yellow rose
Overnight Sensation
I'll find the book and see how much of it I want to type. Like I said, if I could copy the page, scan it and post it up I would.
Torsion bars
- Thread starter Hallzy
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I'll find the book and see how much of it I want to type. Like I said, if I could copy the page, scan it and post it up I would.
I believe that the book you are referencing is one of the textbooks I had I my Hi-Po drivelines class in college. And you are right, it has a lot of valuable information. I just feel like you are misunderstanding the stored energy part. Light rate springs release their energy through a longer travel, but don't store MORE energy. The weight removed from the front of the car is based only on the power that the car is able to apply to the ground, which would be the same no matter what spring is in it. As soon as either spring is fully extended, the unsprung mass begins working against weight transfer. The lighter rate spring just allows more weight transfer before that happens
yellow rose
Overnight Sensation
Yes. Door Slammers was our textbook for that class
AJ/FormS
68 Formua-S fastback clone 367/A833/GVod/3.55s
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And that is the type of answer my poser was posed to illicit.
The 440 bars will come off the preload almost right away and it will take many strong men to lift the the front end 6 inches, because the bars are unsprung and NOT helping.
Whereas the 6-cylinder bars have lots and lots of preload, so will help to lift the front end for longer perhaps requiring fewer buddies to get the front end up.
My 1.03 bars have very little preload on them. In fact the one side was difficult to install period with perhaps just 1 turn, (it was a long time ago), required to set the low height.
yellow rose
Overnight Sensation
My bad. I'm using stored energy when I should have said POTENTIAL energy.
That was a cursory view of that chapter.
Do you still have the book? If so, are you able to copy that chapter and post in in this thread? In an hour or so I'm going to read the entire chapter again.
It would be nice if you could post it.
I just looked for it a bit, but I believe I loaned it to a buddy as he backhalved and 4-linked his ranger like 10 years ago. I'll see if he still has it
He does still have it! I'll pick it up and get back to ya tomorrow
Yes, the torsion bar behaves like any other spring. But once they're installed into a suspension system, the two suspension systems may not act the same. A torsion bar suspension system does not load the bars in the same way that a coil spring suspension loads the coils. That's why there are different pros/cons to each system.
And yes, you are right about what components work best.
But your understanding of "stored energy" fails basic high school physics. You have no idea what you're talking about with regard to stored energy.
Nope, that's not the right word either.
We get it, you know what parts to put into the suspension to run down the track, that's great. Stop trying to explain why it works, you don't understand it well enough to explain it.
Exactly so!
Again, the word "preload" is being completely misused.
The concept of preload for a coil spring or coilover spring suspension is very different from what happens with a torsion bar suspension. It's not because of the springs acting differently, it's how the suspension loads the springs.
AJ/FormS
68 Formua-S fastback clone 367/A833/GVod/3.55s
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What word would you prefer Blu; Wind-up? Twist? Crank? Screw? Spring? what word Blu?
yellow rose
Overnight Sensation
Yes, the torsion bar behaves like any other spring. But once they're installed into a suspension system, the two suspension systems may not act the same. A torsion bar suspension system does not load the bars in the same way that a coil spring suspension loads the coils. That's why there are different pros/cons to each system.
And yes, you are right about what components work best.
But your understanding of "stored energy" fails basic high school physics. You have no idea what you're talking about with regard to stored energy.
Nope, that's not the right word either.
We get it, you know what parts to put into the suspension to run down the track, that's great. Stop trying to explain why it works, you don't understand it well enough to explain it.
Exactly so!
Again, the word "preload" is being completely misused.
The concept of preload for a coil spring or coilover spring suspension is very different from what happens with a torsion bar suspension. It's not because of the springs acting differently, it's how the suspension loads the springs.
Let Bonnetron post the pages from the Doorslammers book because it is explained better and has some drawings.
The simple fact is you are creating potential energy when the spring rate is lower and uses more preload.
Been doing it for years and it's a fact. I never trusted anything I leaned in HS as the books are corrupt and the teachers have no idea what they teach.
Tomorrow we can discuss it further, once that chapter is published.
yellow rose
Overnight Sensation
Sweeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeet!!!!!!!!!
After 10 years you are lucky to get it back.
Look, preload is a coil spring suspension term. It's how much the springs are loaded when they're installed. Like YR's earlier example, you have a "free height" and an installed height, just like a valve spring right? The preload is the load induced by compressing the spring to its installed height. How much preload is placed on the spring actually changes how the spring behaves in the suspension. It's even easier to understand with a coilover, you can adjust a collar on the coilover to shorten the spring and load it irrespective of the cars weight being on the spring. By changing the installed height you change the properties of how the spring reacts. Just like shimming a set of valve springs.
