Re: Interesting torsion bar discovery...
[Re: DrCharles]
#2566353
10/19/18 09:57 AM
10/19/18 09:57 AM
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Joined: Apr 2006
Posts: 4,220 West Plains, MO
DrCharles
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Thanks Jim, you are right. They are both 892, and they are definitely offset differently. It's not hard to correct, just expensive (as usual with our Mopars!) Just want to know if I can run it that way until the budget allows for a new pair. Edited to add: I mean the 892's have an offset, obviously they're not different from each other
Last edited by DrCharles; 10/19/18 08:46 PM.
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Re: Interesting torsion bar discovery...
[Re: AndyF]
#2567041
10/20/18 08:21 PM
10/20/18 08:21 PM
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Joined: Mar 2003
Posts: 18,678 Fresno, CA
Jim_Lusk
I Live Here
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I Live Here
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Fresno, CA
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i always thought that after a certain size, both bars were the same part number ? i don't know ? That is true but it happens at a bigger size than 0.920 which is what the OP has. OP has .870" bars. Not likely to snap one unless it's damaged already.
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Re: Interesting torsion bar discovery...
[Re: DrCharles]
#2567323
10/21/18 03:07 PM
10/21/18 03:07 PM
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Joined: Apr 2006
Posts: 4,220 West Plains, MO
DrCharles
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Thanks for the update, everyone. If I do buy a new pair, what would you recommend? .92 or even larger? I know 1.03 are available but those seem awfully stiff Mostly street, occasional strip. Forget the 90/10 shocks, I think those would be really weird to drive on the street. I'm not planning to go autocrossing, and soon will be installing homemade (2x3 box tubing) welded frame connectors. The big-block A-body is already nose heavy and I eliminated the back seat which probably makes the weight distribution slightly worse.
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Re: Interesting torsion bar discovery...
[Re: DrCharles]
#2567525
10/21/18 11:10 PM
10/21/18 11:10 PM
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Joined: Feb 2010
Posts: 18,493 Granite Bay CA
Kern Dog
Striving for excellence
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Striving for excellence
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Granite Bay CA
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People that are concerned that a 1 inch torsion bar will be too stiff have never driven or been in a car that had them. My 70 Charger has 1.15 bars and rides about as firm as our 2015 Challenger R/T. The torsion bars and leaf springs need to be complimented by the right shocks though. For many years, I had 1 inch T bars and KYB shocks. Now, The car actually rides better and has more control now with bigger T bars and Bilstein shocks. A 383 or 440 A-body needs more spring rate than a 318-340 car. Mopar had soft spring rates back then. Bigger torsion bars are just a part of bringing the ride and handling quality up to modern standards.
Last edited by Frankenduster; 10/21/18 11:11 PM.
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Re: Interesting torsion bar discovery...
[Re: DrCharles]
#2567531
10/21/18 11:16 PM
10/21/18 11:16 PM
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Joined: Apr 2006
Posts: 4,220 West Plains, MO
DrCharles
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Thanks Firm Feel makes a 1 inch bar... PST has 1.03" for an attractive price, but it is not clocked (front and rear hex are not offset) and many people have said their A-body's ride height is too low even with the adjusters all the way in The B-body has a longer bar than an A-body, so I'm not sure exactly what a 1.15" bar would translate to for my car. As with everything else street/strip, it'll be a compromise. I was thinking about .92 bars because I do want some weight transfer on launch. I wonder how much a 1.00 bar would hurt 60' times?
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Re: Interesting torsion bar discovery...
[Re: DrCharles]
#2567651
10/22/18 02:25 AM
10/22/18 02:25 AM
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Joined: Feb 2010
Posts: 18,493 Granite Bay CA
Kern Dog
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Thanks The B-body has a longer bar than an A-body, so I'm not sure exactly what a 1.15" bar would translate to for my car. Well, the B body LCA is actually about 1/2" shorter than the A-body cars so the leverage is slightly less. An A-body with a 37" bar at 1.0" may not be much different than a B-body with the 41" bar.
