Dynomax VT Offers Drone Free Performance Muffler Design

Aftermarket mufflers are often meant to be loud, but while everyone enjoys the deep throaty sound of a well-tuned exhaust system, almost nobody wants to have to deal with drone. Many exhaust installations sound great at idle or under full throttle, but while cruising, they fill the passenger compartment with a dull, booming sound that is louder at certain rpm’s than others. It can make conversation difficult and give you a headache over long trips – in short, drone is the enemy of good exhaust system design.

Cutaway view of the Dynomax VT.

For a long time, car and truck owners have had to accept at least a small amount of drone when pursuing maximum power with an after market exhaust system. Dynomax, however, has come out with what it claims to be a drone-free alternative to high performance mufflers that doesn’t sacrifice engine output in the name of sound deadening.

The Dynomax VT muffler uses a spring loaded in-board valve that opens and closes depending on the amount of exhaust gas flowing through the system. At full throttle, for example, the throttle is wide open. This means that the muffler becomes essentially restriction-free. At idle or regular cruising speeds, the valve remains almost completely closed. There’s just enough room around the valve for the exhaust gas generated at low engine speeds to pass by with minimal restriction.

The valve is spring loaded, and each spring is matched to a specific engine and application. Trucks with dual exhaust systems with dual mufflers, for example, use lower tension springs than trucks with a single muffler exhaust. The spring is manufactured by Tenneco, which is both a Tier 1 auto supplier as well as the parent company of DynoMax. DynoMax warranties the muffler for the lifetime of the vehicle, largely due to the fact that Tenneco makes OEM-quality parts.

A closer look at the valve inside the VT muffler.

4Wheel & Off-Road tested the Dynomax VT on one of its trail Jeeps and were able to see a 6 dB noise drop during highway cruising at 65 miles per hour. They also stated that the Jeep featured far less droning after installing the VT muffler compared to before. The issue with this particular test is that the data gathered really only indicates that the Dynomax VT is quieter than whatever worn-out Brand-X muffler that 4Wheel and Off-Road was using in the first place (the test article was not specific). This is further brought home by the fact that full throttle noise also dropped considerably after the VT was installed.

The Dynomax VT is certainly an intriguing concept, and it is great to see that exhaust companies are actively pursuing drone-reduction technology that has moved beyond the installation of an X or H pipe. If you find yourself being driven up the wall by drone in your vehicle, and you aren’t interested in reconfiguring your pipes until you come up with a drone-reduction solution of your own, then you might want to consider a VT muffler as a possible option. At a price of less than $100 per muffler (depending on application), it’s definitely a cost-effective option.