Engineering The Suspension

The Strange Engineering nine-inch Ford housing is packed full with a lightweight spool and 35-spline axles, along with their Pro/Race steel rear brakes. Suspension brackets to fit the Camaro body are installed at the Strange factory before powdercoating.

The factory independent suspension presented a number of challenges for the Chevrolet Performance engineers when developing the COPO package, and to that end they selected Pustelny to do the development work on the chassis to allow the straight-axle housing to fit properly under the car.
“We contracted MPR Race Cars, and Mike built the suspension along the lines of what NHRA approved,” says Chevrolet Performance’s Roger Allen. “We provided MPR with the design direction, and then MPR fabricated the parts to put everything in place. The overall geometry and pickup points had to be as specified by NHRA. They basically gave us suspension pickup points from the Strange axle and said ‘Here’s where the Dodge and Ford pickup points are – yours have to be in the same place.’”
MPR had to reverse-engineer the pickup points from the given locations to fit specifically in the Camaro chassis, which was a challenge given the current independent-rear suspension design and the fact that the platform was never designed to have the solid axle placed underneath. As he had completed the same type of work for Dodge on the Drag Pak Stock Eliminator program, he had a good idea of where to start.
[TABLE]
[TR]
[TD][/TD]
[TD][/TD]
[/TR]
[TR]
[/TR]
[/TABLE]
Left - The COPO Camaro suspension design centers around a set of fixed-length lower control arms and adjustable uppers so that pinion angle can be set for maximum traction. Right - The anti-roll bar is constructed from 1 1/4-inch 4130 chromoly tube and has six-inch arms to connect the links to the rearend.

“The suspension was developed from what we know will work, what we know the NHRA will accept, and what we know will be safe,” explains Pustelny. “Once NHRA looked it over and gave us approval for the design, I drove the test car for the first year. Even the first time out, the car went down the track like it was on a string. It’s no revelation that we could make some changes to make the car work better, but one of the criteria for Stock Eliminator is that you must have a fixed lower control arm, and the brackets on the chassis and rear axle housing cannot have multiple holes – there’s only one position where the bars can be located.”
The Suspension Parts
With the restrictions placed upon the design by NHRA, Chevrolet Performance had a box to work within, and the end result is a four-bar, upper- and lower-control arm design that uses a Panhard bar for lateral location and an antiroll bar for dragstrip performance. The nonadjustable lower bars are constructed from 20 inch-long, TIG-welded 1 3/4-inch .083-wall 4130 chromoly that uses a urethane bushing at each end. Upper control arms are permitted to be adjustable, and to that end MPR developed 1 1/4-inch, .095-wall 4130 chromoly that has a left/right hand tube adapter welded in for pinion-angle adjustment purposes. There is a 3/4-inch x 3/4-inch chromoly rod end at each end of the upper bars. Suspension attachment bolts are 1/2-inch on upper and lower bars – the lower bars use a sleeve within the bushing to achieve this dimension, and the upper bars have machined spacers that sit within the rod end.
The antiroll bar uses an interesting design – a 5/8-inch spherical bearing at each end of the bar is threaded into tubes that are mounted in the chassis. The bar itself is 1 1/4-inch .095-wall 4130 hollow chromoly tube with six-inch arms welded at each end that use aluminum/rod-end links to connect to the rearend housing.
Chevrolet Performance engineered the spherical rod-ends for the antiroll bar to mount topside to the chassis and capture each end of the bar, rather than many traditional bars that mount to the framerails at each end.