are a linear force so you want a linear force to control the energy stored in a spring as it is being released from compressed. If you have a linear compression you will have too high damping with high shock speeds which will give a harsh ride and make the car feel unstable with mid speed bumps.

Digressive - Generally this is what you want for compression. You want high low speed damping to control body movement, but then as velocity increases the rate at which force increases decreases. This allows for bumps to be absorbed well and gives a better ride.

Progressive - Generally not what you want. I would imagine this is good for some type of racing, maybe dirt track racing?

"

[Yodums]

I'd rep you if I can. Once again, you always provide valid statements behind your theories. Now I have a thorough explanation of why you push a good set of dampers so much.

[Highrev1]

Thanks I try I started out on the street made my mistakes and then surrounded myself with people who acutally know WTF they were doing that is when things started to click and make sense as to why one thing works and somthing else doesn't. Alot of this stuff is cold hard facts not just a "feeling" and that is where alot of the members are missing out.

[sickyute]

half those members couldn't care less ... but the more u pump it out, the more likely they are to see the light

[Izzy]

Subscribed!

[LucasBlack]

+1 rep to highrev1 :)

[LucasBlack]

can someone please sticky this thread before it disappears off the face of the first page....

[Mitch]

+rep. It's good to see REAL information on the forums, and not just people sharing their gut instincts on how things work.

[Highrev1]

Originally Posted by LucasBlack

can someone please sticky this thread before it disappears off the face of the first page....

THis will dissapear as many others have and we will continue to get the "LOWEST DROP" Threads all the time this is how forums are and there isn't much we can do about it. Once day people will learn

[LucasBlack]

Originally Posted by Highrev1

THis will dissapear as many others have and we will continue to get the "LOWEST DROP" Threads all the time this is how forums are and there isn't much we can do about it. Once day people will learn

hehe....you saw the lowest drop thread too huh? haha, i almost responded with some wick cynicism....but i refrained.

[Highrev1]

Its just insane what is important to these members imo. I mean its BS look at the results from this poll....Do you really want to handle better?

But then we continue to get these BS threads Oh well let the neophyte's "feel" that they are handling better.

[LucasBlack]

yeah. i think about it sometimes: i feel that the $200 mods i have planned will make my car handle better than the $1000 susp. mods these guys are throwing at their cars cuz its mad jdm tytz y0!....or something like that. it's like they buy 1000 dollar coilovers, and then only worry about setting the ride height to what looks the best.

...and frankly, i like my suspension travel!! i've learned more and more over the years that "riding like its on rails" doesn't mean that you're actually all that fast. and i think everyone's obsession with lowness stems from what they see on tv...totally disregarding that the racecars on tv are completely different beasts compared to their daily driver. ah well....

[Highrev1]

You must spread some Reputation around before giving it to LucasBlack again.

Come on now you and I both know \/\/\/\/\/ u cool

[sf-si-02]

WTF was that.... your 7th grade power point presentation?

[LucasBlack]

Originally Posted by Highrev1

You must spread some Reputation around before giving it to LucasBlack again.

Come on now you and I both know \/\/\/\/\/ u cool

um....who were you talking to?

[Mitch]

Originally Posted by LucasBlack

yeah. i think about it sometimes: i feel that the $200 mods i have planned will make my car handle better than the $1000 susp. mods these guys are throwing at their cars cuz its mad jdm tytz y0!....or something like that. it's like they buy 1000 dollar coilovers, and then only worry about setting the ride height to what looks the best.

...and frankly, i like my suspension travel!! i've learned more and more over the years that "riding like its on rails" doesn't mean that you're actually all that fast. and i think everyone's obsession with lowness stems from what they see on tv...totally disregarding that the racecars on tv are completely different beasts compared to their daily driver. ah well....

I know it's cliche, but I blame the Fast and The Furious franchise. Those movies, as funny/entertaining as they are, cash in on many of the misconceptions held by "tuners" today.

I used to own an e36 BMW, so I'm familiar with both proper race prep tuning and "street/race" comprimise setups.

[THM8]

i agree with guys. We have always promoted a "correct" suspension setup for a car involves the drivers skill, what kind of driving is being done (autox, rr, street), and what combination of them are useful. So many people run Tein/K sport/etc coilovers for a street car = just confusing.

Adam

[Highrev1]

Originally Posted by LucasBlack

um....who were you talking to?

Not in a bad way I am aggreeing with your "these guys are throwing at their cars cuz its mad jdm tytz y0" Its just insane to me.

[THMotorsports]

Sorry, post up top is ours

[LucasBlack]

Originally Posted by Highrev1

Not in a bad way I am aggreeing with your "these guys are throwing at their cars cuz its mad jdm tytz y0" Its just insane to me.

got ya