2007 Dodge Charger SRT8: Attempting to Fix the Drone with Dynamat
by Carlos Lago, Road Test Editor on February 24, 2016
The drone can last no longer.
It's so bad in our 2007 Dodge Charger SRT8 that you can't have a conversation. It can be hard to think. It occurs at around 2,500 rpm indicated, which happens to be what the engine turns at normal freeway speeds. The volume is as high as 82 dB, per our decibel meter. That's a little louder than your typical vacuum.
Some in the office have adopted the Niebuhr Workaround, but we wanted a permanent solution.
A stock exhaust would solve it, but finding a used set proved more difficult than we hoped, and a new original equipment exhaust would cost thousands. Keeping with the theme from our Millennial Used Car Project, we wanted to do it on a budget.
Dynamat is a sheet of sound deadening material and adhesive often used for insulating interiors from creaks, rattles, and other unwanted noises. The product is marketed specifically towards improving subwoofer performance, but its low price and frequent online recommendation make it appealing to your typical owner. We had to test it, but we would approach it as an owner would.
We ordered a Trunk Kit from Amazon.com for $89.89, which includes 20 square feet of material. We also bought the recommended roller install tool for $20.12. You'll also want a box cutter, scrap cardboard, a vacuum, rubbing alcohol, and some rags. From the Make Life Easier Department, a set of plastic panel removal tools help with removing interior fasteners, while a heat gun or a blow dryer makes the material more pliable during install.
In the pantheon of automotive modification and repair, this install falls on the inexpensive side, but it does take some elbow grease. Prepare to spend around a day.
We figured the trunk was the source of the drone, so we started there and removed the carpeting, panels, subwoofer, and battery. We couldn't completely remove the battery box because the wiring harness spiders through the trunk, but we could loosen it up and move it out of the way.
Next comes cleaning. You want to make sure the surface is unsoiled before applying the material, and that means vacuuming out every last bit of dirt and wiping everything down with alcohol.
Then it's time to start applying the Dynamat. It was at this point that Jason Kavanagh said it felt weird installing sound deadening; he's used to removing it as part of the racecar transformation process.
Mocking up where the material goes is vital. You want to cover the most surface area possible, so avoid cutting shapes where possible because that means waste. We targeted the space where the spare tire would go, the shelf in front, and the rear wheel wells. After that, we applied the remaining material wherever possible, using cardboard to cut templates that would fit around more complex shapes.
Dynamat is somewhat forgiving during application. Once the backing comes off, you simply press the adhesive onto the surface. Once it's settled, use the roller tool to smash it over bumps and into dips. A heat gun or blow dryer stretches the material so you can form it better to the surface.
Once you're out of material, take some time to admire your handiwork. You won't see it again after the interior's re-assembled.
The results? I drove for a little bit first and thought the car seemed a little quieter overall. Then the decibel meter came out. It disagreed. From idle to street driving to freeway speeds, the Charger was no quieter than before. The drone remained.
The problem may be beyond the scope of our Dynamat solution, but we're already cooking up other ways to fix it.
Carlos Lago, Road Test Editor @ 77,900 miles