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RC Shock Dyno Test Results

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RC Shock Dyno Test Results

Old 03-01-2015, 06:09 PM
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I would like to know if there is really much difference between the Kyosho x-gear springs, TLR low frequency springs, and the others.

I also would like to know if the type of o-rings make a diffrence. O-ring vs grooved vs x-ring.
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Old 03-01-2015, 06:28 PM
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Originally Posted by orangutanracer
I would like to know if there is really much difference between the Kyosho x-gear springs, TLR low frequency springs, and the others.

I also would like to know if the type of o-rings make a diffrence. O-ring vs grooved vs x-ring.
I'm +1 on o-ring vs x-ring. Also what affect does the surface finish of the shaft. Maybe a more fundamental question is ho significant is the sliding friction in the overall performance of the shock at various conditions.
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Old 03-01-2015, 06:30 PM
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I'd love to see how a Shepherd onroad shock with its spring loaded floating piston design for volume compensation does. I can send you one if your dyno can handle shorter shocks. PM me if interested.
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Old 03-01-2015, 06:38 PM
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That sounds like the old Delta shock design. They worked great but are hard to build consistently.
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Old 03-01-2015, 06:38 PM
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Is there a link I'm missing to the comparison
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Old 03-01-2015, 07:03 PM
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Originally Posted by fredswain
That sounds like the old Delta shock design. They worked great but are hard to build consistently.
Sort of except the Shepherd piston is at the top just like a bladder and it's probably the easiest, most consistent and long lasting design I've ever used. It's just a slightly updated version of the good old Picco shock that people have loved since the 90s.
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Old 03-01-2015, 07:10 PM
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this is too cool thank you very much icecyc1
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Old 03-01-2015, 07:34 PM
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Originally Posted by TOO-TALL
Is there a link I'm missing to the comparison
scroll down in the original post. looks like his sig, but you'll have to copy/paste the link into a browser tab.
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Old 03-01-2015, 08:07 PM
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Originally Posted by gatorage

like the test show bladder with foam is real consistent which is a good pick on a track where you have similar conditions from start to finish(for sure what i would pick for onroad) this is also what i like most the time for 1/8 buggy i guess because i run higher oil and having more weight the 1/8 conditions dont change as much as the smaller 1/10 on the same track.
Interesting observations. I find conditions and performance changes more with 1/8. Longer mains, rougher track, bigger hits, bigger temperature swinga (outdoors), etc. I've always found it curious how we keep landing on the emulsion setup in 1/10 since we run in comparatively consistent conditions.
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Old 03-01-2015, 08:12 PM
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Default Thanks everyone for the comments!

I'm very excited to see the positive comments from the report. I really hope everyone learns from it. Like I said, I'll be using your comments to come up with further test plans that will hopefully drill down into further details that you all would like to know.

Some of your ideas will help me to develop a test (like the friction, or the long/short stroke) tests to best understand the effects. Some involve specific products, which I probably can't test specifically, but I'll try to design a test in general to cover the physics involved.

I think my next plan is to come up with a way to measure higher speed data for the Impact Testing (like your car will see on jumps). This seems to be highly desired data, so it will give the biggest benefit at this point.

The bladder test seemed to raise a lot of comments, so I'd like to go deeper into that as well. I have to say this test was a one data sample test. I only used one bladder. I was intrigued that the data looked as it did, with the collapse, but I was able to get rid of it by not venting the bladder. That told a great story. But, to be thorough, I should test several bladders, they are NOT all the same for sure. I'll be getting my hands on some soon, so I'll test and post results.

I'll also be doing a more thorough study of pistons. I think the flat pistons have shown what they do pretty consistently now (except I need to include high impact velocities still), so I'll focus on the fancy pistons. I will say I have a couple versions right now, and I did a limited single test, and yes, it did behave as the manufacturer claims, at least in the one test I did run.

I do want to say that my testing is not intended to glorify or bash any manufacturer, so I'll try to keep the results generic. But, I will likely post a photo of the test specimen, and chances are, people may figure it out due to the unique look. I just want people to be informed, and if a company makes something that should help performance the way they say, then the truth will be evident in the data. I also can't test every combination from every manufacturer there is either. I wish I could, but the money and time (mostly the time) it would take is beyond my limited resources.

I'm currently focused on Off-road shocks because that is what I own. I have some 1/10th big bore, and some 1/8th big bore shocks that I'll be doing the majority of my test work on. I don't have any experience with on-road, so that might not be for a while (sorry!), but hopefully the general trends and physics apply just the same. Maybe some day, I'll get a chance to test on-road shocks too, but I've got a lot to learn at this point still.

