looking for No Drone Exhaust
Senior Member
Joined: Jul 2005
Posts: 575
Likes: 0
From: Oronoco, MN
When people say "I've got xxxxxx system and no drone" you really need to add if you've got anything else done, and what year of truck. The '03 and down trucks are very different from the new style as far as body structure, frame, insulating material, etc.... and will NOT have the same results from each brand. Any other changes like headers or high flow cats will also make a huge difference.
As far as turbos being the only source....no, no and no.
As the thread has shown its hard to describe, but "drone" is a resonance inside the cab, not sound (loud or otherwise) coming from outside. Every structure, including our truck bodies, has a "resonant frequency" where the structure will pick up and amplify a sound frequency. A lot of aftermarket exhausts hit the resonant frequency of the body when the engine is around 1800-2400 rpm, and depending on the design and volume of the system the drone can range from noticable to extremely bothersome. I've been in Mustangs that could give you a headache cruising at those rpms the resonance was so bad. Anyway, how do you avoid it? A quality exhaust company will work to reduce or eliminate sound in the frequency range that resonates in the vehicle, others just slap the same muffler style in every kit. Feedback from other users is the best way to determine which company did the job well, but as mentioned above make sure you are comparing similar vehicles. I'm a little stuck myself as I have longtubes and high flow cats and not many people have that setup so feedback is limited. I have a single 3" Flowmaster catback that was on the truck when I bought it, had zero drone when the headers and cats were stock but has quite a bit now. Currently I have some weights strapped to the long pipe in front of the muffler in an experiment to change the frequency of the vibration, it made a noticable difference in the drone level but I think a lot of it is also coming right from the muffler body. I have one more experiment to try and alter the frequency, otherwise I may change the catback down the road.
One last thing about resonance to demonstrate the power.... Every see videos of a large bridge dancing and twisting? Thats not from wind pushing the bridge, its because wind howling through the structure gave off sound that matched the resonant frequency of the bridge structure (poor engineering), which can start a vibration through the structure that builds and builds until the thing can tear itself apart.....
As far as turbos being the only source....no, no and no.
As the thread has shown its hard to describe, but "drone" is a resonance inside the cab, not sound (loud or otherwise) coming from outside. Every structure, including our truck bodies, has a "resonant frequency" where the structure will pick up and amplify a sound frequency. A lot of aftermarket exhausts hit the resonant frequency of the body when the engine is around 1800-2400 rpm, and depending on the design and volume of the system the drone can range from noticable to extremely bothersome. I've been in Mustangs that could give you a headache cruising at those rpms the resonance was so bad. Anyway, how do you avoid it? A quality exhaust company will work to reduce or eliminate sound in the frequency range that resonates in the vehicle, others just slap the same muffler style in every kit. Feedback from other users is the best way to determine which company did the job well, but as mentioned above make sure you are comparing similar vehicles. I'm a little stuck myself as I have longtubes and high flow cats and not many people have that setup so feedback is limited. I have a single 3" Flowmaster catback that was on the truck when I bought it, had zero drone when the headers and cats were stock but has quite a bit now. Currently I have some weights strapped to the long pipe in front of the muffler in an experiment to change the frequency of the vibration, it made a noticable difference in the drone level but I think a lot of it is also coming right from the muffler body. I have one more experiment to try and alter the frequency, otherwise I may change the catback down the road.
One last thing about resonance to demonstrate the power.... Every see videos of a large bridge dancing and twisting? Thats not from wind pushing the bridge, its because wind howling through the structure gave off sound that matched the resonant frequency of the bridge structure (poor engineering), which can start a vibration through the structure that builds and builds until the thing can tear itself apart.....
Senior Member
Joined: Jan 2007
Posts: 1,184
Likes: 0
From: Austin
Originally Posted by 01Roush
When people say "I've got xxxxxx system and no drone" you really need to add if you've got anything else done, and what year of truck. The '03 and down trucks are very different from the new style as far as body structure, frame, insulating material, etc.... and will NOT have the same results from each brand. Any other changes like headers or high flow cats will also make a huge difference.
As far as turbos being the only source....no, no and no.
As the thread has shown its hard to describe, but "drone" is a resonance inside the cab, not sound (loud or otherwise) coming from outside. Every structure, including our truck bodies, has a "resonant frequency" where the structure will pick up and amplify a sound frequency. A lot of aftermarket exhausts hit the resonant frequency of the body when the engine is around 1800-2400 rpm, and depending on the design and volume of the system the drone can range from noticable to extremely bothersome. I've been in Mustangs that could give you a headache cruising at those rpms the resonance was so bad. Anyway, how do you avoid it? A quality exhaust company will work to reduce or eliminate sound in the frequency range that resonates in the vehicle, others just slap the same muffler style in every kit. Feedback from other users is the best way to determine which company did the job well, but as mentioned above make sure you are comparing similar vehicles. I'm a little stuck myself as I have longtubes and high flow cats and not many people have that setup so feedback is limited. I have a single 3" Flowmaster catback that was on the truck when I bought it, had zero drone when the headers and cats were stock but has quite a bit now. Currently I have some weights strapped to the long pipe in front of the muffler in an experiment to change the frequency of the vibration, it made a noticable difference in the drone level but I think a lot of it is also coming right from the muffler body. I have one more experiment to try and alter the frequency, otherwise I may change the catback down the road.
One last thing about resonance to demonstrate the power.... Every see videos of a large bridge dancing and twisting? Thats not from wind pushing the bridge, its because wind howling through the structure gave off sound that matched the resonant frequency of the bridge structure (poor engineering), which can start a vibration through the structure that builds and builds until the thing can tear itself apart.....
As far as turbos being the only source....no, no and no.
As the thread has shown its hard to describe, but "drone" is a resonance inside the cab, not sound (loud or otherwise) coming from outside. Every structure, including our truck bodies, has a "resonant frequency" where the structure will pick up and amplify a sound frequency. A lot of aftermarket exhausts hit the resonant frequency of the body when the engine is around 1800-2400 rpm, and depending on the design and volume of the system the drone can range from noticable to extremely bothersome. I've been in Mustangs that could give you a headache cruising at those rpms the resonance was so bad. Anyway, how do you avoid it? A quality exhaust company will work to reduce or eliminate sound in the frequency range that resonates in the vehicle, others just slap the same muffler style in every kit. Feedback from other users is the best way to determine which company did the job well, but as mentioned above make sure you are comparing similar vehicles. I'm a little stuck myself as I have longtubes and high flow cats and not many people have that setup so feedback is limited. I have a single 3" Flowmaster catback that was on the truck when I bought it, had zero drone when the headers and cats were stock but has quite a bit now. Currently I have some weights strapped to the long pipe in front of the muffler in an experiment to change the frequency of the vibration, it made a noticable difference in the drone level but I think a lot of it is also coming right from the muffler body. I have one more experiment to try and alter the frequency, otherwise I may change the catback down the road.
One last thing about resonance to demonstrate the power.... Every see videos of a large bridge dancing and twisting? Thats not from wind pushing the bridge, its because wind howling through the structure gave off sound that matched the resonant frequency of the bridge structure (poor engineering), which can start a vibration through the structure that builds and builds until the thing can tear itself apart.....
I think since you've got headers and high flow cats you probably need to X pipe to dual exhausts.
I'd shoot Built54 an email, I bet he could help you out there.. He seems to have tried/done just about every mod imaginable.. lol
