Dust Buggy

[HYDRODYNAMIC]

Picked up what should be the last of the tube for the buggy or enough to keep me busy through the quarantine if people start hording DOM.
I searched through all the threads on lower link size and ended up choosing DOM 1020 2.5" x 1/4" wall.
For loading I figured the whole weight of the vehicle on one link, when most likely it will be half the weight of the vehicle on one link. Since the rear has a trailing arm, the coilover will be supporting some of the weight when high centered or the bump stops will be taking the bottoming out force off the link in the opposite direction when under compression.

2" x 1/4" = Has a stress of 94,339 PSI with 5K on 40" link
everyone bends this

2" x 1/2" = Has a stress of 68,027 PSI with 5K LBS on 40" link
lasts for some

2.25" x 3/8" = Has a stress of 56,179 PSI with 5K LBS on 40" link
standard for a number of builders, good reports of lasting

2.5" x 1/4" = Has a stress of 55,555 PSI with 5K LBS on 40" link
What Im planning on running with TMR 2.5"OD x 2"ID tube adapters. Also happens that this is the heaviest wall the suppliers stock that has good pricing.

2.625" x 3/8" = Has a stress of 38,461 PSI with 5K LBS on 40" link
TMR trailing arm size

2.5" x 1/2" = Has a stress of 37,593 PSI with 5K LBS on 40" link
Go to for heavyweights, but still hear of rock bouncers bending these

Then there are the full aluminum or aluminum/DOM stuffed links variants and heat treated chromoly. None of which I was excited about using over DOM only.

Again I want to remind people that this is a family trail rig and not a race rig or rock bouncer. I can replace the links in the future if they do bend too much, but I do not want to go super overkill and add on a bunch of unneeded weight.

 

[HYDRODYNAMIC]

Welded on the boat sides. 1.75" x .25" wall. Planning on bolting on 1/2" UHMW skidplates with most likely some aluminum backing plates.

Dual pass with the Furick Jazzy #10 cup and 1/16" rod. Ran the outside/obtuse welds with a short tungsten stick out and then ran the backside/acute welds with a longer stick out to reach and then bridged the gap between the tube and plate with a big fillet.

 

[HYDRODYNAMIC]

Completed all the bottom side welds so I was able to flip it right side up and throw some seats in it to get a feel for how it would be. Im 5',15" 200lbs and can comfortably sit in the back or stretch my legs out in the front. Planning to run a full height rear bench in the back, what is pictured are the 4" plus tall high back comp seats in ballistic nylon that PRP custom made. Last time I was able to take the bulk material to them, hopefully we can redo that for the bench.

 

[HYDRODYNAMIC]

Front at bump with 10.5 belly on 30" tires with 118"WB
7" uptravel with 17.5" belly with 30" tires
7" uptravel with 22.5" belly with 40" tires

Some of the welds were able to make in a single pass on the .120 wall with a tight fit up, others required two passes to add enough filler and make the weld even when filling bigger gaps. When making a dual pass I was able to make a fast hot pass and level out the material so the second pass would go down faster and more even. I can not say one is better than the other but they both have their use.Attachments

 

[HYDRODYNAMIC]

waterhorse said:
I guess it's the small tires, but it looks long. Especially, from the front seats to the front of the car.​

Its an elusion from the camera angle. It also looks like the tail is super long from the rear camera anlge. The side shots dont look so drawn out. It has a 8" longer total wheelbase than the Goatbuilt Ibex 110" WB + 8" = 118" WB total. With the 4L80 and the Ecobox and NP205, there is alot of drive train to drop in and that is a reason for having it longer. Have a look at the Bomber chassis, that car has the front seats set a ways back, it also has alot of leg room.

 

[HYDRODYNAMIC]

Front links and winch are on. All the chassis tubes are welded out. Waiting until the drivetrain is set before putting on the top of the chassis

 

[HYDRODYNAMIC]

Goatbuilt Domex 100 link brackets.
Lower links are 40" center to center x 2.5" x .25 wall DOM with 1.25" x .625" bore Ballistic forged rod ends.
Upper links are 1.75" x .025" wall DOM with .875" x .75" bore FK rod ends with wide .625" bore misalignment spacers.
Tube adapters were dual passed with 1/16" rod.

