Z06 Exhaust Modded

In February Matt and I installed Z06 mufflers on the corvette, the power gains from them are completely minimal, I did it for sound. After driving the car for a few months I was not totally happy with the sound, it was much quieter than I had expected and the tone was more that of a car equipped with header mufflers.

I had read on numerous corvette sites about a Z06 muffler mod and decided to give it a try. Matt and I pulled the mufflers back off the car and I cut them open to modify the loud side of the muffler. The mod is as simple as adding a sleeve to the perforated pipe on the bypass side.

I purchased an 18" piece of 3" diameter exhaust pipe from the local parts store. I then cut it in half and split it along its length on one side, this allowed me to slip it over the perforated pipe and weld it in place.

These pictures are from someone else that had done the mod, I did not take pictures when I did it.

I drove the car for another month with the exhaust modified and I very much like the sound now, it is a much higher pitch with a European exotic car sound to it. The only draw back to it was a slight drone at 1500-1700 rpm, which coincides with the cars 1650 rpm @ 80 mph. Its not a terribly loud drone and does not prevent normal conversation in the car but would probably be annoying over long distances.

To fix this it was time to install some controls for the exhaust.

There are companies that manufacture kits for doing what I needed for around $190.00 which I was not going to spend. After spending some time searching I found a Logisys 12V 15A Remote Control (RM02) relay for $17.99. This is the same relay used in the $190.00 kit.

I connected it to a EVS9 Duralast EGR Vacuum Solenoid for $15.99. This valve is normally closed which means the exhaust is open or loud until the remote is activated. To hook everything else up I had to purchase $8.00 of vacuum hose and an $8.99 brake line that I ran through the passenger side rocker panel.

Other than hooking up the vacuum line to the back of the intake manifold the installation was easy. My plan of having Matty reach between the firewall and intake to hook up the vacuum line failed miserably when I realized his hands are now as big as mine and he cannot reach into smaller spaces.


The mod works flawlessly and when the exhaust valves are closed it is nearly silent with the sewing machine sound from the rockers being far louder. This will make a potential trip I have planned much more pleasant.