E-Bodies.org Cuda Challenger Forum

 :rebelflag"           Is there an advantage ie. weight reduction, cost. to using bars rather than springs? I think only Chrysler used them in there cars.  Personally I don't like the design. When I had a 68 Satelite race car in the 70s we couldn't pull it with a tow bar. It wouldn't follow on a turn.   

A coil spring is really just a Torsion bar that is wound. The difference is the coil spring becomes unsprung weight while the torsion bar doesn't. Hence the Torsion bar design is actually superior. Another benefit of the traditional Chrysler Torsion bar setup is that it slightly shifts the CG towards the back of the car as compared to coil springs which have all of their mass centered at the front wheel center. Then there is the fact that ride height is adjustable with a Torsion bar setup whereas the coil springs must be cut or changed to adjust ride height in a coil setup. I'll take Torsion bars any day of the week over coils.

approx 3 things , the torsion bar is just an unbent spring , but it sits lower in the chassis & closer to the middle of the car which is far better for handling , it is easily adustable as well & it is safe to install& remove , the last point is the chassis was never designed for a coil spring or coil over shock design as it places the load on the inner fender not the trans crossmember , so now you need a shock brace over the engine which I realy hate

If the 68 Satellite had stock torsion bars, they probably weren't anywhere near stiff enough for cornering a road race car, ESPECIALLY if a larger heavier "race engine" had been installed into the car.

springs (regardless of whether they're torsion or coil) need to be chosen based on the weight & forces that they're expected to handle.
measured as Spring Rate

A torsion bar has a 1:1 motion ratio, while a coil spring does not.  To get an equal wheel rate, I'd think the coil spring would be heavier, but I haven't weighed them.
The weight of a coil spring is entirely on the front end, while the weight of a torsion bar is mostly behind the front end, so I suppose that could help a little with front to rear weight balance of the car.  (sort of like moving your battery to the trunk would do)

Looks like we all posted the same thing at the same time , there were no replies when I started typing my response !!
I doubt there would be significant weight difference between a T bar & coil as it will take the same thickness of metal to create the spring rate & similar distance to allow for the travel  :alan2cents:

You mentioned cost.
I'm not sure how the manufacturing cost would compare, but if you have a Mopar that's already designed for torsion bars, then installing a good torsion bar setup will be MUCH cheaper than buying a kit to convert the car to coils.

   Thanks guys. I still tend to think they were used for lower cost. I mean the average guy buying a Chrysler didn't care about ride height adjustabilty, weight transfer, etc. And they didn't care about handling. 99 % bought a car to get to work, get the groceries, etc.  Now the muscle car guys did, but that was a small percentage of buyers. Food for thought.   :rebelflag"

Chrysler engineers were at the top of the game , the customer may not have appreciated the difference but the engineers made sure it was the best .
Once Mopar quit using T bars Chev trucks & other started using them a lot , Vw bugs used them for decades

 Or not   :haha:   Look at advantages/disadvantages.   https://en.wikipedia.org/wiki/Torsion_bar_suspension

Variable spring is not hard to achive , just taper the bar diameter as you would with a coil

 :rebelflag"    This is an excellent article on the subject.    https://www.allpar.com/mopar/torsionaire.html

Well that settles it, was thinking coil overs, but keeping it as is with torsion bars

I was thinking of an AlterK setup when I started my project, but I decided to stick with the T-bars. I took into consideration exactly what CP said here, that the car was not built to have the force of the suspension on the inner fenders, I also read a tech article about it (forgot who wrote it now), but in the end I did not wanna make such a major change to my car. I trust that the Chrysler engineers know this stuff better than I do. And the Hotchkiss E-max Challenger runs very well with a stock setup so that was proof enough for me.

When I first bought my car even before it was delivered I had intentions of cutting the front clip off at the firewall and building my own clip. HP2 and Neil talked me out of it . That and when I got the car it was so clean and rust free I just couldn't cut it up. I'm very glad I didn't cut it up and stayed with the stock design.  It was not a cheap but I finally have the handling I'm happy with. I had a few spare parts left over when I was done, trying different things. My set up is not " stock" per say but uses stock parts, basically the front end is very similar to the Chrysler kit car. I get a giggle out of people mindlessly following be into a turn. I usually don't use the brakes and often accelerate (which is the opposite of what it drove like stock)   then giggle when they get to a point and slam on their brakes because they can't drive the same.  Tires make a huge difference too. 99% of the Mopar crowd use BFG T/A 's or worce.... they are horrible tires for handling IMO. ( recycled hockey pucks! LOL)

What tires do you recommend Brad?

Quote from: soundcontrol on October 01, 2017, 09:48:13 AM
What tires do you recommend Brad?

Current tires are Falken Azenis 615K I'm happy with them. Not cheap though.... but you want to play you gotta pay. Not much selection in 15" that's why I went to 18"

http://falkentire.com/tires/passenger-car-tires/azenis-rt615k-tire

I assume this is a question of a modern coil-over suspension in comparison to torsion bars.