 

[HYDRODYNAMIC]

The wheels shown are stock 17" x 7.5" with 40mm or 1.57" offset.
I'm planning to run 8.5" wide with 4.5" backspacing.
It is going to be close, the link bracket is up against the pumpkin and 45* steering throws the tires in. If it rubs then so be it.

 

[HYDRODYNAMIC]

Shock Rebuild & Tuning

For the front shocks, the plan is to rebuild the old 2.5" x 10" Fox piggybacks into 14" travel. I have the new shafts and bodies and rebuild seal kit. Planning to heat the old Loctite and with the shafts or bodies in a clamp break everything loose. Change parts and re-Loctite everything.

QUESTION do I use RED permanant Loctite or BLUE removable? Assuming red as it takes heat to break it loose.

QUESTION what valve stack should I run as a base. What I have is not even close for a SA application. Planning for 6" uptravel total including 2" of air bump travel. For now I have springs at 14"#150 and 16"#200



For the rear shocks, the plan is to re-valve only the old 2.5" x 10" Fox piggybacks.

QUESTION what valve stack should I run as a base. The rear links will be a 2:1 ratio on the coilover. Planning for 6" uptravel total including 2" of air bump travel. For now I have springs at 10" #300 and 10"#300

mobil1syn said:
what tooling are you using to remove the shaft and top cap?

red loctite - the good stuff on the top cap and eyelet

front - i anticipate you will need more spring rate
comp - 12s
reb - 8s

rear - 2:1 is a lot of motion ration, 1.6 tends to be the sweet spot
comp - 15s doubling up the 1.8
reb - 1.6-1.35 8s the rest 10s
Click to expand...​

So fronts would be 70C/30R, rears would be 105C/40R based off of Fox chart. What about bleed screws? I believe all of them are in now due to how heavy the old valving was.

For springs I was going off of what Ratz Racing #4821 had on their Ibex four seater, which was 14"x150 over 16"x200 front and 16"x150 over 18"x150 rear mounted on the axle.
From running spring calculations its looks like mine should be closer to 200 and 200 or 200 and 250 for the front. The traded springs I have should be close enough to get me out and running.

I already have the 10" piggy backs from the old buggy as well as the 300 springs. Due to the rear seat location, the shocks are more forward for clearance creating the higher ratio location on the links. Realistically the rear is not going to droop all 14"s past ride height with 6" of up travel so I could try to push the shocks a little further out to make sure all of the shock travel is being used and limit the droop to 10"

2.0:1 is 20" on a 40" link
1.7:1 is 23.5"
1.65:1 is 24.25" At this ratio the 2.5" shock on the link should be equivalent to a 2.0" mounted on the axle. The 10" shock would equal 16.5 at the wheel
1.6:1 is 25"
I see some tuners show the ideal rear ratio as .8 -.6 and don't go past .5
.5 is 20" on a 40" link
.6 is 24"
.8 is 32"

I have some aluminum jaws for the shaft. For the body I plan to put a slug inside of the body so it doesn't crush.

I was planning on using heat to loosen the thread locker.

For thread locker I will have to see what I have. I have a bunch of different ones but will probably go get some new red as what I have might be expired as I don't use red hardly ever. I normally use the blue sticks as it holds onto the threads and makes things easier than the liquid.

 

[HYDRODYNAMIC]

Got the links attached and adjusted so it is now a roller. Got it outside to see what it looks like from a distance.

 

[HYDRODYNAMIC]

The shocks are in the middle of rebuild.
I heated the top caps in increments with a propane torch and gave time for everything to evenly heat up and they would not release until the 500* temp was reached as stated by Loctite. One of the top caps turned brown and the other had shades of brown.
To hold the bodies, I put two of the aluminum shaft guides with a shaft in them into the body and used aluminum V blocks to hold the body in a vice. The body did slip/turn a little in the V blocks until I got to 500*
The eyes released around 350* and did not discolor. I I used a bar in the eye socket so not to scratch the anodizing.
I ordered new top caps as the old ones looked like garbage afterwords.
The pistons are the current low flow design with red oil.
One of the new 14" bodies had light surface rust inside the tube, I scotch brited it lightly by hand and it was still visible. I have a call into Fox to see if they can send out a new one or I can try to scotch brite it with more pressure and probably drill power to see if it cleans up.

