True V8 sound, 5.4, Flowmaster and my FX4
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Senior Member
Joined: Dec 2005
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From: NJ
True V8 sound, 5.4, Flowmaster and my FX4
I kinda got into a discussion on this in the oem exhaust section and thought I'd bring the discussion here.
I recently installed the Flowmaster SI/DO system with the super 40 series muffler. The sound for the most part is great. Early on a cold morning, turning the key it sounds great, at idle and when accelerating whether half or WoT sounds like "it should".
However the problem begins when driving down your average street or highway (30mph and 65-75mph). The interior resonance is the only thing you can hear and it does not sound like a high performance V8 but to me drones on like an oversized fart can on a civic.
Flowmaster is not to blame as right on thier website they talk about the "resonance" at the offending rpm's.... And I will be replacing the 40 with a delta 50 and hope I don't have the opposite problem (too quiet)
To an amature like myself it seems to me that the lower compression of the 5.4 (relative to the 3" pipe), the large cat, and the 3" to a dual out 2.50" transition creates a lower exhaust pressure and hence the "drone" as the air freely flows slower and "resonates" the muffler. Flowmaster from thier website seems to indicate that the 50 series with its "internal chamber" or whatever they call it is designed to minimize this drone but at the same time sacrifices the volume of the actual exhaust note. This I am thinking creates back pressure and causes air to move "faster" through the more restrictive system thus reducing "drone" and increasing the high performance (though not as loud) sound...
I base this all on my experience with my 67 mustang with a 289 hipo, 10:1 compression with headers, h-pipe dual 40's "true dual" and the 2002 Vette I just sold that had GHL headers and mufflers also "true dual". Neither of which drone like the 40 on my f150 though both are/were significantly louder than the f150 at WOT.......
Which begs the question of what does a true dual and headers with 40's sound like on the f150 with smaller pipeq (2.50" or less). Is drone decreased due to the "total free flow" of the exaust system combined with the smaller pipes that still match the output of the engine? (of course that would mean free flow cats or some other method)......
What say you.... I am mostly thinking out loud here....
I recently installed the Flowmaster SI/DO system with the super 40 series muffler. The sound for the most part is great. Early on a cold morning, turning the key it sounds great, at idle and when accelerating whether half or WoT sounds like "it should".
However the problem begins when driving down your average street or highway (30mph and 65-75mph). The interior resonance is the only thing you can hear and it does not sound like a high performance V8 but to me drones on like an oversized fart can on a civic.
Flowmaster is not to blame as right on thier website they talk about the "resonance" at the offending rpm's.... And I will be replacing the 40 with a delta 50 and hope I don't have the opposite problem (too quiet)
To an amature like myself it seems to me that the lower compression of the 5.4 (relative to the 3" pipe), the large cat, and the 3" to a dual out 2.50" transition creates a lower exhaust pressure and hence the "drone" as the air freely flows slower and "resonates" the muffler. Flowmaster from thier website seems to indicate that the 50 series with its "internal chamber" or whatever they call it is designed to minimize this drone but at the same time sacrifices the volume of the actual exhaust note. This I am thinking creates back pressure and causes air to move "faster" through the more restrictive system thus reducing "drone" and increasing the high performance (though not as loud) sound...
I base this all on my experience with my 67 mustang with a 289 hipo, 10:1 compression with headers, h-pipe dual 40's "true dual" and the 2002 Vette I just sold that had GHL headers and mufflers also "true dual". Neither of which drone like the 40 on my f150 though both are/were significantly louder than the f150 at WOT.......
Which begs the question of what does a true dual and headers with 40's sound like on the f150 with smaller pipeq (2.50" or less). Is drone decreased due to the "total free flow" of the exaust system combined with the smaller pipes that still match the output of the engine? (of course that would mean free flow cats or some other method)......
What say you.... I am mostly thinking out loud here....
Senior Member
Joined: Aug 2004
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From: North Huntingdon,Pa.
sound
Originally Posted by WaWaTuSi
I kinda got into a discussion on this in the oem exhaust section and thought I'd bring the discussion here.
I recently installed the Flowmaster SI/DO system with the super 40 series muffler. The sound for the most part is great. Early on a cold morning, turning the key it sounds great, at idle and when accelerating whether half or WoT sounds like "it should".
However the problem begins when driving down your average street or highway (30mph and 65-75mph). The interior resonance is the only thing you can hear and it does not sound like a high performance V8 but to me drones on like an oversized fart can on a civic.
Flowmaster is not to blame as right on thier website they talk about the "resonance" at the offending rpm's.... And I will be replacing the 40 with a delta 50 and hope I don't have the opposite problem (too quiet)
To an amature like myself it seems to me that the lower compression of the 5.4 (relative to the 3" pipe), the large cat, and the 3" to a dual out 2.50" transition creates a lower exhaust pressure and hence the "drone" as the air freely flows slower and "resonates" the muffler. Flowmaster from thier website seems to indicate that the 50 series with its "internal chamber" or whatever they call it is designed to minimize this drone but at the same time sacrifices the volume of the actual exhaust note. This I am thinking creates back pressure and causes air to move "faster" through the more restrictive system thus reducing "drone" and increasing the high performance (though not as loud) sound...
I base this all on my experience with my 67 mustang with a 289 hipo, 10:1 compression with headers, h-pipe dual 40's "true dual" and the 2002 Vette I just sold that had GHL headers and mufflers also "true dual". Neither of which drone like the 40 on my f150 though both are/were significantly louder than the f150 at WOT.......
Which begs the question of what does a true dual and headers with 40's sound like on the f150 with smaller pipeq (2.50" or less). Is drone decreased due to the "total free flow" of the exaust system combined with the smaller pipes that still match the output of the engine? (of course that would mean free flow cats or some other method)......
What say you.... I am mostly thinking out loud here....
I recently installed the Flowmaster SI/DO system with the super 40 series muffler. The sound for the most part is great. Early on a cold morning, turning the key it sounds great, at idle and when accelerating whether half or WoT sounds like "it should".
However the problem begins when driving down your average street or highway (30mph and 65-75mph). The interior resonance is the only thing you can hear and it does not sound like a high performance V8 but to me drones on like an oversized fart can on a civic.
Flowmaster is not to blame as right on thier website they talk about the "resonance" at the offending rpm's.... And I will be replacing the 40 with a delta 50 and hope I don't have the opposite problem (too quiet)
To an amature like myself it seems to me that the lower compression of the 5.4 (relative to the 3" pipe), the large cat, and the 3" to a dual out 2.50" transition creates a lower exhaust pressure and hence the "drone" as the air freely flows slower and "resonates" the muffler. Flowmaster from thier website seems to indicate that the 50 series with its "internal chamber" or whatever they call it is designed to minimize this drone but at the same time sacrifices the volume of the actual exhaust note. This I am thinking creates back pressure and causes air to move "faster" through the more restrictive system thus reducing "drone" and increasing the high performance (though not as loud) sound...
I base this all on my experience with my 67 mustang with a 289 hipo, 10:1 compression with headers, h-pipe dual 40's "true dual" and the 2002 Vette I just sold that had GHL headers and mufflers also "true dual". Neither of which drone like the 40 on my f150 though both are/were significantly louder than the f150 at WOT.......
Which begs the question of what does a true dual and headers with 40's sound like on the f150 with smaller pipeq (2.50" or less). Is drone decreased due to the "total free flow" of the exaust system combined with the smaller pipes that still match the output of the engine? (of course that would mean free flow cats or some other method)......
What say you.... I am mostly thinking out loud here....