Crazy idea

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Agent_Orange

Agent_Orange

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Crazy idea. I like the torsion bar set up on my duster. To the point of saying I don't see the need for a coil front. That being said my mind is focusing on rear suspension now. And I find myself thing, if I don't want/need a coil front end, why replace the leafs with a coil rear??? Now this might sound crazy of me, but does anyone think a rear torsion bar system would be possible? And if possible, would it offer any advantages over leafs or a coil over street lynx style rear.

I'm not saying I would do it, I'm just interested in the discussion.
 
The drawbacks I see are the need for strong anchor points, and exhaust system routing. May need a whole rear structure to house the adjusters.
 
How far have you thought this out. In my minds eye I see all kinds of strange hook ups. Probably a hundred ways to do it, but I'm not sure it's worth it for a car. I could see it working on twin I-beams say on a Ford truck but the back seems difficult. Some geeky engineer could probably pull it off. My '68 Chevelle had rear coils. I kinda liked them. Try it, it might make you wealthy.
 
pretty sure for something like that to work you'd have to use an independent rear. i think porsche's uses and independent rear with a parralell to axle torsion bar
 
I have seen a few asphalt modifieds with torsion bars on all four corners. It is done to attempt to get the weight as low as possible.....most have been replaced with coils.
 
buckshotbishop said:
pretty sure for something like that to work you'd have to use an independent rear. i think porsche's uses and independent rear with a parralell to axle torsion bar
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I would have to disagree, a rear coil over suspension retains a straight axel. Albeit, if an independent rear set up was used, I couldn't imagine doing so without a coil set up.
 
magnumdart said:
How far have you thought this out. In my minds eye I see all kinds of strange hook ups. Probably a hundred ways to do it, but I'm not sure it's worth it for a car. I could see it working on twin I-beams say on a Ford truck but the back seems difficult. Some geeky engineer could probably pull it off. My '68 Chevelle had rear coils. I kinda liked them. Try it, it might make you wealthy.
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Not much at all lol. I'm just trying to think outside the box
 
Agent_Orange said:
I would have to disagree, a rear coil over suspension retains a straight axel. Albeit, if an independent rear set up was used, I couldn't imagine doing so without a coil set up.
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i just cant think of where on a solid axle you get torque except in the center. ohh just figured it out you would have to run a L shaped bar parallel to the axle and have one end secured to the axle and one to the body.

Im having a hard time fully understanding your statement but if you dont believe that an IRS could have torsion bars check the porsche 944 stock set up.
 
Independent rear is a very general term. If you duplicated the Dart's front suspension in the rear, it would be an 'independent rear suspension'.

Sure you could do 2 T-bars in the rear with a live axle (like it has now). But the way that any 'arms' levered off of the T-bar would ride on the axle would involve some some of rollers or sliders, as the T-bar only exerts force in a circle around a point; it works better to have them work on one of the control arm pivots...which move in a circle around a point!

BTW, just to make you think more.....the 'wire' in coil springs actually work in torsion just like a T-bar....think of them as T-bars wrapped in a spiral. The coil's 'wire' does not bend sideways but twists in torsion....cool, hunh?

The neat thing about T-bar sprung suspensions IMO is that the unspring weight can be pretty low if done right. The Chrysler design is not the best example of that. (Not horrid, just not the lightest.)
 
nm9stheham said:
Independent rear is a very general term. If you duplicated the Dart's front suspension in the rear, it would be an 'independent rear suspension'.

Sure you could do 2 T-bars in the rear with a live axle (like it has now). But the way that any 'arms' levered off of the T-bar would ride on the axle would involve some some of rollers or sliders, as the T-bar only exerts force in a circle around a point; it works better to have them work on one of the control arm pivots...which move in a circle around a point!

BTW, just to make you think more.....the 'wire' in coil springs actually work in torsion just like a T-bar....think of them as T-bars wrapped in a spiral. The coil's 'wire' does not bend sideways but twists in torsion....cool, hunh?

The neat thing about T-bar sprung suspensions IMO is that the unspring weight can be pretty low if done right. The Chrysler design is not the best example of that. (Not horrid, just not the lightest.)
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Good anolgy.....did you stay at a Holiday Inn Express recently?.....be honest.
 
The rear engined VWs and early Porsches used a TB rear. These bars were parallel to the axle axis. The problem I see would be getting a TB with a spring rate that would be appropriate for use at the rear.
 
Too impractical. Too much unsprung weight. Compare the weight of a torsion bar compared to a coil spring. Coil springs can also be variable rate, giving you more load carrying ability with less weight & space. Also you would need to have some sort of moving arms to link a solid rear axle assembly to the t-bars. More added weight & parts to take up space. Then there is the lateral stability problem & also fore & aft movement of the axle assembly. How would you control that? By the time you'd be all done a Leaf Spring rear suspension woul be far superior.
 
two t bars parallel to the axle is how i would see this system working. Although, i'm under the impression that a T-bar rear system would not yield any gains in preformance. My comment about the independent rear suspension wasn't worded correct. What i ment to say was if i were to spend the money on an independent rear suspension, I wouldn't use a torsion bar set up. although, a torsion bar IRS would allow east ride hight adjustment
 
the only gain (IMO) T-bars would give is lower center of gravity....and the ends hardly justify the means in this adventure....I'm sure it can be done and if anyone wants to do it.... as Rocky says " go for it"....and please post pictures
 
I could see a way or two to do it, but it would become more and more difficult as the amount of travel went up. If you limit the travel, you make the ride as stiff as a board, but it would become easier. Too little travel and you will have created a go cart. Another possibility would be to use T-bars in conjunction with a light single tapered leaf spring, which could help in alignment and be a backup for a snapped T-bar. I would probably put the bars at 90 degrees to the axles. One of the problems I foresee, but haven't pondered thru is how to limit the twist of the axle which could be problematic.
 
