Davidka

iTrader: (86)

That design is sometimes employed in full scale racing (I had a pull/through shock on a full suspension mountain bike about 15 years ago). I can't find any evidence of an off road shock design from AME.

roosterreagan

iTrader: (16)

[QUOTE=wittyname;14783642]RC is funny ....

Grown man with job spends hours building and rebuilding his shocks to attain perfection , sets down car , hits wall 23 times ...

Kid picks his nose , drops down his b4 , and laps the field .... shocks don't even have oil in them ...

^+100

Back to subject, having hydrolocked a losi mini t plastic shock and splitting in two when I compressed it, I do understand some of the discussion, that being said, why are there so many options for shock pistons (hole dia., # of holes, taper, etc) if they all just act like a hydraulic cylinder piston? Would bigger piston holes and an air tight shock act like a full scale shock? And/or thinner shock oil that actually passes through said holes in a manner fast enough to keep up with compression and rebound? That seems it'd be most consistant. I've been putting a lot (some would say too much) of thought into this subject lately, and just like the above quote it will NEVER actually keep me off the walls a 17 times per lap but I'm one of those special masochistic kinda nerds. Any thoughts on how to make our shocks actual oil shocks instead of air bag suspension?

Davidka

iTrader: (86)

The reason for different size holes and oil weights is that different combinations create different turbulence & flow resistance at different piston speeds.

There are a few companies making directional flow pistons but none are as sophisticated as a full scale shock's directional vslving, wave washer stacks, and in the case of race level stuff, mukti circuit systems (damping control of volume overflow). Due to their tiny size, our stuff is pretty basic.

roosterreagan

iTrader: (16)

Cool, seems we have a similar understanding of full scale suspension theory, maybe my rambling on this subject will make sense to you. My thinking is that simple air over oil, or emulsion type, or cartridge type etc. shock theory should scale. I think that with the extreme viscosities that are common place the tiny holes in pistons are inconsequential, I can visualize that during compression the rapid movement of the piston "cavitates" the oil into a frothy foam-like consistancy, thereby making it thinner and allowing the piston to pass through, and in a path-of-least-resistance scenario the oil only by-passes the piston on the periphary. In this scenario I can maybe see where tapered pistons might have some legitamcy. Hows bout thinner oil, bigger holes, tighter tolerances (piston to inner shock body walls) or "piston rings" (pistons have an axial groove on the periphery for thin o-rings to act as 'piston rings'), would then our 1/10 scale shocks act more in accordance with full scale examples? What about 2 big holes, maybe the same diameter as the shock shaft hole, both in line with the shaft hole, a strip of lexan (just wide enough and long enough to cover both through holes), a hole in the center of this strip the same diameter as the shaft, slipped over the shock shaft and held either under or above (depending on desired results, but I would think above piston would result in slower compression/quicker rebound) the piston with the e-clip or screw/washer, effectively acting as a one-way valve, shunting oil flow in one direction and allowing close to normal flow the other. Of course this hypothesis hinges on the idea that the piston holes (and mostly only the piston holes) are the metering factor of flow. Thoughts, critiques?

Davidka

iTrader: (86)

All of those things are available. Fioroni used to make alloy pistons with an o-ring and VRP, MIP make pistons with effective one-way valves (MIP's are even adjustable).

As for the thin viscosity/fine valving? I'm not sure why it doesn't work, or why "big-bore" is effective as that isn't done on full scale suspension either.

I've thojght a 2-stage compression damping could be useful but I can't figure out how we'd achieve both small bump compliance (high-speed damping) and chassis weight transfer (low-speed damping) while retaining bottoming resistance, which is where our little cars differ from full scale so much.

chuck c

asked this question on rc8b3e thread got no response. has any one tried fioroni t.a.p. 8x1.2mm 2ball/8x1.3mm 4ball pistons. or vrp x2/ vrp game changers. on rc8b3e. if so witch ones.trying to stop chassis slap. or should i try emulsion first before spending big money on any of these.

fenton06

iTrader: (24)

Not the greatest advice here but some chassis are just belly slappers.

Davidka

iTrader: (86)

Before spending on exotic pistons, try going to smaller piston holes and go down in oil weight to compensate. This should ad "pack" (high speed compression damping) and resist bottoming. It will also alter handling a little (maybe for the better?) . No free lunch, as thet say.