There was one mention about the hysteresis of the dyno itself. Valid question. I will say that I spent a couple months working through the dyno and instrumentation issues before becoming comfortable enough with the end result data. What sealed the confidence deal was the fact that I got perfect lines with the bladder design (no hysteresis), and very repeatable curves with the emulsion (definite hysteresis). I believe if the dyno itself had hysteresis issues, it would have been evident in all runs. I have tremendous confidence in the data below 250mm/s, but above that I hesitate until I become more acquainted at those higher speeds. (it really seems quite fast, and it makes me afraid I'm going to wreck my shocks!)
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Old 03-01-2015, 08:25 PM
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Originally Posted by Fastforward
I'm +1 on o-ring vs x-ring. Also what affect does the surface finish of the shaft. Maybe a more fundamental question is ho significant is the sliding friction in the overall performance of the shock at various conditions.
Orangutanracer's question about the different o-rings is definitely interesting. Friction is always a topic of discussion at every level, and deserves a test. Friction tests, to do them properly, require a bit different methods. I did a quick and dirty by just running a shock with no oil at the same speed I ran with oil and got a result. The result show I had about +/-1N of force. Comparing that to the 10-20N that the damper provides it's not much, but many would argue it is still significant. I did get a different brand shock from a friend, and I did notice and measure a larger amount of friction from the seals. So, as the quote above says, I'll try to design a test that shows the significance of the sliding friction vs the overall performance. If it proves significant enough, then maybe a specific seal type test is in order.

Thanks for the feedback.
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Old 03-01-2015, 08:29 PM
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Originally Posted by orangutanracer
I would like to know if there is really much difference between the Kyosho x-gear springs, TLR low frequency springs, and the others.
Springs are out of scope at this point, but it is interesting, and I'll keep it in mind for the future. Most of the time springs can be characterized simply with a scale and a ruler because they are displacement dependent and not velocity dependent. I'm not too familiar with the claims of the springs you mentioned.
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Old 03-01-2015, 08:46 PM
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A word on x-ring vs. O-ring: While an o-ring comparison may be useful, there are many other variables in a shock's working friction. Some shocks require different guide bushing configurations to work correctly. These variables may reduce the efficacy of these tests.

What I like about what has been done so far is that the things these tests have focused on are consistent across brand and type.
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Old 03-01-2015, 09:47 PM
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Originally Posted by Davidka
Interesting observations. I find conditions and performance changes more with 1/8. Longer mains, rougher track, bigger hits, bigger temperature swinga (outdoors), etc. I've always found it curious how we keep landing on the emulsion setup in 1/10 since we run in comparatively consistent conditions.
no is said same track and for a 1/10 scale car vs 1/8 on same track. so to scale! the track is more inconsistent as a %... i run much lighter oil in 1/10 scale car so it moves around a lot more and at a higher rate of speed even more than my 1/8 at more weight. so on the same track my 1/10 shock are working harder as far as movement. yes in a long main the shock will come inconsistent with heat but i was talking about track inconsistent effect on movement of the shock. now cuz emulsion have bad inconsistency as a shock it might be another good reason not to run it on 1/8 buggy in long mains for the heat expansion of air vs just oil(but not sure of that test)!!!
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Old 03-01-2015, 09:58 PM
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Originally Posted by gatorage
no is said same track and for a 1/10 scale car vs 1/8 on same track. so to scale! the track is more inconsistent as a %... i run much lighter oil in 1/10 scale car so it moves around a lot more and at a higher rate of speed even more than my 1/8 at more weight. so on the same track my 1/10 shock are working harder as far as movement. yes in a long main the shock will come inconsistent with heat but i was talking about track inconsistent effect on movement of the shock. now cuz emulsion have bad inconsistency as a shock it might be another good reason not to run it on 1/8 buggy in long mains for the heat expansion of air vs just oil(but not sure of that test)!!!
The effects of heat and air expansion causing fade is interesting. I'll see if I can come up with a way to make a test that is repeatable to measure those effects. What do people believe are the most critical components to causing fade? Piston type? Oil? Bladder/type? (yes, I know heat is the issue, and that's caused by the shocks working hard and heating the oil over time) What do you racers typically do to prevent or minimize the fade? I can then test a worst case and a best case scenario and see how much different it is.
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