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Re: Interesting torsion bar discovery...
[Re: Kern Dog]
#2567655
10/22/18 02:35 AM
10/22/18 02:35 AM
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Joined: Dec 2010
Posts: 12,375 SoCal
MuuMuu101
I got lucky at Woodward!
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I got lucky at Woodward!
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Thanks The B-body has a longer bar than an A-body, so I'm not sure exactly what a 1.15" bar would translate to for my car. Well, the B body LCA is actually about 1/2" shorter than the A-body cars so the leverage is slightly less. An A-body with a 37" bar at 1.0" may not be much different than a B-body with the 41" bar. The B body bar will have about 10% more twist in the torsion bar for the same diameter, material property, and torque. phi = 32*L*T/(G*pi*D^4) phi: angle of twist L: Length of bar T: Applied Torque pi: 3.14... G: Shear Modulus of Rigidity D: Diameter of Bar https://www.engineeringtoolbox.com/torsion-shafts-d_947.html
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Re: Interesting torsion bar discovery...
[Re: MuuMuu101]
#2567671
10/22/18 04:12 AM
10/22/18 04:12 AM
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Joined: Feb 2010
Posts: 18,493 Granite Bay CA
Kern Dog
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The B body bar will have about 10% more twist in the torsion bar for the same diameter, material property, and torque.
10% more twist? Do you mean that it is less effective because it twists MORE or more effective because it resists twist 10% more ?
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Re: Interesting torsion bar discovery...
[Re: Kern Dog]
#2567807
10/22/18 01:35 PM
10/22/18 01:35 PM
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Joined: Dec 2010
Posts: 12,375 SoCal
MuuMuu101
I got lucky at Woodward!
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I got lucky at Woodward!
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The B body bar will have about 10% more twist in the torsion bar for the same diameter, material property, and torque.
10% more twist? Do you mean that it is less effective because it twists MORE or more effective because it resists twist 10% more ? Because the B-body T-bar is longer, it is less effective because it twists more.
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Re: Interesting torsion bar discovery...
[Re: DrCharles]
#2568309
10/23/18 12:55 PM
10/23/18 12:55 PM
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Joined: Jan 2003
Posts: 5,386 Pikes Peak Country
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A 1" B body bar is 175# wheel rate. A 1" A body bar is 195# wheel rate. Wheel rates are the springs applied force at the center of the tire's contact patch. This is how you can compare different spring rates and suspension designs to come to an apples to apples comparison of rates.
In my experience, a larger bar gives up an amount of 60' time, however, it will be much more consistent and repeatable than a lighter bar and 90/10 shocks.
My drag car with SS rear, light front end rates, no sway bars, and adjustable drag shocks would run 12.2-12.6 and was variable with track prep and atmospheric conditions. The same driveline in my handling car with heavy t-bars, large front and rear sway bars and much wider tires all around would run 13.2 run after run after run. If you're a bracket racer, you know which one you need to have to win.
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Re: Interesting torsion bar discovery...
[Re: DrCharles]
#2571072
10/29/18 04:37 PM
10/29/18 04:37 PM
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Joined: Jan 2010
Posts: 1,442 NW Chicago suburban area
Mopar Mitch
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NW Chicago suburban area
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I've tried many different sizes of TBs in the Challenger... and some different shocks.. and different leaf springs... for the purpose of competition AX/HSAX... settled with the 1.24 TBs... they are great! Yes stiff, but still drivable on the street and highway... as long as you avoid rough roads (race tracks typically are smooth!). Tire pressures and sidewall aspect ratios matter, as well, so, it becomes a compromise to accept what you've got and learn to drive the car with the setup. A benefit of larger TBs is that they also reduce lift and dive.
Mopar Mitch
"Road racers and autocrossers go in deeper and come out harder!"... and rain never stops us from having fun with our cars... in fact, it makes us better drivers!
Check out MOPAR ACTION MAGAZINE, August 2006 issue for feature article and specs on my autocross T/A!
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