1998-2002 Pontiac Firebird - STS Subterranean Turbo System Installation - Part 2

Slip the supplied clamp over the junction of the exhaust pipe and turbine housing pipe, line up the scribe mark, and tighten the clamp with a 91/416-inch box-end wrench. It is recommended that the joint be welded, but not until final system installation is complete. (We will come back and not only weld the exhaust junction, but also provide an extra measure of precaution by welding the Y-pipe to I-pipe junction as well.) Even a minute exhaust leak will cause a reduction in available exhaust to the turbo, thereby potentially reducing boost.

With the turbo housing mounted, connect the 2x3-inch silicone hose to the compressor housing, and install and tighten the two clamps.

Mount the K&N cone air filter to the end of the air inlet pipe and secure it with a clamp.

Trim the oil return hose that you earlier mounted to the proper length and push it onto the bottom drain hole fitting on the turbo. The barbed end and special fitting are a very tight fit.

Before connecting pipe No. 3 to the over-the-axle pipe (pipe No. 2), first get pipe No. 4 in position. Pipe No. 4 runs a good length underneath the driver side of the car and utilizes brackets supplied by STS to tie into the subframe of the F-body. Begin installation of the rear-mounting bracket by removing the 18mm bolt and nut that holds the left rear control arm.

Once removed, slip the subframe connector brackets (1-inch by 31/48-inch bar with two tapped holes) into the subframe tube and position the bracket so that the threads are accessible through the factory holes in the subframe. Move toward the front of the vehicle and put the brackets that will hold the front of pipe No. 4 into the subframe tube.