Polished the ID of the rusted Fox coilover body with some scotch brites wrapped around a rod powered by a drill. It looked better than new when done. I was told they could have sat on the shelf for awhile and that is where the rust started since they had no coating and or oil inside to protect them. While I could have waited for Fox to warranty them out, I didn't feel like waiting for another month for them since they are slow right now or having to deal with all the phone calls and delayed shipping. It was the same deal on the 9 hole high flow piston. I placed an order with one vendor who was waiting on an order from Fox to fill and it might be 2 weeks then they had to drill out the bleed holes before shipping out. The same vendor also said I could reuse my old wear bands and orings from my old 8 hole piston when I asked if I needed new ones, I didnt think that sounded right so I researched some more and sure enough the wear bands are a different style from 8 hole to 9 hole, I call back to get them on order and notice that the wear bands they quoted are the bronze bypass version, at this point I don't know if they screwed up again or if they use the bypass bands on regular coilovers for some unknown benefit. I found another vendor who has them in stock but I have to drill them out, the factory has halfway drilled locations.

So this is the question how many and what size bleed holes to drill in a 2.5" 9 hole piston:
- .098" x 2 holes, a 3/32" drill is 96% of this size, this was listed by two different vendors, this is also very close in percentage to a 2.0" shock with .070 x 2 holes which also appears to be common
- .052" x 1 hole - this is standard for a factory built Fox bypass shock
- .070" x 1 hole - this was listed for bump stop use?

 

[HYDRODYNAMIC]

sickboyboone said:
Just a question, not talking shit at all. Wouldn’t it be cost effective to sell the shocks and buy new ones? Seems like a lot of work and new parts to convert 10s to 14s​

Selling a used 10" piggyback shock is the tough part. 12" or 14", I wouldn't have a problem. It was probably a wash on cost but I learned how to do a complete tear down, rebuild, revalve, new shim stacks, and added the high flow pistons which I would have to do with a new shock as well. Plus is I have spare shafts and bodies for the rear shocks now.

Rebuilt the 10" coilovers into 14"s. I decided to go with the 2 qty 3/32 bleed holes in the 9 hole piston. I used a drill press to finish drilling out the pre drilled spots on the pistons. Everything got new seals and oil. To fill the piggyback with oil and set the floating piston height. I filled the reservoir with oil all the way to the top and then pushed in the floating piston and bleed out just a little air and oil until it sealed just like you would do with the rod guide. Then pushed down the floating piston to the height of 9" with a 11" reservoir. The valve stack and 9 hole piston was shorter so I added some more washers / bushings to take up space on the shaft so the nut would be located on the threads correctly.

 

[HYDRODYNAMIC]

Front coilovers and bumps are installed. The lower shock tabs needed to be clearanced a little as the axle swings it needs some misalignment so the eye doesn't bind up.
Rear bumps are in. Used the Wide Open Designs bump cans and mounting plates. They have a offset design so it drops the bump either lower or higher off the horizontal tube. Added some 3" x 3" x 3/4" strike plates, they are welded all the way around, it just looks like only the sides are welded.Attachments

 

[HYDRODYNAMIC]

waterhorse said:
Looks good! God I love that steering. I wonder how high that's going to be when you have the big rubber on it? Looks like maybe 9"-10" more than the bottom of the diff.​

I will need all that clearance since I'm used to plowing through the rocks. It will be a learning curve driving a regular buggy.

