C6 ZR1 Exhaust System - Pipes In The Fast Lane

He tightens the pipe into place using the tack-welded factory clamp on the crossover pipe. Note: Bockwich tightens the axle pipe into the clamp so that it is not quite snug. He'll leave it that way and lock in final positioning adjustments later.

He then routes the driver-side Corsa axle pipe over the ZR1's rear axle and slips it into the factory crossover pipe (not shown).

Next, he tightens the Corsa axle pipe to the stock crossover pipe, via the factory-supplied clamp.

Remember the factory vacuum-activated dual-mode exhaust feature? Bockwich installs the supplied vacuum caps to seal off the factory vacuum line. (Additional instructions that come with the Corsa system show how to easily disable the factory dual-mode exhaust's electronics by removing a fuse.)

After sliding the Corsa muffler hangers into the factory rubber isolators, Bockwich slips the passenger-side muffler inlet over the Corsa axle pipe and attaches it loosely to the pipe with a supplied clamp using a 15mm socket (not shown). He repeats the process for the driver side.

Bockwich adjusts the Corsa system for tip rotation and exit length, then "snugs up" the mufflers to the axle pipe. (Note: Corsa recommends that you pay close attention to clearances around the rearend, transmission lines, and frame above the axles.)

He reinstalls the sway bar, loosely at first using sockets...

...and then uses a torque wrench to tighten the fasteners to 50 ft-lb (top) and 70 ft-lb (bottom).

Finally, he makes adjustments so that the muffler tips are in perfect symmetry to each other and the ZR1's rear fascia.

Here's how the tips look after installation. Notice how both the left and right sets of tips are equal distance from the top of the rear-fascia cutout.

With the Corsa system installed, it's down off the lift and back up on the Dynojet for three more pedal-to-the-metal pulls.

Incredibly, the car registers max peak-to-peak increases of 19.11 hp and 12.49 lb-ft of torque, making this one upgrade that more than lives up to its billing.