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-   -   Shock Pistons (https://www.rctech.net/forum/electric-road/1041745-shock-pistons.html)

bLamey470 04-23-2019 07:18 PM

Shock Pistons
 
This Goes For Any Car Obviously Other Than The Awesomatix
But Does Any One Run Anything Other Than 4x1.1mm??

I Know In Off Road There Is So Many Different Pistons To Run For Different Tracks/Surfaces
Just Wondering If Anyone Has Tried Anything Else Or Is This Just The Norm We Go By??

Nerobro 04-24-2019 07:59 AM

Tamiya provides several piston hole counts, and I've seen those on various build sheets. Hudy sells at least four different pistons.

I think you're just not seeing it. also.. there's an aversion to really doing shock tuning. I think that may have lead to the current generation of "lets tune flex"... but that's the cranky old engineer in me speaking.

KE4PJO 04-24-2019 08:14 AM

You can't compare "off-road" shock tuning to "on-road" shock tuning. For obvious reasons, unless you have jumps, whoops or wall climbs on your "on-road" track...

Nerobro 04-24-2019 08:27 AM


Originally Posted by KE4PJO (Post 15437855)
You can't compare "off-road" shock tuning to "on-road" shock tuning. For obvious reasons, unless you have jumps, whoops or wall climbs on your "on-road" track...

Yeah, you can. :-) Many of the same factors come into play in both places. Shocks are "a thing" what you do to the shocks is another thing. Packing, frequency damping curves, are all "a thing" you can meausre, and get useful data on. I can't recall the last person I saw talking about suspension frequency, or considered the difference between compression and rebound damping. Changing the speed at which the dampers pack up (affected by size of piston holes and fluid viscosity)


KE4PJO 04-24-2019 08:48 AM


Originally Posted by Nerobro (Post 15437869)
Yeah, you can. :-) Many of the same factors come into play in both places. Shocks are "a thing" what you do to the shocks is another thing. Packing, frequency damping curves, are all "a thing" you can meausre, and get useful data on. I can't recall the last person I saw talking about suspension frequency, or considered the difference between compression and rebound damping. Changing the speed at which the dampers pack up (affected by size of piston holes and fluid viscosity)

OK...

LzREngineering 04-24-2019 09:15 AM


Originally Posted by Nerobro (Post 15437869)
Yeah, you can. :-) Many of the same factors come into play in both places. Shocks are "a thing" what you do to the shocks is another thing. Packing, frequency damping curves, are all "a thing" you can meausre, and get useful data on. I can't recall the last person I saw talking about suspension frequency, or considered the difference between compression and rebound damping. Changing the speed at which the dampers pack up (affected by size of piston holes and fluid viscosity)

Most people get scared by the maths and just copy each other. 4x1.1mm pistons are, however, quite versatile, IF you keep the temperature and suspension frequency in mind. I've got 3x1.1mm with 250w oil in my "wet" car; similar damping ratio with slightly faster pack, but calculated at a lower temperature.
I'm waiting to try a 4x1.1mm on compression/3x1.1mm on rebound 2-way piston, but nobody makes them for TC shocks.

Nerobro 04-24-2019 09:26 AM


Originally Posted by LzREngineering (Post 15437896)
I'm waiting to try a 4x1.1mm on compression/3x1.1mm on rebound 2-way piston, but nobody makes them for TC shocks.

That's in my queue of things to make.

bLamey470 04-24-2019 10:42 AM


Originally Posted by Nerobro (Post 15437847)
Tamiya provides several piston hole counts, and I've seen those on various build sheets. Hudy sells at least four different pistons.

I think you're just not seeing it. also.. there's an aversion to really doing shock tuning. I think that may have lead to the current generation of "lets tune flex"... but that's the cranky old engineer in me speaking.


no I know they all have different pistons itís just 99% of the setup sheets everyone runs 4x1.1 and just curious if that just works the best or people are afraid to try stuff...

bLamey470 04-24-2019 10:44 AM


Originally Posted by KE4PJO (Post 15437855)
You can't compare "off-road" shock tuning to "on-road" shock tuning. For obvious reasons, unless you have jumps, whoops or wall climbs on your "on-road" track...

i know I understand that Iím just saying that people seem to change pistons in off-road far more than Iíve ever seen on onroad just curious why 99% of people run 4x1.1 rather than anything else

bLamey470 04-24-2019 10:48 AM


Originally Posted by LzREngineering (Post 15437896)
Most people get scared by the maths and just copy each other. 4x1.1mm pistons are, however, quite versatile, IF you keep the temperature and suspension frequency in mind. I've got 3x1.1mm with 250w oil in my "wet" car; similar damping ratio with slightly faster pack, but calculated at a lower temperature.
I'm waiting to try a 4x1.1mm on compression/3x1.1mm on rebound 2-way piston, but nobody makes them for TC shocks.

Ok thatís what I was figuring but wasnít sure if that was the case, cause I would think that there would be different piston setups from carpet or asphalt and to tight tracks to open tracks I just donít get enough track time to really go out and test things like that, and a 2 way piston would be pretty awsome

Troy Carter 04-24-2019 12:14 PM

My personal opinion is that TC's typically react to other chassis setup changes more noticeably than shock piston changes so this is usually low on the list. Changing fluid can be useful to suit the conditions and driving style, and effect balance if changing one end of the car. But other setup changes can be more influential and are often easier to make and put back.

A couple years ago I tried a bunch of stuff: Oil weight, progressive pistons, tapered pistons, flapper pistons, number/size of holes, machined pistons. Since trying that I've standardized on 4 x 1.1 pistons and I rarely ever change the oil unless the car needs an overall change in how it reacts. It may just be me but I couldn't feel those changes very well, sometimes the tradeoffs were something I didn't like, and it's more work than I want to put in. I know some guys who can really feel the shock setup changes but I can't and basically stopped playing with the pistons.

1spunspur 04-24-2019 06:21 PM

In my days (mid '80's) our main concern was shock oil viscosity,temp. & foaming. I still don't understand why you would want to change pistons when it's so much easier to change the oil!?

Number1b3 04-24-2019 07:36 PM

Itís funny every used car I buy comes with all those left over pistons lol

Nerobro 04-24-2019 08:35 PM


Originally Posted by 1spunspur (Post 15438271)
In my days (mid '80's) our main concern was shock oil viscosity,temp. & foaming. I still don't understand why you would want to change pistons when it's so much easier to change the oil!?

That's a good question! So shocks damping is based on velocity. The speed at which the shock "packs up" or it reaches the sharp curve where the shock effectively locks up. That's more affected by orafice diameter. The smaller the hole, the slower the fluid speed where the shock packs up. Even if you change the fluid viscosity.

rccartips 04-24-2019 11:54 PM


Originally Posted by bLamey470 (Post 15437966)
no I know they all have different pistons itís just 99% of the setup sheets everyone runs 4x1.1 and just curious if that just works the best or people are afraid to try stuff...

Bunch of stuffs have been tried and 4x1.1 is good for most scenarios. TC shocks only move 2mm, so even less of a factor compared to off-road.


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