Piston choice is often more the question here.

For rough, rutted surfaces, it is recommended to run a larger/fewer hole piston and slightly thicker oil. This allows the shock to work quickly on the "chatter" type bumps, getting the wheel back to the ground quicker and not "pack up" on compression.

The down side to larger hole pistons is that they do not "pack up" as much as more or smaller hole pistons. If the track has a jump that shoots you high, with no downside landing, a smaller hole with more holes piston works better here, providing more high shaft speed damping (pack) when flat landing a jump, keeping the chassis from bottoming out (the dreaded "chassis slap").

VRP or Vision Racing Products has come out with an effective manner to provide the best of both worlds with their Game Changer pistons. The GC pistons have both dynamic compression and rebound valves. On rough, rutted surfaces, you can get the suppleness needed to keep the wheels on the ground for maximum traction. The additional rebound flaps/holes help get the wheel back down to the surface quicker. The Carbon Fiber Compression Valves actuate at fast shock shaft speeds, as in the example of flat landing a jump. The CFCV closes a few holes, helping the shock pack up, only when needed.

I've been running the GC pistons for a little over a year now, with great success. I'm constantly comparing them to the latest, trend build of shocks for my car. I keep a second set of shocks with the preferred pistons, springs, oil and build type (emulsion in this case) in my box. I have yet to find the standard piston setup better than the GC shocks, across the multiple tracks that I race at.

Lastly, I've tried the GC piston shocks with both emulsion and bladder builds. The best lap times and handling were achieved with a bladder build, using vented caps, custom drilled (extra 1.5mm vent hole) with maybe 25% rebound. I also test between the legacy and new low frequency springs that Tekno offers. Again, best lap times and performance were with the legacy springs.

1/8th scale, 4WD vehicles have a lot to consider for optimizing performance. Break it down, testing specific features to learn what works best for you.

Best advice that I've followed: if I make a change and it does NOT show a noticeable improvement, undo that change. Even if the change appeared to have NO effect, undo it. If you don't, you can eventually make so many changes away from your original setup, that the car becomes undriveable.

wich GC piston and legacy spring for 48.4?

I buy the 8x1.3 Low Pack GC pistons and drill them as follows:

4 open holes: 1.6mm
2 rebound holes: 1.8mm

Leave the 4 holes under the CF compression valves stock at 1.3mm

I run PT oils, 500cst in the rear, 475cst in the front in the hotter months (80F and above). Cooler oils are 475R/450F

Legacy springs: Pink front, Red rear.

Dear RCtechers,

What would the effect of having a bladdered shock but have a tiny hole drilled in the end cap to allow trapped air to escape?

Wont you get the effect of a emulsion shock without having air and oil mix together?

Would this work on the rc car?

-Alexander

Over the years I've noticed that people consistently neglect this when claiming they've tried bladder VS emulsion "back to back". Truly I'm agnostic on the subject, but it's possible that those who liked emulsion better over bladder merely needed thinner oil on their setup to begin with (or vice versa).

This is commonly used across most of the manufacturers. Works well. Rebound is strictly based on the elasticity of the bladder.

Currently, I use Tekno EB48.3 stock version Bladder shocks. The new EB48.4 comes with standard emulsion shocks.

After couple runs, I noticed my bladder gets ripped and I need to replace them. For cost reasons, I would like to go with emulsion shocks so I don't have to keep buying the bladders.

Do I need to buy the vented or non-vented shock caps if I want to go emulsion?
Do I just remove the bladder and build it like an emulsion shock ?

Are you adding bladders to your .4 shocks? I ask this for a specific reason.

The new multi-function cap, that comes with the .4, allows us to run emulsion, vented bladder and sealed bladder builds.

However, the inside of the .4 cap is different than the .3 and down caps. The .3 cap has an extra "pocket" milled into it, allowing the shock shaft to travel up farther before the top of the shock shaft (or nut) pinches the bladder.

If you inspect your bladders, are the punctures shaped like an oval, near the middle of the bladder? If so, that oval is from the bleeder hole on the underside of the .4 cap. Without this extra milled pocket of the .3 cap, the shock shaft will pinch the bladder on the underside of the cap, cutting it, typically at the bleeder hole.

There are a couple of solutions:

1.) Use the .3 caps for bladder builds
2.) Shorten the up travel of your shocks by screwing the shock end on further
3.) Use the original .3 shock cartridge set (TKR6146)

For #3, just before the .4 came out, Tekno released a revised shock cartridge set: TKR6146B. The main difference is the lower bushing is shorter allowing for more up travel. This new cartridge set is standard in the .4, giving additional up travel.

Thanks for the detailed explanation. Currently I only have the .3 Caps and TKR6146B the revised shock cartridge set. Also I use Delrin pistons from Tekno.

The bladders have rips on the side not in the middle. The shock shafts definitely don't hit the middle of the bladder. There are NO rips in the middle of the bladder. I think the air pressure builds up and rips only the side. This happened four times and it costs me to keep buying these bladders.

So I want to use Emulsion shocks going forward. Can I build emulsion shocks with .3 caps or do I need to purchase .4 caps?

Thanks,

To build emulsion shocks, you'll need either the new .4 (aluminum) caps or you can use the plastic caps from the SCT. You'll need to get the appropriate o-ring seals for each.

Oh got it, thanks for the explanation!

Agreed, but what do I know...

But one could just look at the high-diver competition in the Olympics* for evidence that this is true. In order to soften their "landing," the water itself in the landing zone is aerated.

Anyone care to give an educated guess of how much "thinner" in cst a fully-emulsified mixture of air/oil would create? Maybe -50cst? Maybe more? So in other words, a emulsion shock built with 500cst on the bench acts like a shock with 450cst on the track?

* Correction: The correct term is sparging, and apparently, it's only done during practice.