Search the Community
Showing results for tags 'drone'.
Found 2 results
Drone is that loud humming noise after you've installed your cool shiny new exhaust system around 1800 - 2200RPM depending on your final drive ratio. It's very annoying for most and will drive your girlfriend (or boyfriend) right out of the car. So what is it? What causes it? What can I do about it? What is it? Drone is the word to describe a resonance phenomenon that offends nearly every type of material on the planet as a specific frequency range. What causes it? This sound frequency range is typically between 133 - 138hz for cars. This frequency sends the energy through the metal frame, body work, and everything in between (even seats in some cases) and shakes the molecules creating an awful humming sound. What can I do about it? Not much. You can't really block this frequency range because it is a natural resonance frequency. It will rattle EVERYTHING (even materials like wood and some softer materials as well). Dynomat in your trunk won't work. Dynomat on your floorboards or on the unibody underneath your seats won't work. This range of 133 - 138hz is incredibly difficult to manage. The best way to address drone is with muffler design or resonators. The factory mufflers are specifically designed to not only block but also CANCEL these frequencies. Some aftermarket designs such as Borla's and Corsa's offerings do the same job. Borla's design cancels out some of these frequencies as well as ensures that the sound energy is going out the tailpipes. Corsa's designs have an internal chamber that is of the correct length to cancel this frequency out using the laws of wave reflection. Designs like the Magnaflow Competition Catback that uses a 5"x14" resonator to attenuate the engine sound drone like a mad cow. Flowmaster American Thunder mufflers drone like crazy because they were designed to produce a specific sound that was focused on the outside of the car. There's nothing wrong with this, it's just what the manufacturers decided to produce. If you have an exhaust system with one of these such designs and don't want to change your entire system, then a set of straigh through race mufflers such as Dynomax Race Bullets or Pypes M80 mufflers will give you some relief but may not completely eliminate the drone depending on your overall setup. What else to take away from this? Remember, exhaust systems are exactly that: systems. They sound, flow, and benefit your engine setup the best when thought of as a whole and variables are taken into consideration under every circumstance.
Guide to Exhaust - System Types - Axle back Position: These simple systems replace all hardware from the axles, back. This system almost always consists of mufflers unless you install a "muffler delete" kit. Power Gains: Virtually none. Popular Offerings Roush Axle back Volume: Super Aggressive Drone: None Sound Description: Loud, aggressive tone. Deep throaty sound in the low RPM range. Raspy and loud mid range and up. Materials: Polished 409 stainless steel open chamber mufflers. 409 stainless steel mandrel bent tubing. 4" T304 stainless steel tips. Borla Touring Volume: Mild Drone: None Sound Description: Tastefully mild, deep gurgly, very throaty sound throughout the entire RPM range. No rasp. Materials: T304 stainless steel chambered mufflers and mandrel bent 2.75" tubing. 4.5" T304 stainless steel tips. Borla S-Type (unofficially known as "Stingers") Volume: Moderate/Aggressive Drone: None Sound Description: Loud throaty rumble. Very deep tone throughout the entire RPM range. No rasp. Highly popular offering. Somewhat similar sound to a 3v 4.6L. Materials: T304 stainless steel chambered mufflers and mandrel bent 2.75" tubing. 4.5" T304 stainless steel tips.