Exhaust System

The last step in getting the truck driveable was to quiet it down.  Based on my experience with the Yukon, I wanted an exhaust system that was quiet—almost silent—on the highway, but that still let me hear the tone of the engine and how it was responding when driving.  For quiet, GM’s factory exhaust systems can’t be beaten.  However, this usually comes at the expense of good flow.  Plus, most of the systems are too quiet for me.  However, the Silverado SS exhaust system seemed to fit my needs.  GM claims it has a “powerful tone,” but since it is installed on a vehicle that is designed to satisfy a wide range of customers, I had no doubts that it would be sufficiently quiet on the highway.  This exhaust system consists of a muffler with dual 2.75” inlets, and two outputs that combine into a 3.5” tailpipe.  Supposedly only one of the exhaust outlets from the muffler flows gas, the other is merely a resonation chamber.  The 3.5” tailpipe terminates by means of a wide stainless steel tip. 

Forward of the muffler, 2.75” piping leads to dual 3” Magnaflow catalytic converters.  Forward of the converters, I used the exhaust components of a 2500HD truck that was equipped with the 6.0L engine.  This means each engine bank gets its own 3” pipe until it reduces to 2.75” about 3 feet in front of the muffler.  An oxygen sensor is installed in each pipe a few inches behind the manifolds. 

The SS exhaust system is exactly what I was looking for.  It has a nice mellow tone at idle, but the engine’s satisfying exhaust note is obvious when accelerating.  On the highway, the exhaust sound is overcome by road and wind noise.  You can hear the exhaust in this video:

LQ9startup2.wmv (1.8 MB)