Muffler drone is the bane of many car enthusiasts. Hot rods and other high powered vehicles often fall victim to the noise at speeds above 70mph. Dual exhaust systems can be the most irritating since the vehicle is potentially producing twice the drone. The noise occurs when the exhaust from cylinders resonate within portions of the muffler, usually at a high level of RPM. Consumers can opt to either deaden the sound with a variety of products or install a different muffler. Either way, expect to seek help from a professional unless you have extensive automobile knowledge.
Determine if it is actually the muffler that's causing the drone. Note at what RPM you typically hear the noise. Reach this level of RPM in a lower gear and listen for the same sound. If you don't hear it the noise may be coming from something else on the back end of your vehicle such as the trunk or loose wheels.
Install glass packs or a glass pack muffler on the vehicle. Glass packs are filled with fibreglass that are designed to increase engine power and possibly deaden sound; they come built into some mufflers or may be added by a technician.
Replace your dual exhaust with a single exhaust. This may decrease the power of your engine but will also lessen drone in many cases.
Purchase a Dynomax VT muffler to replace your old muffler. According to the company website, the Dynomax is a "high-flow stainless steel performance muffler that controls irritating drone while ensuring maximum performance on a full-range of street applications". Stainless steel mufflers often prevent or lessen the exhaust drone.
Redesign your exhaust system to include an X-pipe or H-pipe, which in theory could lessen the drone or at least change it to a less noticeable tone. Other items like resonators, silencers or stock mufflers are specifically designed to reduce noise pollution but may also affect the car's performance.
Changing the exhaust system or muffler are the two best ways to lessen or eliminate drone. Other options typically don't work as well.
Altering the exhaust system on your vehicle may change performance and void factory or dealer warranties.