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Old 01-14-2012, 04:32 AM   #1
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Default C2 shock absorber pistons

This thread is for the new dual stage C2 shock pistons. C2 is an Italian manufacturer of racing shock pistons for the R/C Market.


To learn more about C2 you can visit c2shocks.it

Stay Tuned...

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Old 01-15-2012, 11:58 AM   #2
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Wow I am a bit amazed then not a single comment on probably what amounts to a real step forward in 1/8 RC shocks??

I wondered when somebody would actually step up with a proper shock piston that is leaps and bounds beyond this tapered this, cross drilled holes that products. Actually I am a bit pissed at you because I saw a way to make some money with a limited capitol investment and you beat me too it.

Well played sir, well played!

In all seriousness I was dumbfounded why nobody has done this already. I have what I would term a decent background in suspension and shocks. Having owned an offroad specialty shop and fabrication business in San Diego Ca, black rhino performance (Mods that not a plug my partner ran it into the ground when I went overseas so don't buy anything from that idiot!) Did quite a bit of development work with i-Shock, Fox Shocks, hydrodynamics and King including building some race vehicles. So I have spent a fair amount of time building shim packs and checking telemetry results on a few coilovers in my time.

So I must say that this is the first product I have seen that is actually a functional scaled down version of full size coil over shock piston. Outstanding!

Do you plan on having shim packs of various thickness or materials with different stiffness down the road?

I see that you went with the compression side shim first but it would appear that you have a design with a dampening side shim due out maybe too? I always found that setting up the dampening shim pack to be far more difficult and time consuming then the compression side. Hats off for doing the port reliefs on your pistons (from what I can see from the Solidworks renderings that is or do you use Pro-E?) Regardless.

Guys this would appear to be the real deal of shock pistons, If I wasn't over here in Asscrackistan I would be all over these!

Mr. Cesaretti watch out though I still think I have a solid 16mm piston design...LOL

Cheers mate and best of luck to you!
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Old 01-15-2012, 12:21 PM   #3
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I see you do have various shims I didn't catch that the first time through the site.
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Old 01-15-2012, 12:43 PM   #4
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I don't get it how these work and the website isn't very clear :/
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Old 01-15-2012, 01:19 PM   #5
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Morgoth, these work the way big vehicle shocks work by controlling flow differently based on how fast the piston moves through the oil. With these there should be some level of control between high-speed damping and low speed as well as different damping for rebound from compression. That's the gist, Contingency could explain much better.

I see a challenge in calibrating these. In a 7-8 lb car, what is a fast or slow piston speed? Another issue I see is that for RC, we're always challenged to have a light enough damping to allow movement over small bumps and still enough damping to resist bottoming. With big shocks, usually the high speed damping circuit is the softer one to allow for sharp bump compliance, that would lead to bottoming over jump with our cars.

I'm speculating, the website doesn't appear to be very clear so maybe they've addressed these things.

For years we've had plastic pucks in our shocks. It appears that finally someone has done it.

How do I get some?

Cost = 25 euro for a set of 4 (Team edition), pretty reasonable.
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Old 01-15-2012, 01:36 PM   #6
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Yeah Website really does suck, and the more I dig into it I cannot find a single actual picture of the piston and components only of a bump stop and some internal shock spring. The bump stop doesn't look functional to me and the internal shock spring I do not buy either. I have done a lot of coil over and coil carriers with bypass shocks set ups but we never stuffed any springs inside of em...LOL

I would be interested in seeing an actual picture of the piston and components to see the quality of machine work...I mean I could draw up an awesome intricate 16mm piston in Solidworks but making it would be another story.

Principal is sound and I'm no tech writer but basically what you want to achieve is a different rate of compression and rebound. Compression dampening is a speed related function of the piston head. Rebound dampening is the control of the compressed spring force and unsprung weight and it's inertia.

What the shims do on a piston head is actually deflect based upon the actual speed of the piston to create a variable orifice size for fluid flow.

In this piston there are shim(s) on the compression side of the piston so in theory is provides a variable rate for the compression stroke and a fixed rate pr I should say a fixed orifice size for the dampening stroke. Biggest difference here over any "toy car" piston I have seen is that you have two distinct rates of fluid dampening between compression and rebound. By that I mean the orifice size on the compression stroke is distinctly different then the orifice size on the rebound stroke. Depending on the shims available in the kit it may actual provide a superior variable compression performance far greater than the standard ie. 8 x 1.3mm pistons.

So you can have a more responsive shock that will still be firm without feeling like it's packing up. But the bottom line is having two distinct orifice sizes between compression and rebound. Since nobody makes a progressively wound spring (yet) for shocks the rebound will be more of a fixed rate to some degree compared to compression rates. By that I mean The rebound dampening is more about trying to keep the shock from topping out and a more linear function of dampening compared to compression.

But yeah as Davidka stated...everybody has been selling you glorified plastic pucks up to this point you get some variable compression just based on the fluid dynamics but you still got a plastic hocky puck with holes in it.

I hope that makes some sense but I probably made it sound way more confusing then it really is.

Last edited by Contingency; 01-15-2012 at 01:52 PM. Reason: Fixed spelling, and tried to clarify
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Old 01-15-2012, 02:17 PM   #7
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Quote:
Originally Posted by Davidka View Post
I see a challenge in calibrating these. In a 7-8 lb car, what is a fast or slow piston speed? Another issue I see is that for RC, we're always challenged to have a light enough damping to allow movement over small bumps and still enough damping to resist bottoming. With big shocks, usually the high speed damping circuit is the softer one to allow for sharp bump compliance
See this is another obvious solution from full size race vehicles to RC level. Too much emphasis is being placed on the piston/fluid viscosity to achieve compression control...I mean we don't change fluid viscosity in real shocks to compensate for different spring rates. The spring itself is supposed to be keeping the car from bottoming out..(bypass shocks excluded).

