Thread: Home brew shocks?

I may try my hand at building myself a pair or two of bypasses. My main question is piston design. Can I simply scale up a 2.5" piston to the diameter I want, keeping the ratio of open and closed surface area the same? If not, can anyone guide me in the right direction? Will probably be making 4.0 or 4.5" dia. shocks if it matters.

you need to find the percentage of flow and duplicate it per the percentage you are in larging it. or something along those lines. the port sizes and and such need to increase somewhere near the same as the increase in diameter

Ok that's what I was looking for. Seems like the logical answer because if a 4.0 only flowed as much as a 2.5 it would have a huge amount of "closed" surface area and would be way stiffer.

same thing happened to multiple shock companies when they went to 3.0 and even 4.0

Originally Posted by NODNARB

I may try my hand at building myself a pair or two of bypasses. My main question is piston design. Can I simply scale up a 2.5" piston to the diameter I want, keeping the ratio of open and closed surface area the same? If not, can anyone guide me in the right direction? Will probably be making 4.0 or 4.5" dia. shocks if it matters.

I'm a bit late with this answer...
That's not really gonna work like you think it will. I'de first look into the largest commonly available shims you can get and design the piston ports around those. If you make a giant piston with ports all across the surface...what do you do if you can't get shims to cover the ports?
Since the goal is a bypass.... it's not going to be a big deal to have less port surface area than the ratio you are thinking of, as the bypass tubes will be there as well.

What he said^^^^^^ Also, if your port openings are too large the shim will deflect into them causing lots of problems..........

Oh snap! Brandon is stepping it up!

Originally Posted by 02dangeranger2wd

Oh snap! Brandon is opening up a whole can of worms!

Fixed........

The CNC lab at the college I went to is sponsored by Mastercam, Ever year they put on an "Innovator of the Future" Contest, they would tell you what you were to make and you had to design and machine it. When I was there my second year we done 1/4 scale shocks for Pablo Huffaker. That was a cool time, it really isnt all that hard to do, you just have to have attention to detail for them to work the way you think theyre going to. They arent bypasses by any means but if you set to it, you can really get creative.

What was the reasoning behind the tapered reservoir body?

They were built more towards eye candy than functionality. When they rated it on functionality, they just checked to make sure it worked right, not that it served its purpose in the long run

last i talked to brandon about this, he was most likely going to make them a solid piston. not gonna be pretty, but function > form.

Hopefully he just ports the pistons instead of trying to run a 3.5-4.0" solid piston. I think he would be much happier with the results.

Solid piston....... Here comes that can of worms........

"It will never work"

better put A LOT of tubes on them..


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He has like 6 valves, I think 4 comp/ rebound and 2 gold valves

Originally Posted by doyouquaxu

He has like 6 valves, I think 4 comp/ rebound and 2 gold valves

that won't be enough...


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I thought this thread had died, thanks for the responses so far, I do still plan on doing this, because it's the only way I can afford big boy parts. I can machine each piece as I can afford it instead of buying all at once. Not planning on solid pistons anymore though.
Plus, I'm really pretty dense and have to learn lessons the hard way. It's not always more fun, but it is more interesting that way.
I'm going into this knowing it'll probably cost more in the long run and make me bang my head against the wall a lot, and I'm ok with that.

Ok, so I'll be using 2.75" shim diameter. Making pistons with an angled top.
Flow will always be restricted to the smallest part of a port, correct?
What I mean is, say the port starts at .500" and then opens up into a .625" at the end, it will act as if it has a .500" port all the way through, correct?
Thanks for any replies.

Originally Posted by NODNARB

Ok, so I'll be using 2.75" shim diameter. Making pistons with an angled top.
Flow will always be restricted to the smallest part of a port, correct?
What I mean is, say the port starts at .500" and then opens up into a .625" at the end, it will act as if it has a .500" port all the way through, correct?
Thanks for any replies.

As I still have a lot to learn, why would you do it that way? Does it kind of act as a funnel effect?

Originally Posted by 04yfzkid

As I still have a lot to learn, why would you do it that way? Does it kind of act as a funnel effect?

I don't think it does, flow should be limited by the smallest part of the port, like a bitchen exhaust system behind shitty exh. Manifolds.

Have to enlarge some parts of the ports to
Clear the shims to allow flow on rebound.

Shocks have always been on my list of things to build, just to say I did. My plan was to start with some off the shelf pistons and go from there. I will never know enough about fluid dynamics to build a better piston than King will sell me for a price that's considerably lower than having it machined to my specs. Considering the deals I've gotten on shocks, it definitely wouldn't be cheaper to build my own, but it would be fun.

if you want a shock to last roller burnish the cylinder its cheap and cuts out all the friction and make the cylinder as smooth as if you where to gun drill it i do this on all my cylinders i build and its cheap
every shock i have ever seen is a joke inside the tolerances are a joke i to have thought about building some that where adjustable from in the cab all manually no electronics i have come cool sure seal valves i build for another industry i sell to that would work great and could have 12 different settings from in the cab

I don't understand what you wrote.

I think FOA (possibly RadFlo) already made some driver adjustable shocks for the KOH guys.

Originally Posted by TRD SRP

if you want a shock to last roller burnish the cylinder its cheap and cuts out all the friction and make the cylinder as smooth as if you where to gun drill it i do this on all my cylinders i build and its cheap
every shock i have ever seen is a joke inside the tolerances are a joke i to have thought about building some that where adjustable from in the cab all manually no electronics i have come cool sure seal valves i build for another industry i sell to that would work great and could have 12 different settings from in the cab

Originally Posted by 2000prerunner

I don't understand what you wrote.

It's a type of finishing for the inside of the tube. The tools has what looks like dowel pins around the outside. As it goes through the tube it spins and the rollers slightly compress the surface to the metal leaving a nice smooth hard surface.

You can also buy hydraulic cylinder tubing that is honed. As long as your careful welding these make very nice shock bodies.

Originally Posted by Brandon_Charley

I think FOA (possibly RadFlo) already made some driver adjustable shocks for the KOH guys.

FOA has done it

foa did it way different then the way i have designed it and they cost so much it was not practical bilstein did it about 6 years ago and cost over 20 grand for just two shocks that where electronic controlled

Originally Posted by TRD SRP

foa did it way different then the way i have designed it and they cost so much it was not practical bilstein did it about 6 years ago and cost over 20 grand for just two shocks that where electronic controlled

are you saying your way or FOAs way isnt practical?

foa and bilstein

the FOA ones im referring to arent electronic or cost anywhere neat 20k.

There was a truggy at Laughlin years ago with Kendall bypass's on it. They had a ball valve on one of the tubes to control flow. There was a small Morse cable running from it to a lever in the cockpit. Adjust on the fly.......

From the pictures I saw of the in cab adjustable FOA bypasses, I want to say that's what they did also.

Electric gate valve from home depot
Find a way to ensure it can hold up to the pressure it will see
Profit!

Originally Posted by F1sleepy

From the pictures I saw of the in cab adjustable FOA bypasses, I want to say that's what they did also.

FOAs is cable operated, but not exactly the same.

where are the pictures of the FOAs I would love to see that set up.

Originally Posted by solidus

where are the pictures of the FOAs I would love to see that set up.

Like FOA on facebook, they just posted some pictures the other day. Sorry I'm too lazy to find them for you lol

foa are junk

TRD SRP suck it douche bag!