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Flashpoint brass shock pistons

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Flashpoint brass shock pistons

Old 02-08-2018, 02:30 PM
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If the argument for a machined piston comes down the circularity or a sprue left over that needs to be trimmed but said machined piston used an o-ring on the perimeter eliminating direct contact between the piston and the body, why not just use a molded piston with an o-ring groove? Tolerances are plenty tight for that and it's easy to drill out the holes based on needs. I can't think of a single reason why a heavier piston is a better thing to have.
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Old 02-08-2018, 03:22 PM
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Originally Posted by fredswain View Post
If the argument for a machined piston comes down the circularity or a sprue left over that needs to be trimmed but said machined piston used an o-ring on the perimeter eliminating direct contact between the piston and the body, why not just use a molded piston with an o-ring groove? Tolerances are plenty tight for that and it's easy to drill out the holes based on needs. I can't think of a single reason why a heavier piston is a better thing to have.
Asking the real questions here.

Weight is bad, period. The management of inertias in transient states is difficult enough with x-way adjustable dampers let alone one-way like RC dampers.
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Old 02-08-2018, 04:53 PM
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Someone needs to weigh these. How much weight can a little piston have? Xray has offered arm weights for years, to calm the cars down. But I don't think adding weight up high on the car is such a good idea.

Generally, shock pistons are made of a soft alloy. Brass should do:


The piston ring (or packing) is teflon coated brass:


Maybe the piston has to be metal. All the oring pistons are metal. Maybe plastic will fail around the little oring cuts.

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Old 02-09-2018, 12:50 AM
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Originally Posted by Zerodefect View Post
Someone needs to weigh these. How much weight can a little piston have? Xray has offered arm weights for years, to calm the cars down. But I don't think adding weight up high on the car is such a good idea.

Generally, shock pistons are made of a soft alloy. Brass should do:


The piston ring (or packing) is teflon coated brass:


Maybe the piston has to be metal. All the oring pistons are metal. Maybe plastic will fail around the little oring cuts.

The forces inside an RC shock shouldn't be too much for plastic, if the correct plastic is chosen. But I suspect machining is easier to do on metal? In the case of the Fioroni w/ ball bearings, that wouldn't work in plastic. So because it needs to be made from aluminum, the o-ring prevents damage to the shock body. I have fioronis, and I'm skeptical about the claim the o-ring seals more on compression.


With full scale shocks, it's important to remember that a shock moves rapidly. And any friction inside the shock causes heat, which causes problems. And an o-ring would cause a lot of friction if it is touching the sleeve

The metal seal, on the other hand, won't deform under pressure, and it has minimal friction, and it's properties don't dramatically change when it gets hot. Granted it isn't a perfect seal, but it must be the best compromise for the application.

The piston is going to be made out of a softer metal than the sleeve, because if there is wear, the piston will get worn rather than the sleeve. It's better to lose some damping than for the shock to blow out catastrophically.


The counter-point to the o-ring seal is a hydraulic cylinder, but that has a completely different set of requirements. A hydraulic cylinder moves much slower, and the priority is to prevent fluid from leaking past the cylinder. So several o-rings that fit tightly in a cylinder is necessary in a hydraulic cylinder, but not for a shock absorber.
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Old 02-09-2018, 01:45 AM
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Lightbulb Adam Drake from Mugen Seiki Racing talks about the Flash Point brass shock pistons.

+ YouTube Video
ERROR: If you can see this, then YouTube is down or you don't have Flash installed.


https://www.youtube.com/watch?v=UbfRmBGVjaE

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Old 02-09-2018, 01:49 AM
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Previous threads on this topic:-

Imbue Performance & Suspension Products

Flash point pistons info

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Old 02-09-2018, 02:12 PM
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Originally Posted by TRiN View Post
+ YouTube Video
ERROR: If you can see this, then YouTube is down or you don't have Flash installed.


https://www.youtube.com/watch?v=UbfRmBGVjaE



Adam talks about the FEELING of consistency, not actual faster lap times.

And at the end he says, "If you want your car to feel light and nimble, you probably want to use standard shock pistons."


Physics dictate that adding weight to suspension components reduces their ability to keep your wheels on the ground, which means less grip.

It seems the argument is that slower suspension means you have the same amount of grip on relatively smooth tracks and on bumpy tracks. But this also means you are sacrificing grip all of the time.

It probably is easier to be consistent if the car reacts the same all of the time, regardless of track conditions. But a more responsive car in the hands of a skilled driver will always be faster.


My goal is to make my car as responsive as possible, to get the most traction available. If conditions deteriorate, I'll adjust my driving style.


I'm also more of a finesse driver, rather than a "point an shoot" driver. That's probably an important distinction. I'd probably be faster if I just put the hammer down more often, but instead I'm always a bit tentative on acceleration.
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Old 02-09-2018, 02:52 PM
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Originally Posted by TRiN View Post
+ YouTube Video
ERROR: If you can see this, then YouTube is down or you don't have Flash installed.


https://www.youtube.com/watch?v=UbfRmBGVjaE

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Old 02-10-2018, 09:26 AM
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