What I see missing on RC level shocks are variable wound springs and also running two different springs with a spring carrier bushing. Christ you could make one easy out of delrin. There should be two springs, say one with a rate of 3.5 pounds and one with a rate of 4 or maybe 5 pounds stacked. Just like we do on a full size coil carrier shock. The lighter spring covers 75% of the shock travel and the heavy spring does the last 25%. This way you are using the spring to absorb the load and the shock to control the spring not vice versa which is what I see now.

Hey maybe I should build that to offset my hobby expenses...progressive wound first stage springs with a stacked second stage spring..LOL
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Old 01-15-2012, 02:19 PM   #8
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TKO has drivers testing the pistons. Losi drivers have tested them and we will have revised test pistons shortly. The ones we had worked well.
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Old 01-15-2012, 02:47 PM   #9
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TKO has drivers testing the pistons. Losi drivers have tested them and we will have revised test pistons shortly. The ones we had worked well.
No doubt, if they can be mfg and retailed at that price point and still carry at least a 30% wholesale margin and I was in the industry. I would be tossing some cash out for exclusive distribution

This guy is going to have lots of people sniffing his leg once the word gets out but he needs somebody to seriously help him on his web page development and I would still want to see some photos and not CAD renderings.
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Old 01-15-2012, 04:31 PM   #10
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Quote:
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TKO has drivers testing the pistons. Losi drivers have tested them and we will have revised test pistons shortly. The ones we had worked well.
Since TKO also sells tapered GHEA pistons maybe they could see how good they compare to these. Im sure the C2 is a step in the right direction.
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Old 01-15-2012, 05:37 PM   #11
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I found more content on the web page in .pdf form. Usually links called "info" or instructions. There are component photos but they're pretty small and not very high quality.

Contingency, there have been and still are dual-stage pistons out there. RPM came out with some back in the early 90's with a simple flapper plate arrangement that covered half the piston holes in which ever direction that the piston was oriented in. A small company called Mantis Worx is doing a similar design for 1/8 and SCT cars now. PAragon made some pistons I tried years ago that had one large hole and a long tapered needle in the shock that varied the size of the port (smaller as the shock compressed). It had a little promise except for the issue that it didn't have a separate rebound circuit.

I've seen dual spring setups like you describe on monster trucks and 1/5 scale shocks but don't believe a lot of R&D went into any of them.
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Old 01-16-2012, 07:02 AM   #12
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First, sorry for my terrible English

In this moment I can not insert images, because of forum rules, but...

TEAM EDITION Pistons --> more information here
c2shocks.it/pdf/news9.pdf

RIDE CONTROL Pistons --> more information here
c2shocks.it/pdf/news8.pdf

CONTRACTIVE SUSPENSIONS --> more information here
c2shocks.it/pdf/news7.pdf

You can see a picture of the standard pistons here
c2shocks.it/shop/product_info.php?products_id=38

The new pistons are made in Delrin and stainless steel.

For more information write me to info@c2shocks.it

Grazie!!

Tiziano
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Old 01-16-2012, 09:26 AM   #13
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Yeah I would suspect that there would be numerous variants and ideas for dampening control as this hobby tends to draw people that tinker.

From the drawings this C2 shock is not just a "check valve" type system like say the flapper that you mentioned. One reason is this piston assembly is a good micro rendition of an actual full size shock sans the rebound shims on the top. It has the proper reliefs on the alternating ports underneath the shim pack just as you would find on some full size coil overs, it utilizes multiple shims and spacers creating an actual shim pack. you can adjust it by pulling out shims or spacers or combining them in various configurations. So if the shims are actually performing like a full size shock and have the proper spring tensile to create a flutter pack then it brings the RC shock a huge step forward. Time will tell?

I think that lots suspension performance gains could also be realized using dual rate (two) springs. There isn't much innovation on the spring side that I see. Maybe some goofy stuff tossed together to look cool but nothing as you pointed out done from a true suspension tuning aspect. Lots of various progressive rates can be created using a dual rate spring system and these shock bodies are ideal for it.

One other thing and then I'll lay off this thread as it is a C2 thread..That is why use ridgid droop stops instead of limiting straps? Why put all that load on the center of the lower hinge pin and control arm instead of the shock mounts where it should be?
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Old 01-16-2012, 10:10 AM   #14
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Quote:
Originally Posted by Contingency View Post

One other thing and then I'll lay off this thread as it is a C2 thread..That is why use ridgid droop stops instead of limiting straps? Why put all that load on the center of the lower hinge pin and control arm instead of the shock mounts where it should be?
Part of the reason is to protect the shocks themselves. They have shown to not be strong enough to handle the forces in crashes. Mugen's aluminum shock caps used to become oblong and break when running unlimited droop setups in the past for instance. Shock ends have also pulled out/broken from this.

I must correct myself from my earlier post, the 2-stage pistons referenced as "Mantis worx" are made by RC Shox. Mantis Worx is the owner's screen name in this forum.
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Old 01-16-2012, 12:16 PM   #15
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I can't wait until people start running these and report back on RCT. I'm one of the guys still waiting for Tex's Magna shocks, so these pistons certainly have piqued my interest.
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