Torsion bars

polara71

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I have the front end torn down on one of the Polaras . The torsion bars are out to replace lower control arm bushings. Ive heard many times of guys replacing their torsion bars or upsizing them. Please tell me why I would replace my torsion bars and why I would keep the factory size or install a larger diameter bar.
Since Im down this far should I be considering it ?
 
I'd leave it alone.

The only time I've ever had a torsion bar fail was in a 63 Dodge. It snapped while sitting in the driveway. My kid just happened to be standing next to it, talking to me. He was about 8... Scared the crap out of him. He still laughs about it.

In theory, a stiffer (larger dia) t bar could improve handling by increasing roll stiffness, but the sacrifice would be ride. Since you are increasing the roll stiffness at the front of the car, you could also expect to increase the understeer as you push it harder. You would then have to increase the roll stiffness at the rear of the car to decrease the understeer.

But you really get into handling theory and the springs are really just there to hold the car up and the geometry and sway bars do all the work.

But you unless you're gonna be autocrossing the big Dodge any time soon, I'd leave everything alone.
 
I'd leave it alone.

But you unless you're gonna be autocrossing the big Dodge any time soon, I'd leave everything alone.


Nope, just trying to give her a nice cruising ride and to improve handling as I push this one harder than the others. There are those that say these are the front springs. If you replaced the rears why wouldnt you replace the front and my answer is, I dont know. Hence the question .....:thankyou:
 
What engine do you have, the 383 two barrel bars non A/C are lighter than the 383Factory A/C cars. Look at the number on the back of the bar, it will tell you what they are. The Factory 440 car bars are the stiffest. But if you upgrade the ride could stiffen up.
I Installed 67 Chrysler 440 Bars in my 66 383 car, and it handled much better, with really no noticable change in ride quality.
 
Nope, just trying to give her a nice cruising ride and to improve handling as I push this one harder than the others. There are those that say these are the front springs. If you replaced the rears why wouldnt you replace the front and my answer is, I dont know. Hence the question .....:thankyou:
I guess the reason for straight up replacement would be if they started to sag like leaf springs or coil springs. But if they do sag, all you do is give the adjustment a twist and your ride height is back to normal.
 
What engine do you have, the 383 two barrel bars non A/C are lighter than the 383Factory A/C cars. Look at the number on the back of the bar, it will tell you what they are. The Factory 440 car bars are the stiffest. But if you upgrade the ride could stiffen up.
I Installed 67 Chrysler 440 Bars in my 66 383 car, and it handled much better, with really no noticable change in ride quality.


383 - 4 N code
 
I guess the reason for straight up replacement would be if they started to sag like leaf springs or coil springs. But if they do sag, all you do is give the adjustment a twist and your ride height is back to normal.

Ive always thought this way John but there must be a reason for the aftermarket, what is it?
 
383 - 4 N code
383 four barrel cars have the Factory A/C bars. They are good. The only next choice is a set of 440 Bars due to the extra weight of the 440 engine. almost all Chrysler 440 cars had Factory A/C, so that is about your only choice.
 
For example and only example...............


Firmfeel Mopar Suspension and Steering

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FFI Torsion Bars
All Torsion Bars are made in house, heat treated and powder coated black.
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For customers that want OE torsion bars with correct forge number we offer complete reconditioning.

Click to see an FFI OE T.Bar

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47" bars: Plymouth 1974-78, Dodge 1965-71, 1974-78, Chrysler 1965-1978, Imperial 1974-75
50" bars: Imperial 1967-1973
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1.00 DIA. Stock App. (WR 142)
TBC4410....$385 (44")
TBC4710....$400 (47")

1.06 DIA. HD/Police App. (WR 185)
TBC4420....$385 (44")
TBC4720....$400 (47")

1.12 DIA. HD/Street App. (WR 220)
TBC4430....$400 (44")
TBC4730....$420 (47")

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Where do these fall in the 383 or 440 category?
 
