Buggy Build/Suspension Experiment

[CSR]

Sideways windshield pics. They had small sheets of polycarbonate at the local hardware store, perfect for my needs. I left the middle out to allow some airflow through to the radiator.

Aaand a sideways pic of the oil pressure warning buzzer switch. Tha factory gm oil cooler line block-off casting works great for drilling and tapping a pipe thread hole for the switch to screw in to. I'm using a switch that closes at 20 psi so that the buzzer goes off before I've lost all pressure, and I still have time to shut her down before damage occurs.

Here's a top view where I welded 4 tabs to the top of the chassis in case I need to fab up and attach an aluminum scoop to help air flow to the radiator. If I don't need to do that, I'll fab up a basket that attaches to the tabs where I can carry extra stuff.

My supervisor

Front view with skins


Rear axle view

 

[mbryson]

If the experiment fails, I'll still have a pretty fun crawler. So I don't have much to lose.

agreed, you've got a good setup there and a very interesting experiment. I did think of your down travel observations when I about rolled a golf cart the other day

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If the experiment fails, I'll still have a pretty fun crawler. So I don't have much to lose.

agreed, you've got a good setup there and a very interesting experiment. I did think of your down travel observations when I about rolled a golf cart the other day

 

[TRD]

Very interesting build!!!

You may want to consider more droop travel, it is important for a properly working suspension.

When the axle droops the chassis will lift up to get on top of the whoops.
Allowing the axle to droop into the whoops also allows for lighter compression dampening and reduces harshness.

I had a 2002 Tacoma with Deavers, and incorrect length Fox Smoothies in the rear. They were a badass setup, but when it only have 5/8" droop it drove like a jackhammer.

I'm interested to see how the SUPER high roll center works out. subscribed.

 

[mombobuggy]

It appears that it will set a new standard for stability. Reminds me a lot of the Buggys in Iceland. Gonna be a hill killer.

 

[CSR]

Very interesting build!!!

You may want to consider more droop travel, it is important for a properly working suspension.

When the axle droops the chassis will lift up to get on top of the whoops.
Allowing the axle to droop into the whoops also allows for lighter compression dampening and reduces harshness.

I had a 2002 Tacoma with Deavers, and incorrect length Fox Smoothies in the rear. They were a badass setup, but when it only have 5/8" droop it drove like a jackhammer.

I'm interested to see how the SUPER high roll center works out. subscribed.

I was eyeballing the height of the roll center today, and there's probably room to build in about 4" of droop before the center of gravity passes above the roll center, assuming my driveshaft won't interfere with the chassis with additional down travel. We'll see.

What you're saying makes sense. With no down travel at speed, your tire leaves the ground when it encounters a dip, then impacts on the upside of the dip, giving you the jackhammer ride. Probably better to keep the tire in contact with the ground from the beginning of the dip so that it can rise gradually with the upside of the dip instead of hitting the upside.

 

[CSR]

Looking for feedback on the whole high roll axis idea. I just figured that having a bowling ball on a stick like a lolipop with the stick attached to two horizontal cables and the bowling ball above the two cables is kind of like a rig with a triangulated four link suspension with the upper links mounted underneath the engine/body/chassis. It's going to roll side to side with cornering inertia and sidehill gravity. Why not put the bowling ball between the upper and lower cables where now you just have purely lateral force on cornering and sidehilling, without the arcing roll motion. This keeps your rig's sprung weight horizontal when acted upon by its own inertia and gravity, but the axles can still flex out when acted upon by ground force such as rocks and ruts while crawling.

 

[I Lean]

You are right that the slow-speed stuff should feel very stable. It won't necessarily BE any more stable than another buggy as far as rollover point, since that tipping point occurs when the COG moves outside the tires, not when the body roll starts to make you feel uncomfortable. (of course, your super-wide track and low stance will help you there)

Going fast is where the high roll center might hurt you. In straight bumps you'll be good, but any alternating bumps or twisty stuff, you'll get bucked around side-to-side pretty good. Since the axles need to "swing" a lot to articulate, that translates to kicking you when you hit something hard with one wheel. (does that make sense? Hard to describe in type)

Desert racers used to have extremely LOW roll centers on the front axle because of this. (before IFS became king) A low roll center allows the axle to follow the terrain much more easily, without making the chassis move around a lot.

