Adjustable stabilizer/sway bar?
11-10-2009, 08:36 PM
#1
Burning Brakes
Thread Starter
Adjustable stabilizer/sway bar?
I'm considering adding a standard 5/8" rear and a 1 1/8" front to mine, and I came across this. Apparently one can get a large sway bar and use the springs to control the torsion stiffness. I would think that would depend on the sway bar itself and not the length of the bolt.
Has this ever been done before?
Has this ever been done before?
11-10-2009, 09:09 PM
#2
Le Mans Master
These have been around for a while. I don't think you really are going to change the torsional stiffness of the bar, as much as you will delay the bar resisting body roll. I guess technically you are adjusting stiffness in programming in a delay.
Of course if you're using poly bushings you may find that the car rolls to a point until the spring collapses (goes into bind) and the bar immediately resists further roll. I have no personal experience with them, but it could cause the car to snap loose abruptly.
I do use a rear sway bar on my '73 with the poly bushings but it resists roll the instant the car begins to turn. You may find that plain old rubber bushings to be a bit more progressive. They will effectively reduce the stiffness of the bar without the abruptness of using the springs.
Give it a try and let us know what you think...
Good luck... GUSTO
Of course if you're using poly bushings you may find that the car rolls to a point until the spring collapses (goes into bind) and the bar immediately resists further roll. I have no personal experience with them, but it could cause the car to snap loose abruptly.
I do use a rear sway bar on my '73 with the poly bushings but it resists roll the instant the car begins to turn. You may find that plain old rubber bushings to be a bit more progressive. They will effectively reduce the stiffness of the bar without the abruptness of using the springs.
Give it a try and let us know what you think...
Good luck... GUSTO
11-10-2009, 10:07 PM
#3
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You're just softening up the rear roll stiffness (as you now effectively have the spring and bar in series during compression), up to the point where the spring hits coil bind, and then the roll stiffness returns to normal. A reasonably stiff spring will just cause the bar to twist/bend also during corner lean, and probably not go into coilbind. Just depends on the relative stiffness of the two spring elements, the free height, and the suspension travel.
11-10-2009, 10:18 PM
#4
Le Mans Master
I have these on front of the '64.
My thought was that the adjustment simply lets you dial in when the bar starts resisting the tortional movement. You've basically got to get the slop out of the spring before the bar becomes effective. The tighter that you crank on the spring, the sooner the slop is taken out and the bar becomes effective. Mine use polygraphite bushings.
My thought was that the adjustment simply lets you dial in when the bar starts resisting the tortional movement. You've basically got to get the slop out of the spring before the bar becomes effective. The tighter that you crank on the spring, the sooner the slop is taken out and the bar becomes effective. Mine use polygraphite bushings.
11-11-2009, 08:28 AM
#5
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. I don't think you really are going to change the torsional stiffness of the bar, as much as you will delay the bar resisting body roll. I guess technically you are adjusting stiffness in programming in a delay.
Of course if you're using poly bushings you may find that the car rolls to a point until the spring collapses (goes into bind) and the bar immediately resists further roll. I have no personal experience with them, but it could cause the car to snap loose abruptly.
Of course if you're using poly bushings you may find that the car rolls to a point until the spring collapses (goes into bind) and the bar immediately resists further roll. I have no personal experience with them, but it could cause the car to snap loose abruptly.
No thank you. I wouldn't put these on my car.
Jim
11-11-2009, 10:30 AM
#7
Burning Brakes
Thread Starter
I agree too. I was not considering using a system like this, just wondering if anyone has done it. I've ordered the standard 5/8" and 1 1/8" bars for my car, but will use them as designed.
FWIW, that spring in the photo is a valve spring that the owner fit into the space and thought it would be cool to try out.
I had my reservations.
FWIW, that spring in the photo is a valve spring that the owner fit into the space and thought it would be cool to try out.
I had my reservations.
11-11-2009, 11:30 AM
#8
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I'm with Jim - you want the bar to provide a constant linear stiffness (rate), not one that suddenly changes during deflection.
11-11-2009, 11:47 AM
#9
Drifting
The "spring" link will be stiff in extension and soft in compression, so the bar will be stiffer in one direction (right or left turn) and softer in the other direction. NASCAR?
11-11-2009, 12:23 PM
#10
Le Mans Master
Guys, guys. Just crank the bolt down on the spring bottoming it out and you take it out of the equation. Take the tension off the spring for drag racing.
11-11-2009, 02:15 PM
#12
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I have these on front of the '64.
My thought was that the adjustment simply lets you dial in when the bar starts resisting the tortional movement. You've basically got to get the slop out of the spring before the bar becomes effective. The tighter that you crank on the spring, the sooner the slop is taken out and the bar becomes effective. Mine use polygraphite bushings.