Others have hit some pretty key points of this. Similarities between the two systems are their ease of adjustability in ride height and ease of changing spring rates. While the springs themselves are not radially different in weight, many coil over systems are designed to utilize smaller and lighter frames mounting systems and rack and pinion steering, which does drop a lot of weight compared to a recirculating ball steering box. After that things continue to diverge pretty significantly.

Overall, the stock mopar design is very robust and was actually ahead of its time and outperformed nearly everyone one of their contemporaries of the day. Many manufacturers since then have changed over to torsion bar systems because of their benefits of low mass, easy adjustability, and improved geometry. The biggest shortcoming of the mopar design is the conjoined caster/camber relationship. This is the only flaw in an otherwise great set up and there are modern style upper control arms out there that will allow this problem to be easily addressed with improved caster angles without sacrificing camber angles. There is some debate about the mopar rear steer design vs front steer designs and how they push vs pull wheels through their arcs of motion. For most of us, this is a minimal issue that using quality parts can eliminate a lot of problems around.

Speaking of geometry, there is not a significant difference between modern coil-over and classic mopar systems. By contrast, early chevy and ford system had major problems with  positive camber gain, cumbersome spring/control arm interface, and uni-body structure to support them.  A couple of key factors in the mopar design that are found in most modern design are camber gains as the car turns. The outside tire gains negative camber as it compresses and the inside gains positive camber as it unloads. This improves tire contact patch while the body rolls. Mopars also have good ackerman angles, which allows the inside cornering tire to turn at an improved angle compared to the outside to minimize scrub and improve tracking through the turn. Some coil over systems do not have this at all. Mopars also have a reasonable anti-dive formula designed into them that matches many modern designs as well.

The biggest current drawbacks to the mopar torsion bar over coil overs is available rates and cost of those rates. There are only seven to eights different rates available and three, maybe four, decent performance handling rates for torsion bars and those come with a $300+ price tag. By contrast, coil springs are available in 50# increments from 100-1000 and are less than $100 a pair. If you are truly in a competitive environment where rate changes make a difference in winning, then a coil over would be preferred. Back in the day, this was not an issue, but now days it could be. However, for most of us, it is not a problem that needs solving because we don't need a variety of rate changes.  It also is not too troublesome to build a good system by choosing the t-bar/ s-bar front combo and then complimenting with the rear system to match. Leaf springs still have an infinite variety of rates that can be built into them.

 :deadhorse: hello old thread, this seems like a good place to ask about the best recommendation for my 383 cuda suspension to keep her robust and fun cornering. Originally I was thinking about qa1 kmember swap but sounds like sticking with a stock design with adjustable uca, upgraded torsion bars and hw/joints? Hotchkis or pst or? Brads70 what magic stuff are you running? :popcorn:

The QA1 is a stock configuration piece. It is just more rigid. It still utilizes t-bars.
But it sounds like you know what you need to do with the suspension. Larger tbars - at least an inch, adjustable uca's are nice if you can afford them but non adjustable arms with more caster built in like the ones from QA1 are cheaper. Or my preference, the Moog offset bushings with original arms. Only set you back $50. Then add good shocks, and weld in some frame stiffening, a proper alignment...
Then  :burnout:

Quote from: wes473 on August 08, 2020, 01:21:39 AM
:deadhorse: hello old thread, this seems like a good place to ask about the best recommendation for my 383 cuda suspension to keep her robust and fun cornering. Originally I was thinking about qa1 kmember swap but sounds like sticking with a stock design with adjustable uca, upgraded torsion bars and hw/joints? Hotchkis or pst or? Brads70 what magic stuff are you running? :popcorn:

Quote from: dodj on August 08, 2020, 04:59:47 AM
The QA1 is a stock configuration piece. It is just more rigid. It still utilizes t-bars.
But it sounds like you know what you need to do with the suspension. Larger tbars - at least an inch, adjustable uca's are nice if you can afford them but non adjustable arms with more caster built in like the ones from QA1 are cheaper. Or my preference, the Moog offset bushings with original arms. Only set you back $50. Then add good shocks, and weld in some frame stiffening, a proper alignment...
Then  :burnout:

:iagree:
I'd agree with dodj.
I kept the original k frame, just rewelded all the seams and added gussets for the steering box.
Here is what I did.....

https://forum.e-bodies.org/wheels-tires-brakes-suspension-and-steering/12/-using-c-body-spindles-on-an-e-body-and-a-body-lcas-and-viper-calipers/58/

QA1 k frame saves you a lot of welding and gives you more clearance. I welded and reinforced my k frame awhile back long  before the QA1 came out to market. I do not have the know how and skills like Brad to go all out. Just standard mods with bolt on parts upgrade. Car handles great and can out turns many modern cars on the road. Seeing them disappear from your rear view mirrors after a few turns put a smile on your face.

 :cheers: Thanks guys for your knowledgeable input, that just saved me a chunk of $ and a bit of time to get the mods done and driving her.

@7212Mopar (https://forum.e-bodies.org/mlist/7212mopar_441) , I see you have an SRT also. I would like my -70's cars to handle like my 08 SRT Challenger.
How does yours compare?