1969 Chevrolet Nova - Track-Time Torque Arm Install

Installing Speed Tech Performance's three-link rear suspension.

Chris Shelton Jun 8, 2011 0 Comment(s)
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At the last Super Chevy Suspension and Handling Challenge (presented by Nitto Tire), a dark horse of sorts figuratively, and some say literally galloped in. It wasn't the most powerful nor was it the lightest or most compact, but the Speed Tech Performance '69 Nova exceeded everyone's even its handlers' expectations.

The objective of the Challenge was to pit various suspension manufacturers' trophy cars against a '10 Camaro SS in various contests: slalom, skidpad, braking, etc. That Speed Tech's David beat GM's Goliath wasn't exceptional; a number of cars did. That it trounced the Camaro so soundly was. ResurreXion, as its handlers call it, behaved amazingly well in Super Chevy's battery of tests, especially considering its lack of fine tuning before the event.

We finished it on Tuesday night and loaded it into the trailer on Wednesday, Speed Tech's Blake Foster noted. The Nova bore Speed Tech's latest release, an adaptation of the torque-arm rear-suspension design that GM debuted with the '82 F-body. Basically a hybrid of the four-link and ladder bar, it preserves the best of both (the high instant center and anti-squat of a ladder bar and the articulation of a four-link) and dispenses with the worst (the bind and roll oversteer of a ladder bar and the marginal anti-squat properties of a parallel four-bar).

As good as GM's design was, its implementation wasn't flawless. The soft, oversize bushings the General employed helped the cars ride a little softer but deflected dramatically under load. Open-channel stamped arms and links kept costs down, but at a similar road-holding expense as the soft bushings.

Replacement tubular arms and hard-plastic bushings mitigate the deflection but not without consequences. Their near inability to flex causes the suspension to bind as it articulates, effectively altering the spring rate as a consequence. So extreme are the forces that they often loosen the jam nuts that prevent adjusters from rotating and wearing the threads in the arms. Speed Tech addressed these shortcomings in two ways. One is familiar: Thrust-type bearings in the middle of the lower links eliminate the bind otherwise caused by stiff tubing and solid Delrin bushings. Only these bearings aren't what you think; they're actually threaded joints.

Essentially the lower links resemble an oversize bolt and nut. That it was designed to move freely means it has no jam nuts to loosen or parts to wear prematurely when they do. To adjust a link's length, simply unbolt one end, turn it by hand and reinstall. The design's adjustment range exceeds that of a conventional rod end, and its threads' greater root diameter yield a stronger part too. Finally, permanent grease and positive seals ensure years of maintenance-free operation under potentially the most demanding environment of all: daily driving on dusty and wet roads.

How Speed Tech prevented the torque arm from binding is unique as far as we know. A Delrin bushing bolted to the forward end of the arm slides into a tube at the kit's center crossmember. The hardness that prevents the bushing from deflecting under acceleration or deceleration also prevents the suspension from compressing and rebounding if not for its shape. Its torpedo-like profile makes the bushing act like a spherical bearing, a giant one free to move in and out of the crossmember tube as the suspension compresses and rebounds.

Blake Foster and Roger Maniscalco demonstrated this freedom of articulation for this author before they installed the springs for this story. Though they lifted one side of the axle higher than its upper limit, the other side stayed well below its lower limit. This low-bind operation leaves the springs, dampers and anti-roll bars to control movement. Probably the best way to understand the suspension is to see how it mounts in a car. To do that we followed along as Foster and Maniscalco installed the one on the very Nova that proved the design's merit at the Super Chevy event.

Most notable was the kit's non-invasiveness; it requires no floor modifications and will work just as well on a car with stock wheelwells as it will on one with mini tubs. Its installation requires welding, but the extent is limited to two small sections directly over the rear axle that could easily be removed without harming the car's integrity. Though developed and tested on the '68-74 Nova platform, by dint of platform similarities it also fits '67-69 Camaros. Foster forecasts applications for second-generation Camaros and G-body cars within the year. If those designs fulfill the promise made by this one, rest assured more will follow.

Sources

Speed Tech Performance
N/A,
888-467-1625
www.speedtech-performance.com
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