From the FSM for my 70 300.
.960" for the standard bars
.980" for the A/C, HD and HD 440.

To answer your question "why?", there are people that want a stiffer torsion bar/higher spring rate.
 
Stiffens the ride to work in conjunction with bigger/ more agressive sway bar, you would need low profile sticky tires to really take advantage of the big T bars. FWIW I would concentrate on putting the stock sway bar on urethane pillow blocks and urethane bushings on the end links, makes sway bar/anti roll bar act quicker by holding it more secure( urethane does not give as much as rubber) and not give up ride quality.
 
1) Beefier TB's stiffen the ride, and
2) New spring will always be an improvement.

Given you have replaced all rubber parts, and ball joints in the front end, the beefier TB's will do this:
The front end wallows less, and when the front end hits bumps in the tarmac the car feels more stout. As if it had more muscle to wrestle the road. Makes the car feel incredibly strong. But the bigger TB's will also transmit more vibration to your steering wheel. Not much, but some. That was a major design problem with torsion bar suspensions from day one. So it's a give and take situation. Which one do you value more: the original floaty ride, or the ability be in more control of where the car is heading? - I did like my 1.06" FF TB's a lot. But that is just my .02 cents.

However, I would never put old springs into my car. Period. The spring metal creeps under stress. How much, depends on the load, temperature, number of pulsations (cycles), and time i.e. how long the spring has been under load. A fifty year old TB will have less than 80% of it's original spring rate left. No amount of turning the TB bolt will revive what is lost of the spring rate. You will get the front end higher, for a time, but that is all.
If you like the original ride, go with OEM spec bar.

BTW: Chrysler Corp. added the TB diameter in 0,02" increments, as it's the outer surface only that's needed to resist torsional force. In theory you could replace the TB's with hollow tubes of the same outside diameter.

FF TB's have two gaps here that'd need to be filled: they have a 1.00" bar (which is a good replacement for a 440 A/C car, which originally had 0.98" bars), but no 1.02" or 1.04". The 1.06" might just be too much to those who favor the OEM floaty ride.
 
I don't want the floaty ride. I'd like it to be stiffer, not a lot but stiffer. I like it to corner better but I don't want it to feel like I have no spring up front at all.
 
So you're saying even if I replaced my 50 year old bars with the same diameter bars the ride will improve?
 
I don't want the floaty ride. I'd like it to be stiffer, not a lot but stiffer. I like it to corner better but I don't want it to feel like I have no spring up front at all.

I would go up to the stock C body 440 size or an additional .02 if it were me. You already have stiffer rear springs so should balance out. Here's some personal experience with different torsion bars sizes on a given platform. I've driven 68-70 B body 383-2 with .88 (stock), 383-4 with .90 (stock), and 383-4 with .92 (perf axle pg car that came 440/hemi springs front and rear).

The increase of the .92 and rear springs with the same engine (383) over a .90 or .88 was significant enough to be felt very noticeably, feels great, and really makes the car feel much more stable and flatter through turns than lesser spring-ed versions of the same car. At same time the ride is a very smooth firm ride. Not rough at all.

To sum up a small up-size yields very noticeable effects with no downside in my experience.
 
I would go up to the stock C body 440 size or an additional .02 if it were me. You already have stiffer rear springs so should balance out. Here's some personal experience with different torsion bars sizes on a given platform. I've driven 68-70 B body 383-2 with .88 (stock), 383-4 with .90 (stock), and 383-4 with .92 (perf axle pg car that came 440/hemi springs front and rear).

The increase of the .92 and rear springs with the same engine (383) over a .90 or .88 was significant enough to be felt very noticeably, feels great, and really makes the car feel much more stable and flatter through turns than lesser spring-ed versions of the same car. At same time the ride is a very smooth firm ride. Not rough at all.

to sum up a small up-size yields very noticeable effects

Thank you stranger
 
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