Fourth Gen F-Body Torque Arms

danbrennan · 06-26-2007, 04:01:59 PM

Why did the third and fourth gen f-bodies need torque arms, while our second gen f-bodies didn't? Did the leaf springs in the second gens serve to take the place of the torque arms? If that was true, why doesn't my '72 442, with rear coil springs, also need a torque arm? I'm a little puzzled about what the torque arm does.

ColdBastrd · 06-26-2007, 04:19:58 PM

It controls wheel hop during acceleration. It helps plant the rear tires to the ground in acceleration and braking. Ever put a lot of juice to the stock rear of an old A-body like your 442? Bet that the rear wheel will bounce like crazy. There are kits to improve that now. With leaf springs, the torque is loaded differantly, hence traction bars.

LRoberts73 · 06-26-2007, 04:24:08 PM

The torque arm resists the twisting motion of the rear axle assembly during acceleration and deceleration. You are correct, with a leaf spring rear suspension, the forward portions of the leaf springs act to resist those same movements.

IIRC, a '72 Olds 442 has a four link rear suspension.. two lower trailing arms, and two upper. This configuration does not need a torque arm... the trailing arm geometry is designed to allow the arms to absorb the twisting motion. This is called a 4-link suspension system.

I'm guessing that the fourth gen Camaro does not have upper trailing arms in the rear, (I can't remember exactly how they are set up). So, with two lower arms and a torque link, you have a 3-link suspension. The long trailing arm is needed because the two lower trailing arms alone do not handle the twisting motion sufficiently.

tom3 · 06-26-2007, 05:28:04 PM

I think it has to do with a unibody compared to a full frame car. The older cars with the frame were stout enough to have the upper control arms while the unibody made do with the control arm back to the tranny with only the lower trailing arms. Pretty good setup I've always thought, keeps the wheels planted and the drive angles correct.

Ian76LT · 06-26-2007, 06:47:55 PM

LRoberts73 is right, the third and fourth gen F bodies have two lower control arms and a torque arm.

Wouldabin · 06-26-2007, 07:06:37 PM

they also have a panhard bar (parrallel to the rear) in addition to the torque arm and lower trailing arms.

danbrennan · 06-27-2007, 08:07:45 AM

I completely missed that the Formula doesn't have upper trailing arms. Thinking about the axles trying to wind up, I think I understand now. Thanks.

BigAls87Z28 · 06-27-2007, 09:23:55 AM

Its design comes from the X-Body of the late 70's. Third/4th gens have a Torque arm that attaches from the back of the trans tail shaft to the pass. side of the center diff. Then there are 2 lower control arms, 2 shocks, 2 coils prings, and a panhard bar that locates the rear. This set up was done to enhance the handling of the third gen when it first came out since performance as of 1982 was a little sad. So to boost the brand new for 82 Camaro's performance angle, the handling was turned up. Third gen also uses a strut front end with only one lower control arm, 4th gen uses an SLA with a coil over type shock system, but from the trans back, its still a third gen.

danbrennan · 06-27-2007, 12:33:59 PM

I'd read the back half of the fourth gens was pretty much the same as a third gen, but I never had a third gen F-body, so I didn't know first hand. I remember reading third gens had a strut-type front suspension, and was surprised when I looked at this '95 Formula that they had went back to SLA. Not disappointed, though. Thanks again.

BigAls87Z28 · 06-27-2007, 01:20:38 PM

Odd part is...they are going back to a strut front end for the 5th gen...but a multi link IRS for the back. w00t!

Yeah, third and 4th gens share rear parts. When you look for rear suspension parts, you will see the years going from 82-02.

night rider · 06-27-2007, 04:40:18 PM

Third and 4th gen F body cars has a 3 link suspension with coil springs
Torque arm for the pinion angle and help plant the tires
Lower control arms to locate the housing front to rear.
Pan hard rod to keet rear centered left to right.

The torque arm also acts in away like a traction bar too, limiting the amount of upward rotation of rear on launch

That is a better suspension for handling, and that's what they built the third and 4th gens to do best.. Handle around curves.

The older coil spring cars was factory 4 link suspension.. With upper and lower control arms to center housing and set pinion angle.

Leaf spring cars like the second gen uses the leafs and spring mounts/perchs to set the pinion angle and center the housing