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Fourth-Gen Firebird Subframe Connector Install - Getting Connected



While installation can be performed using high-quality jackstands, we chose to use a four-post lift, and after raising the Firebird to a suitable height, the first step was to remove the four bolts that secure the underbody crossbrace.
While installation can be performed using high-quality jackstands, we chose to use a four-post lift, and after raising the Firebird to a suitable height, the first step was to remove the four bolts that secure the underbody crossbrace.
SLP's connectors are secured to the body in several locations, one of which is the front bolt of each rear axle control arm. These must be removed during installation.
SLP's connectors are secured to the body in several locations, one of which is the front bolt of each rear axle control arm. These must be removed during installation.
The control arms simply locate the axle, so their retaining bolts should be under little tension during disassembly. With the vehicle supporting its own weight, the control arm should just hang free. Do one side at a time to maintain proper rear axle alignment.
The control arms simply locate the axle, so their retaining bolts should be under little tension during disassembly. With the vehicle supporting its own weight, the control arm should just hang free. Do one side at a time to maintain proper rear axle alignment.
SLP conveniently stamps its subframe connectors with a "D" or "P," signifying driver or passenger side, respectively, reducing the chance of installing the units incorrectly
SLP conveniently stamps its subframe connectors with a "D" or "P," signifying driver or passenger side, respectively, reducing the chance of installing the units incorrectly
We slid this supplied bracket into the rear framerail. A similar piece was inserted into the front framerail, too.
We slid this supplied bracket into the rear framerail. A similar piece was inserted into the front framerail, too.

Starting with the passenger side, we aligned the subframe connector with the control arm and inserted its bolt and nut.
Starting with the passenger side, we aligned the subframe connector with the control arm and inserted its bolt and nut.
Leaving it loosely assembled, we proceeded to thread the supplied bolts into the brackets we previously placed into the framerails. We chose to add a small amount of thread-locker to each supplied bolt to prevent any chance of them working loose in the future.
Leaving it loosely assembled, we proceeded to thread the supplied bolts into the brackets we previously placed into the framerails. We chose to add a small amount of thread-locker to each supplied bolt to prevent any chance of them working loose in the future.
The driver-side connector was installed using a similar process, but the instructions point out that a metal heat shield must be trimmed for clearance. With the connector loosely assembled, we noted the area that required cutting, unbolted the shield, and used a pair of tin snips to remove the marked area. The connector fit perfectly after that.
The driver-side connector was installed using a similar process, but the instructions point out that a metal heat shield must be trimmed for clearance. With the connector loosely assembled, we noted the area that required cutting, unbolted the shield, and used a pair of tin snips to remove the marked area. The connector fit perfectly after that.
With both subframe connectors in place, we attempted to reinstall the underbody crossbrace before securely tightening the mounting bolts, and found that two of the connectors' holes had to be elongated to provide sufficient clearance for the underbody crossbrace's bolts to pass through. It was a minor inconvenience that took just a few seconds to correct with a high-speed grinder.
With both subframe connectors in place, we attempted to reinstall the underbody crossbrace before securely tightening the mounting bolts, and found that two of the connectors' holes had to be elongated to provide sufficient clearance for the underbody crossbrace's bolts to pass through. It was a minor inconvenience that took just a few seconds to correct with a high-speed grinder.
We tightened each mounting bolt until all were snug.
We tightened each mounting bolt until all were snug.
With the vehicle supporting its own weight, the rear control arm nut should be tightened to roughly 60 lb-ft.
With the vehicle supporting its own weight, the rear control arm nut should be tightened to roughly 60 lb-ft.

Most subframe connectors attach at two points, and simply connect the front and rear subframes, but SLP's pieces tie into the underbody brace to further enhance rigidity. With everything assembled, and the connectors securely in place, we were ready to take our Trans Am for a test drive.
Most subframe connectors attach at two points, and simply connect the front and rear subframes, but SLP's pieces tie into the underbody brace to further enhance rigidity. With everything assembled, and the connectors securely in place, we were ready to take our Trans Am for a test drive.
The initial drive has proven just how worthwhile the addition of subframe connectors can be. Our low-mile Trans Am rides noticeably smoother and feels much more rigid. Though our particular Firebird is virtually squeak- and rattle-free, it's no surprise that owners commonly report a decrease of such noises after installation.
The initial drive has proven just how worthwhile the addition of subframe connectors can be. Our low-mile Trans Am rides noticeably smoother and feels much more rigid. Though our particular Firebird is virtually squeak- and rattle-free, it's no surprise that owners commonly report a decrease of such noises after installation.
Though SLP's bolt-on subframe connectors add 45 pounds to a typical Fourth-Gen Firebird, they fit snugly, are well concealed, and are practically invisibly to the untrained eye.
Though SLP's bolt-on subframe connectors add 45 pounds to a typical Fourth-Gen Firebird, they fit snugly, are well concealed, and are practically invisibly to the untrained eye.
For those who are left wondering just how much rigidity subframe connectors can have, consider this picture. With the left rear tire raised the same distance off the pavement before the install, the right rear tire remained flat on the ground. The after effects are apparent.
For those who are left wondering just how much rigidity subframe connectors can have, consider this picture. With the left rear tire raised the same distance off the pavement before the install, the right rear tire remained flat on the ground. The after effects are apparent.
After taking the Trans Am for a test drive, we immediately brought it back in the garage and checked each bolt to ensure all remained tight.  We then brushed black paint over those that were visible.
After taking the Trans Am for a test drive, we immediately brought it back in the garage and checked each bolt to ensure all remained tight. We then brushed black paint over those that were visible.

Conclusion
We found installation to be very straight-forward without any unexpected surprises. Using a four-post lift and normal hand tools, completing the task on our particular Firebird took just over one hour from start to finish. The effects on the subsequent test drive were immediately noticeable-our low-mile Firebird simply felt ighter and dampened road imperfections better, thereby improving the overall ride.

Having dealt with different subframe connectors for various F-bodies over the years, SLP's bolt-on units for Fourth-Gen Firebirds are the easiest we've ever installed, and the effects on ride and rigidity of the structure-regardless of mileage, are spectacular. So if you own a Fourth-Gen Firebird, and haven't yet installed subframe connectors of any type, consider that with an investment of $400 and a couple of hours of installation time, you'll be rewarded with a Firebird that feels tighter and rides better than ever before!


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