The body isn't going up, the rear end is doing down. Without the chain the birdcage would over-rotate and lock it's self in place with the tire under the driver side door.
Just try to imagine the stress on that U-joint, the torque from the engine added to the up and down tilt of the differential all at the same time no wonder they fail occasionally...
Could the coil spring on top of the pumpkin be an air bag (spring) instead? Maybe adjustable air pressure would allow you to set to track/course conditions. Also, when you are at max torque is the drive line too many degrees past optimal? That U joint is getting a hella work out.
They will run 6-7 degrees of angle on the rear…. it helps drive the car with more forward bite. The pull bar/spring is adjustable for track conditions…
Since idk why its designed to do this even though watching this under deceleration is cool but i feel like this is built to keep the car straight down the straightaways and then assist with the counter steer in turns since it looks like it makes the rear end track to the right at full acceleration.
Thats the way It's designed bud. Might think about going to a bushing style pullbar if you consistently drop it like that. Soaks up alot more on/off the bars movement and better bite on dryslick.
Look`s like it is working good. May need more pinion it is going negative angel and looks like the 90/10 brake shock might be extending all the way out and making a solid link, Other than that don`t hear any wheel spin.
ok the bar assembly on top is a pull bar it has two major functions it delays instant torque to the rearend to limit wheel slip and It drastically changes the RC. the shock up there is just like a shock anywhere else it dampens the movement and obviously you can speed it up or slow it down. nice setup in this car nice tall LR spring bet money it's under a 200lb. bird cage looks like it's indexing well. looks a little far to my eye (but I am sure the motion ratios is working and indexing the spring up into the chassis.
Awesome. I am building a car that I am planning to take to the road course and I saw this and am curious about how it would do as a top link for a three link in the rear of the awd I am doing for my 55 Chevy wagon. Anyone ever try it or am I nuts to even try it. I think I will and then we will know for sure. Someone has to break ground right?
The bar that is shaped like a J? It’s a panhard bar. It is what controls the lateral (side to side) movement of the rear end. There is a lot more to it than just that, ESPECIALLY on a dirt car, but that is the basics of it.
@@sinnano77 That was 3 years ago. After studying the geometry of the dirt car I understand it a little better. The 2 upper links are new to me, as is the center(w/yellow spring)unit, as it looks to be lacking hydraulics. It sure keeps the tires planted under acceleration! This car really gives this rear set-up a workout. Great video.
Pretty sure these guys know what they are doing. Also remember the car is almost constantly turning left so the visible side of the axle is going to drop.
They are all set up this way now, so you're wrong, it does "do shit". I'd say you haven't been around dirt mods, the rear suspensions have gotten crazy complex, and in my opinion it's not good for the sport. They may be faster, but they are a lot harder to drive, hence you see a ton of yellow flags for spins. I've known some damn good drivers that couldn't get the hang of the damn things. They have drive shafts that use long output yokes that slide way up into the transmisson, and they paint them white so if it does fly out you can see it and duck. They'd do every one a favor if they just ran rear leaf springs, they are more forgiving for various tracks, and the cars look like cars should look, sliding sideways in the corners.
@@505197 are you kidding me, today's cars are way easier to drive than those pos leaf spring cars. More grip, more feel, more consistency, and it gives the driver more trust. You just need to be smart to set these things up. Today its 70% car 30% driver. Good cars make average drivers look good!
This is why I love dirt track cars. So complex compared to asphalt. I love racing on dirt. It's more art and science than just science.
Noticed the limiting chain on left rear is running out of travel! Got to be taking weight off of that tire?
The body isn't going up, the rear end is doing down. Without the chain the birdcage would over-rotate and lock it's self in place with the tire under the driver side door.
Just try to imagine the stress on that U-joint, the torque from the engine added to the up and down tilt of the differential all at the same time no wonder they fail occasionally...
Could the coil spring on top of the pumpkin be an air bag (spring) instead? Maybe adjustable air pressure would allow you to set to track/course conditions. Also, when you are at max torque is the drive line too many degrees past optimal? That U joint is getting a hella work out.
They will run 6-7 degrees of angle on the rear…. it helps drive the car with more forward bite. The pull bar/spring is adjustable for track conditions…
The bar at the top of the pumpkin is called a pull bar it helps the car settle when you get off the gas
Since idk why its designed to do this even though watching this under deceleration is cool but i feel like this is built to keep the car straight down the straightaways and then assist with the counter steer in turns since it looks like it makes the rear end track to the right at full acceleration.