Lonewolf3165 said:
Too impractical. Too much unsprung weight. Compare the weight of a torsion bar compared to a coil spring.
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No, the upsrung weight is the part of the spring weight that moves with the wheel/axle. Roughly half of the weight of a coil spring is unspring weight and more than 50% of a multi-leaf leaf spring is unsprung weight. NONE of the t-bar weight is unsprung wieght, regardless if it through a pivot in an contrl arm (like in the Chrysler front suspension) or in a VW or Porsche arrangment; the T-bar weight in all of those cases is part of the SPRUNG weight.

FORMULA 1 CARS HAVE GONE FROM COILS TO T-BARS TO REDUCE UNSPRUNG WEIGHT. And T bar weight can be made much, much smaller than what we have in Chrysler front ends by using hollow tubes rather than solid bars. As I recall, the VW 't-bars' are hollow tubes for this reason.

Leafs and live axles are pretty much the worst systems around for unsprung wieght ..... fine for drag racing.... poor for any sort of pavement that is not billiard broad flat.
 
HemiDenny said:
Good anolgy.....did you stay at a Holiday Inn Express recently?.....be honest.
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No....LOL... I got to stay in my own bed last night after a week of work on the road...... BTW, I confess.... I am an engineer.... who actually builds stuff.... GASP!
 
Agent_Orange said:
two t bars parallel to the axle is how i would see this system working. Although, i'm under the impression that a T-bar rear system would not yield any gains in preformance. My comment about the independent rear suspension wasn't worded correct. What i ment to say was if i were to spend the money on an independent rear suspension, I wouldn't use a torsion bar set up. although, a torsion bar IRS would allow east ride hight adjustment
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I see where you are going. For anything but billiard flat surfaces, the unsrpung weight of the live axle is dominant....the leafs add to that but by far the large part is in the axle. The T-bars and locating devices (trailing arms, track bar) would have less over all unsprung weight than the leaf spring stacks, but compared to the axle weight, the usprung weight savings would be miniscule.

Coilovers are essentially as easy to use for height adjustment as T-bars, in my expereince with both. (Chrysler front t-bars vs. 2 rally cars with coilovers all around.)

IMO.... focusing on the rear suspension is the right track.
 
I can't drop the feeling the rear suspension is too primitive. I am happy with my front suspension, minus about 300 lbs on the nose. But the rear suspension feels primitive. I can fix the nose weight issue with carbon fiber bumper/hood/fenders. that is easy enough, just need to find the time. I think you are onto something with the unsprung weight of a heave rear end.

has anyone built an IRS for an "A"??? I would assume the frame to support the pig and attatch a arms to would be rather heavy
 
Check out Toyota Supra rear suspensions and drives; they are mounted in their own subframe. Dunno what HP you plan but they can take somewhere in the 300-400 HP range in the Mk IV generation with no problems. These come in 4 generations, I believe, with the latter 2 being the more desirable and the Mk IV rated for the highest HP levels: an earlier, more compact swing arm type was earlier, and a double control arm later type came in the '86 and later MkIII and MkIV Supra's; the later uppper control arms are AL to save weight. You can get lots of gear ratios for the rear diffs. Not sure what the total wheel travel is on this suspension; upgraded rear anti-sway bars are available..... There is a www.celicasupra.com forums where you can learn far more than I could ever tell you.
 
Look at the rear suspension of a 1986 Alpha GTV6 V-6 , unreal suspension , could take major HP INBOARD DISCS AND REAR mounted TRANSMISSION great for weight distribution
53606d1167603027-82-gtv6-restoration-project-alfa-new-di-dion-2.jpg
 
nm9stheham said:
...... BTW, I confess.... I am an engineer.... who actually builds stuff.... GASP!
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stood out like a sore peter.... I bet you build some trick pieces.

me....not so educated...just living hot roddin' 101

Mopar to ya'
Denny
 
Yes...it is a permanent affliction.....LOL...started out as a technician, BTW. No, I just build some standard pieces, fix/work on all my cars and trucks, race some and break stuff, screw up my share of stuff, and try to understand the math and engineering behind what works....But I build rather than just putzing with a silly computer model all the time....getting one's hand dirty makes all the difference in the world... IMO.

Regards....now back to your regularly scheduled thread.
 
jerry6 said:
Look at the rear suspension of a 1986 Alpha GTV6 V-6 , unreal suspension , could take major HP INBOARD DISCS AND REAR mounted TRANSMISSION great for weight distribution
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All good, except that it is from an Alpha! Nifty Z-bar....I would not want to bump a curb a bit sideways with it though..... Gotta wonder about the solid axle aspect vs a true IRS.
 
nm9stheham said:
All good, except that it is from an Alpha! Nifty Z-bar....I would not want to bump a curb a bit sideways with it though..... Gotta wonder about the solid axle aspect vs a true IRS.
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Works really well , in the Alpha , a strong unit , not the typical fragile build quality of Alpha . Surprised me when I saw it live last week .
 
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