The Unknown said:
I keep coming back to check this out and man am I loving the cleanliness of everything. Please tell me this is getting clear coated. What are you using to clean up the tubing? I've been hitting mine with some foam backed 120 grit pads and it is a TON of work and I am only cleaning up the weld joints haha.​

Some of the DOM is smooth and no scale, looks like cold rolled, and only needs scotch brite and degreaser. Some looks like hot rolled with alot of scale and needs scotch brite and or an abrasive woven / composite wheel on an angle grinder. For the weld prep on the ends or middle or I use a 24" strip of 2" wide emery cloth and run it back and forth like a shoe shine.

The Unknown said:
Thank you. Most of the stuff I have needs a decent degreasing and the scale removed. I'll take a look and see if I can find one of the wheels you mentioned.​

https://www.unitedabrasives.com/cate...trip-products/

https://www.amazon.com/United-Abrasi.../dp/B005VS5Q3W

 

[HYDRODYNAMIC]

Rear trailing arm coilover mock up. I wandered from the original cad design and freehand fit the coilovers and the tubes to get as much motion ratio as possible while clearing the seats with enough room to prevent rubbing on the frame and safe clearance away from the seats. I will most likely have a shield of some sort between the coilover and the seat so someones fingers or toes can not end up in the coils. The front end of the seat will be raised up higher and seat inclined so the clearance will only increase.

 

[HYDRODYNAMIC]

The front still had a little more to go, but the rear tire was lifting.

 

[HYDRODYNAMIC]

17" of vertical link travel with a 10" coilover equals .59 motion ratio with .6-.8 being the target range for trailing arm motion ratio.

 

[Firstram]

As much as you got done today, we'll be expecting a shakedown video on Monday!

 

[Lilyota]

As much as you got done today, we'll be expecting a shakedown video on Monday!

 

[Dethmachinefab]

Nice work. I enjoyed the hydraulic buggy thread and it's nice to see your still at it.

 

[Reckless Aaron]

I'm glad you moved this over here!

 

[dnsfailure]

Yep, glad you moved it over here, had just started following it on the +P site a few weeks back.

 

[McBastard79]

Saw this one over on P. Sweet build so far and awesome welding!

 

[CDA 455 II]

Subscribed!

 

[gt1guy]

Hoping you can clear something up for me. I'm setting up full hydro on my rig for the first time. I was told that on the tire pointing out/ ram extended side, the tierod need to be perfectly straight/inline.


I see in your pic, that it's not perfectly straight. I had always assumed there might be a bit of wiggle room to this thought process. Am I correct in thinking a couple degrees is not going to be the end of the world. Where I'm at right now, my setup would look the same as yours



Thanks for any insight you would be willing to share.

 

[WaterH]

Hoping you can clear something up for me. I'm setting up full hydro on my rig for the first time. I was told that on the tire pointing out/ ram extended side, the tierod need to be perfectly straight/inline.

Obviously when the ram is nearly fully extended, it is at its most venerable position for bending. (Less support from the cylinder) that's the reason for your rule of thumb. In the pic you show, if that ram had to push more, it would be very susceptible to side load. But it's at the end of its travel. If you pull it back just one inch, it probably would be close to dead straight. I can't think that you could get much better than that. If it was dead straight at the end of the travel, it would probably be too much off angle on the way out. I think you'll be fine. But I'll also let hydroD comment. His opinion is worth more than mine here.

 

[HYDRODYNAMIC]

The more steering angle you have the closer the high steer arm rod ends gets to the center line of the axle. I mounted the cylinder as high as possible and as close as possible to the axle center line, the cylinder clevis just clears the top of the diff cover. This allows for the tie rods to be inline as much as possible at full turn. My axle is also wider so the tie rods are longer which reduces the angle. Putting a longer high steer arm on would improve the tie rod angle but would also reduce steering angle. So ideally get the ram as close to the centerline as possible. Set your high steer arm to the correct length to get the degree you want. It’s going to be whatever it is going to be from there.

The cylinder rod size diameter and rod guide design plays a part in supporting the ram as well as using a 8” stroke instead of a 10” stroke to reduce the extended shaft leverage and lengthen the tie rods and then using a shorter high steer arm to achieve the same angle.