 

[CSR]

You are right that the slow-speed stuff should feel very stable. It won't necessarily BE any more stable than another buggy as far as rollover point, since that tipping point occurs when the COG moves outside the tires, not when the body roll starts to make you feel uncomfortable. (of course, your super-wide track and low stance will help you there)

Going fast is where the high roll center might hurt you. In straight bumps you'll be good, but any alternating bumps or twisty stuff, you'll get bucked around side-to-side pretty good. Since the axles need to "swing" a lot to articulate, that translates to kicking you when you hit something hard with one wheel. (does that make sense? Hard to describe in type)

Desert racers used to have extremely LOW roll centers on the front axle because of this. (before IFS became king) A low roll center allows the axle to follow the terrain much more easily, without making the chassis move around a lot.

Makes sense. I do have a good deal more swing left to right with the high roll center, which will kick the rig left and right through the uneven stuff.

 

[TRD]

I don't think you're going to experience and adverse handling when the cg raises above the roll axis, the roll moment will still be VERY small compared to the roll resistance from the shocks and springs. Changes in handling will probably not be noticeable.

I Lean also has some good points.

Having body roll may not a bad thing either, it causes weight transfer which can help with cornering.

This is going to be a great learning experience!

 

[CSR]

I don't think you're going to experience and adverse handling when the cg raises above the roll axis, the roll moment will still be VERY small compared to the roll resistance from the shocks and springs. Changes in handling will probably not be noticeable.

I Lean also has some good points.

Having body roll may not a bad thing either, it causes weight transfer which can help with cornering.

This is going to be a great learning experience!

This weight transfer resulting in more traction on the outside tires during turns is what concerns me. While it increases outside tire traction and thereby improves the "crispness" of the turn, I've seen short course situations where guys try a hard corner, the body rolls, weight transfers, outside tires grip, and the rig flips over. I would rather have a rig with a tendency to drift rather than to catch traction and roll, even though quick cornering ability is compromised. I figured a high roll center would help with this. Thoughts? This is all very good info for me and probably several other readers.

 

[TRD]

This weight transfer resulting in more traction on the outside tires during turns is what concerns me. While it increases outside tire traction and thereby improves the "crispness" of the turn, I've seen short course situations where guys try a hard corner, the body rolls, weight transfers, outside tires grip, and the rig flips over. I would rather have a rig with a tendency to drift rather than to catch traction and roll, even though quick cornering ability is compromised. I figured a high roll center would help with this. Thoughts? This is all very good info for me and probably several other readers.

I'm just interested to see how it works. My old Toyota had a high roll center, but not anywhere near as high as this. Your theory might be right, we probably won't know the real story until you take it out.

 

[CSR]

I'm just interested to see how it works. My old Toyota had a high roll center, but not anywhere near as high as this. Your theory might be right, we probably won't know the real story until you take it out.

Even if the speed thing doesn't work out, I still like having the upper links where they are because they are totally out of the way of my up travel, whereas upper links normally start hitting stuff when they come up too far. This whole up travel thing still allows for soft springs without bottoming out even if it is only at moderate speed through mild whoopty dos. It also allows me to have a low-slung vehicle without riding two inches away from bottoming out on a set of air shocks (e.g. my last buggy).

The info you experienced guys have provided all makes sense. I just have to touch the stove myself to know it's hot. Despite issues at speed that I now foresee with my newly-acquired knowledge, I think that some of the ride characteristics will be pretty nice.

 

[zukijames]

is this thing done yet I need to see video of it hauling butt!

 

[mbryson]

is this thing done yet I need to see video of it hauling butt!

 

[CSR]

is this thing done yet I need to see video of it hauling butt!

Almost. But "Almost" with a family and work and a baby due shortly could mean another month.

Front ring and pinion went in today. Just need a pcm reprogram and driveshafts and she should leave the shop for the first time.

 

[zukijames]

sweet the anticipation is killing me! I was going through old pics on this computer the other day and found a couple of the dragon fly from the half hour we wheeled together on Minor threat once haha

 

[CSR]

sweet the anticipation is killing me! I was going through old pics on this computer the other day and found a couple of the dragon fly from the half hour we wheeled together on Minor threat once haha

I remember that day. The Dragonfly was a lot of fun, but I wanted to step it up a little with this build to be able to go a little faster through the bumps.

My wife has named this one the "Phantom". Somehow the colors remind her of the Phantom of the Opera . Never seen it. She wants a rose airbrushed on the hood. I would be down, but it would be extra cost .

 

[zukijames]

buuuump!