That doesn't happen with a torsion bar suspension, plain and simple. Can you load the torsion bar before the weight of the car is placed on it? Sure. You turn the adjusters so that the suspension is loading against the bump stops when the suspension is fully extended. But as soon as you place the weight of the car on the springs, that adjustment just becomes a ride height adjustment. There's no change in how the torsion bar reacts, you haven't changed any of it's operating properties.
The torsion bar adjuster loads the torsion bar in exactly the same way as the weight of the car does, and the weight of the car overrides that adjustment. There's no separate preload adjustment that changes the behavior of the torsion bar.
You are not creating potential energy any differently with different sized torsion bars. Bonnetron already explained this better than I did.
I don't expect you to change your mind though, because as you already said you've been suspicious of anyone that's ever tried to teach you anything. Fact is those books and teachers have more knowledge than you ever will, because you're unwilling to learn.
yellow rose
Overnight Sensation
No, I'm willing to learn. What I don't understand is how you think adjusting up a could spring platforms any different than turning the adjuster bolt up on the torsion bar because it isn't. It's EXACTLY the same.
You either shorten the compressed length by rising the adjuster on a coil spring or you do the EXACT same thing with the torsion bar.
It's the EXACT same thing. A spring is a spring is a spring. When you twist a torsion bar, you are doing the same thing as shortening a coil spring. Other wise, you couldn't change ride height with a torsion bar. You can.
So it's the exact same thing. The smaller diameter bar has a lower spring rate that a bigger bar.
Same thing as a coil spring.
I'm afraid this isn't going to help, but here it is haha. Dave uses "preload" to define the extra unspringing travel distance gained by using a lighter spring and then adjusting the spring platform to achieve ride height. Not more energy, but more distance traveled using the same energy.
yellow rose
Overnight Sensation
hangn0ut
Well-Known Member
All I know is you gotta adjust them torsion bars if your drag car pushes to the right or left.
Not if the weight is the same. You can change the bars if you want to, but if the weight is the same then everything else will be the same as before.
Hallzy
Well-Known Member
Thanks that's what I was thinking
Fisher
Old Guy with a Cool car.
I took all the cast iron off of my 383 and put it on a scale I ended up with a savings of 125 lbs off the 383 with aluminum replacements. I am running a set of 340 bars, and the car rides like a dream and handles well for what i am doing. My duster is 3100 lbs with a full tank of gas and a big block, and full factory interior. Without me in it.
No sir, it is NOT the same thing. When you turn the adjusters on the LCA, you do not twist the torsion bar. The adjusting bolt changes the angle of the LCA with respect to the torsion bar hex blade. The torsion bar doesn't move at all, the LCA rotates around the hex blade. The LCA being held at a different angle to the blade changes the ride height, and the load on the torsion bar remains exactly the same. There is no adjustment to add twist to the bar and hold it there independent of the weight of the car on the suspension.
This is totally unlike a coil spring. You change the platform height on the spring to load the spring independently of the weight of the car, and that is what creates preload. You compress the spring with an adjustment that acts independently of the weight of the car. That changes the installed height of the spring, just like a valve spring. That adjustment doesn't exist in a Mopar torsion bar suspension.
It's like trying to say you have to worry about coil bind with a torsion bar. Coil springs can have coil bind. Torsion bars can't. They're both still springs, but that doesn't mean all the same properties apply.
Exactly. The preload terminology is one that is tied directly to the design of a coil spring suspension.
Sure, with a coil over. The torsion bar suspension that is on these cars simply does not have that "preload" adjustment in it's design. The energy is the same, the amount travel is different. Yes, that's still important for getting the chassis to react the way you want in a drag race, but the terminology that you're using is completely incorrect.
ir3333
Well-Known Member
Of coarse it will ride like a dream...that was the intent with cars being under sprung back in the day.
Picking your speed up or having to react to unseen circumstances is where you will get in to trouble and understeer off the road or just lose control.
Same with the old drum brakes.They are fine as long as you are stopping slowly as you come to a stop sign.
Fisher
Old Guy with a Cool car.
The point i was making is that the car is the same weight as it would of been with an all steel small block. It's a 71 duster for God's sake, its not a Porsche. It's the K car of the 70's. Let it go people.
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