Flashpoint brass shock pistons
 

Anyone tried these brass pistons?

Any input would be great! I didn’t find any information about these on the search.

Thanks!

My only question is what is the difference between using a heavier piston to slow shaft speed verses simply going with a thicker fluid?

The pistons are also thicker than stock pistons and also have o-rings on the OD to prevent blow by... so its not the same simply going with thicker oil.

Provided someone is using machined pistons, then wouldn't the blow by be the same net effect as selecting a slightly larger piston hole size?

***EDIT
I recall there was an issue with Fioroni pistons that were having rubber seals sticking on the walls of the shock body suggesting that blow by was desired for some racers. I also read that some folks were having swelling issues and needed to replace the rubber seals more frequently than anticipated, I wonder if Flashpoint is doing anything to mitigate these concerns?

The oil blow-by keeps the pistons centered and off the walls of the shock. Xray has been using small pistons for decades. (and people have done nothing but complain about it) Note the lack of anodizing wear inside the shock compared to tightly fit shock bodies. But if you go too small, the piston can auger into the shock wall and jam up. It's a pretty fine line.

Look up "over-boring" in the paintball world. Same principle, just air instead of fluid.

My friend is running the 1.5 2 hole ones in a b6 on turf. He admitted he bored the piston holes out to 1.6 so there is no more beveling on the piston hole walls. He has been running for 2 months and really likes. The swelling O ring issue mentioned is something to consider. Maybe they are planning on that issue as part of the blow by reduction? Just like with any piston, which there are dozens of styles, it seems to be up to personal preference these days. Cool concept and some seem to really like.

Why not just run close fit machined teflon pistons instead? They'd have far less friction between the piston and the shock wall. A rubber o-ring is going to have stiction.

There is more to this that no one knows. I know guys that won't race with them everywhere. They use nothing else

Great feedback!

So the o ring swells over time and needs to be replaced.

Also, where would I buy those machined tephlon pistons at?


Thanks!

CNC machined pistons are becoming industry standard for most brands nowadays, if your kit comes with mold injected pistons then chances are you will need to sand/file the injection point off the tree and that leaves inconsistent roundness between the pistons where a CNC piston is perfectly round (just like the brass pistons), you just need to decide which option is best for you.

I currently run flat CNC pistons in most of my cars, I've tried some 2 stage pistons, but can't definitively say they work for me because the tracks I run are all smooth hard pack dirt or turf.

I have heard they are excellent and are thinking about giving them a try.

They better moldings have the injection at the corner edge of the piston, if you have to scrape it with a knife, it's just the top edge, nothing that'll effect the roundness of the piston. (Xray pistons again)


Didn't RM sweep the worlds with these pistons? They can't be bad.

The conversation has been about the shape of the piston and sealing against the shock body, but why is heavy a good thing? Is it good? These pistons could be made out of any material; they could make the same shape piston out of plastic or aluminum, with or without the O-ring. So why brass? Why heavy?

An issue negatively affecting an RC's suspension is how much unsprung weight there is compared to sprung weight. And these pistons add to the unsprung weight, right?

It reminds me that Mugen offers heavy pivot balls that are supposed to give more front traction, but I always thought you improve traction by reducing the weight of the suspension components, not by making them heavier!

I would avoid these brass pistons because they're heavy.

The old racer's adage is, "Add lightness".

Anyone have an idea of the physics at play that would make it beneficial to make suspension heavier?

He could probably remove the shocks from the car entirely and still be competitive!

Aside from the "standard" piston that we've seen in kits as far back as the late '80's (RC10, etc.), there are a few aftermarket pistons trying to take our scaled shocks to a higher performance level. Fioroni has an o-ring sealed piston, that gets extra pressure on it from holes that get exposed on one side. VRP offers their XV2 and 3 pistons for added rebound, as well as their GameChanger piston with dynamic compression damping and added rebound.

Hopefully there is some theory as to why a heavier, brass piston would be of some advantage. If not, at least the rubber o-ring keeps the brass from rubbing up against the inside of the shock body, possibly causing additional wear. As mentioned, Teflon pistons are slippery enough to not cause a lot of wear (if any) to the shock bodies.

I've tried both the VRP and Fioroni pistons with some success. However, I switched cars, going from 16 to 17mm shocks and just couldn't get myself to drop up to $60 on some more after market pistons. The VRP GameChangers are pretty neat in what they do. Yet, most still go pretty fast with the stock pistons. Of the guys that beat me locally, most run the pistons that came with the kit. At least that is what they tell me.