Larry saw modified rear suspension in action and was confused about why the rear extended during acceleration.
Thats the way It's designed bud. Might think about going to a bushing style pullbar if you consistently drop it like that. Soaks up alot more on/off the bars movement and better bite on dryslick.
Look`s like it is working good. May need more pinion it is going negative angel and looks like the 90/10 brake shock might be extending all the way out and making a solid link, Other than that don`t hear any wheel spin.
what is the spring on top of the pumpkin do? whats it called? trying to learn
what is the spring on top of the pumpkin called and what does it do
ok the bar assembly on top is a pull bar it has two major functions it delays instant torque to the rearend to limit wheel slip and It drastically changes the RC. the shock up there is just like a shock anywhere else it dampens the movement and obviously you can speed it up or slow it down. nice setup in this car nice tall LR spring bet money it's under a 200lb. bird cage looks like it's indexing well. looks a little far to my eye (but I am sure the motion ratios is working and indexing the spring up into the chassis.
Awesome. I am building a car that I am planning to take to the road course and I saw this and am curious about how it would do as a top link for a three link in the rear of the awd I am doing for my 55 Chevy wagon. Anyone ever try it or am I nuts to even try it. I think I will and then we will know for sure. Someone has to break ground right?
Out of curiosity, the bar that runs across from the right in front of the axle - is that for sway or alignment adjustment? Awesome video :)
The bar that is shaped like a J? It’s a panhard bar. It is what controls the lateral (side to side) movement of the rear end. There is a lot more to it than just that, ESPECIALLY on a dirt car, but that is the basics of it.
How the rod-end holding the pan hard bar to the frame doesn't break is beyond me.
You mean to the j-bar mount on the diff?
@@sinnano77 That was 3 years ago. After studying the geometry of the dirt car I understand it a little better. The 2 upper links are new to me, as is the center(w/yellow spring)unit, as it looks to be lacking hydraulics. It sure keeps the tires planted under acceleration! This car really gives this rear set-up a workout. Great video.
think you need a little more heavier spring on the pull bar
hey I don't really know what kinda vehicle this is but it looks like he's hanging it sideways the hole time. what is it?
+Jacob Talbot It's a Dirt track car. Most likely a Dirt Latemodel
+Cregen Brady No it is a UMP modified...
+HuntingandracingNut That's cool. knew it was manufactured chassis. just assumed latemodel.
What does the pinion flange - drive line flange drop at 1:54?
looks like a u bolt
It was dirt, watch the video prior to 1:54 and after 1:54.
Looks like a big ass bolt
What's the point of a differential coil?
Keeps the pinion angle correct. Keeps drive in the car
@@blaydemcdaniel9636 Ok but why not a solid link, like a bar?
NutsandGuts the pinion has to move. A solid bar would stop that from happening
@@blaydemcdaniel9636 Not if the links are hinged
@@blaydemcdaniel9636 I'm not trying to argue with you, I'm just trying to understand why a coil xD
sweet ! bitchin cam too .
that guy has got to be dizzy
All that linkage just to be held up by a chain half the time
why are you people watching this if you dont have a clue
curt barfknecht learning has to start with being clueless
Wow. What an arrogant thing to say?
set up has too much anti squat the rear end lifts a lot when your on the gas. not good
Pretty sure these guys know what they are doing. Also remember the car is almost constantly turning left so the visible side of the axle is going to drop.
They are all set up this way now, so you're wrong, it does "do shit". I'd say you haven't been around dirt mods, the rear suspensions have gotten crazy complex, and in my opinion it's not good for the sport. They may be faster, but they are a lot harder to drive, hence you see a ton of yellow flags for spins. I've known some damn good drivers that couldn't get the hang of the damn things. They have drive shafts that use long output yokes that slide way up into the transmisson, and they paint them white so if it does fly out you can see it and duck. They'd do every one a favor if they just ran rear leaf springs, they are more forgiving for various tracks, and the cars look like cars should look, sliding sideways in the corners.
505197 They wouldn’t do anyone a favor but people on leaf springs already... which is a small percentage.
@@505197 are you kidding me, today's cars are way easier to drive than those pos leaf spring cars. More grip, more feel, more consistency, and it gives the driver more trust. You just need to be smart to set these things up. Today its 70% car 30% driver. Good cars make average drivers look good!
mud buildup is my guess