There is always the ability to run one or two single ended cylinders or a double ended cylinder on one high steer arm with a common drag link or connect the cylinder to the drag link. Then you run the chance of bending a longer drag link and packaging concerns.

Take into account the root cause of bent cylinder rods. It might be clear that the tie rods are super short and at extreme angles or it could be that the cylinder is down too low and the cylinder rods or tie rods got hit by a rock or tree and side loaded them causing the bend. Hydraulically locking the system in the event of a crash can also put too much force on the system bending things. Having a cross port relief on the cylinder can help reduce the pressure spike and blow off energy to lessen the force on all the steering components.

Since it is on topic, I do not have any Ackerman built into the high steer arms to achieve tighter turning on both wheels at the same time. Ackerman has its place on pavement but I rather go for off-road performance.

 

[gt1guy]

Thank you for that.
Our setups are really worlds apart and I know that. You're building cool stuff on a chassis of your own design, I'm hacking a front half job on a JK. I have a ruffStuff fabricated housing that clears D70 gears in a JRat third, so I can only get the ram so close to axle C/L. I had to add some Ackermann just to kick the steering arm out of the coilover/bypass mount when the wheel is turned in. And, running 12* of caster just raises everything on it's own, limiting how high I'm able to raise the ram.

Right now I have 45* steering, while sill maintaining my 6"-7" goal of up travel, running 45" SXII's. I am locked into a 10" ram to achieve this though. At full extension of the ram, my tie rod is a couple degrees out, not much really. Hense my question, will that be the end of the world?

 

[HYDRODYNAMIC]

As I posted earlier, you got the cylinder as close as possible and it is what it is, there is not much you can adjust to make it better. I am guessing that you will probably scratch and or bent a rod from impact before the wheel force bends the rod. That is why you will see all the elaborate steering ram mounts that stick out and go out to the sides protecting the tie rods from impact. At the same time you will see them hung up or bulldozing rocks with those heavy mounts. Like anythings its a balance of not overdoing the protection of one part only to have another part fail from carrying the extra load. Its easy to be the super heavy weight who has a replacement steering cylinder, axle shafts, alternator, tire, drive line, brake caliper, body armor, sliders, etc and is wrenching all day because he is carrying too much weight VS the guy in a minimal 3000 lbs buggy who is through the trails already and back at camp in his trailer drinking a beer because he didn't have the room to fit a cooler and tent and setup camp at the top of the hill. Deciding what you want to do for fun is the hard part.

 

[HYDRODYNAMIC]

I had been thinking of how to control the Ford NP205 twin sticks as well as the EcoBox 241 high/low. I wanted a clean and ergonomic setup with ideal placement and it had to be reliable. I had thought about air operated as it remote mounts and allows effortless shifting. Patooyee and other had setups using different parts and valve combinations. Some were very specific flip a switch style and pilot operated and kept constant force on the stick and were controlled by air all the time so loss of air could switch position or release force and allow it to pop out. I wanted to use the factory indents as intended to hold position and only use the cylinders to be an extension of my hand when needed and then be free. I am using pancake air cylinders which have a shorter over all length and a wider width but they allows for a shorter overall package when bolted end to end to create a three position air cylinder assembly. I am also using a larger bore for higher force. For controls I went back to what worked well on the HydroDyanmic buggy. Four hand lever valves were used for the air ride and I could play them like a trumpet very easily with my left hand while steering or shifting the trans with my right hand. These would connect to the shifting cylinder with 1/4" line. I thought about solenoid directional control valves with three position electrical switches but remembered one time at the Hammers on a cold morning 19* the air ride solenoid valves froze up and wound not open so I had to pour hot water on them to get them to release. Later I switched to the manual valves to create a more reliable system.
For shifting the front axle: Valves 1 & 2 are pushed up for Low or down for High, for Neutral push 1 up and 2 down or 1 down and 2 up whichever way works
For shifting the rear axle: Valves 3 & 4 are pushed up for Low or down for High, for Neutral push 3 up and 4 down or 3 down and 4 up whichever way works
For shifting the EcoBox: Valve 5 is pushed up for Low or down for High