My thought was that the adjustment simply lets you dial in when the bar starts resisting the tortional movement. You've basically got to get the slop out of the spring before the bar becomes effective. The tighter that you crank on the spring, the sooner the slop is taken out and the bar becomes effective. Mine use polygraphite bushings.
11-11-2009, 03:06 PM
#13
Drifting
Looks to me like he replaced the compression cylinder (far left) with the valve spring...but my vision is going.
Edit: OK..Got it. The picture is before and after, not right and left. Thanks.
Edit: OK..Got it. The picture is before and after, not right and left. Thanks.
Last edited by mashinter; 11-12-2009 at 06:43 AM. Reason: lightbulb came on
11-11-2009, 03:14 PM
#14
Le Mans Master
No, no, no. As soon as the spring starts to compress, the force will also try (and succeed!) to twist the sway bar. As I said before, the spring/torsion bar elements are in series. The force goes through both of them. The amount of each deflection is just a matter of the relative stiffness of the spring and bar.
But for drag racing, you don't want a front bar. So let the springs loose and you've taken the bar out of the equation for straight line accelleration.
11-11-2009, 09:56 PM
#15
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Yes, yes, yes. As soon as you crank the bolt to bottom out the spring, What is the point of putting the spring in, only to bottom it out??? it becomes rigid like an ordinary sway bar as if there were no adjustability. Are you implying that everyone with an ordinary-type sway bar is doing it wrong? We're not discussing ordinary sway bar link systems. We're discussing someone putting a spring in the link, and the effects of two spring/torsion elements in series.
But for drag racing, you don't want a front bar. So let the springs loose and you've taken the bar out of the equation As long as the springs are in there, and not collapsed, the bar is not out of the equation. for straight line accelleration.
But for drag racing, you don't want a front bar. So let the springs loose and you've taken the bar out of the equation As long as the springs are in there, and not collapsed, the bar is not out of the equation. for straight line accelleration.
JMO
11-11-2009, 10:18 PM
#16
Burning Brakes
Thread Starter
Yes, the springs would go on both sides. The photo was when they just had the one side for comparison purposes. And, yes, they are just everyday standard valve springs from some old heads they had. They thought it was just a cool idea and suggested it to me since I'm adding sway bars soon, but I'm foregoing the system at this point.
I thought people were kidding that this actually exists, but I see that they're out there! To each his own. I was just curious, and thanks for all the replies. Isn't technology grand?
I thought people were kidding that this actually exists, but I see that they're out there! To each his own. I was just curious, and thanks for all the replies. Isn't technology grand?
11-11-2009, 10:43 PM
#17
Le Mans Master
I don't do the straightline stuff, but it's always amazed me when guys unhook/remove the front bar. It seems a dangerous thing to do in the case where the car gets sideways during the run, and steering corrections are made. The shift to the rear of the vehicle roll stiffness would increase the likelihood of the vehicle spinning out.
JMO
JMO
Thinking and planning for something to go wrong when it hurts ET and is not mandated is defeatest and doesn't win races.
11-11-2009, 10:50 PM
#18
Le Mans Master
Yes, the springs would go on both sides. The photo was when they just had the one side for comparison purposes. And, yes, they are just everyday standard valve springs from some old heads they had. They thought it was just a cool idea and suggested it to me since I'm adding sway bars soon, but I'm foregoing the system at this point.
I thought people were kidding that this actually exists, but I see that they're out there! To each his own. I was just curious, and thanks for all the replies. Isn't technology grand?
I thought people were kidding that this actually exists, but I see that they're out there! To each his own. I was just curious, and thanks for all the replies. Isn't technology grand?
Only one spring per side (one on drivers side and one on passenger side). The opening picture is a complete unit for either side and the spring replaces the sleeve. Actually, I think there is also a sleeve inside.
It's definitely NOT a valve spring. It's much longer, thinner and weaker.
If you think about it, a sway bar is a crutch to band aid body roll. You want an independant suspension such that bumps on one side of the road/car don't effect the suspension on the other side and a sway bar takes some of this away by tieing the two sides together at the lower A-arms. The sway bar end-link spring basically decouples the bar from the lower A-arm until the spring bottoms out. Originally this is done with a rubber bushing. But firmer bushings hold the bar tighter and as a result you loose a degree of the suspension's independance and pick up harshness, especially when one side get in the marbles.
The spring then let you set a level of independance such that one side of the suspension ignores the other until the spring bottoms. This smooths out road bumps and such. But if you go into any kind of a real turn that causes the suspension to collapse, the spring instantly bottoms giving full sway bar support.
Last edited by toddalin; 11-12-2009 at 01:01 AM.
