Exhaust drone j pipe. 1 858 457 1253. The J pipe is actually Helmholtz resonator or oscillator that when placed in line with the drone source cancels attenuates anyway the annoying sound waves. To get rid of drone pipe resonance you need to cancel out those specific pipe resonant frequencies. The J pipe is a helmholtz resonator used to do just that. Im finally happy with the exhaust on my LS Swapped Ford F100.
To do this without using a chambered muffler you can use whats called a Side Branch Resonator. Make the j-pipe diameter a half in less than the rest of your exhaust system. In the end I spoke to Rapid and they agreed to modify the j-pipes to their marriage saver ones which are j pipes with mods. It drastically reduced drone frequency noise.
It is usually between 1400-2000 rpm cruising in 6th gear when afm is not engaged. J-Pipe is a J shaped pipe with one end connected to the main exhaust system and another end closed off. Based on the testing we find out that the resonating frequency of the trunk lid is around 220hz and the exhaust pipe is around 120Hz. Custom J-Pipe is the way to go. The J pipe traps a sound wave that usually goes into the muffler in a chamber where it self-cancels causing reduced cabin noise without increasing exhaust restriction or.
How to calculate tube length Exhaust drone is a problem Ive been dealing with and most of the time people solve it by trying various mufflers resonators and sound deadening until they like the outcome.
When the sound frequencies of the exhaust and engine match a. 1 858 457 1700 Fax. Drone is most noticeable at highway speeds not during acceleration or low-speed driving. I used the Helmholtz calculator to figure out the best length of J-Pipe. How to calculate tube length Exhaust drone is a problem Ive been dealing with and most of the time people solve it by trying various mufflers resonators and sound deadening until they like the outcome.