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Yellow Mach 1 is back again!
Very good points Eric!  I also believe the muffler style has a lot to do with it. The 40 series are chambered mufflers and the flow fx are a straight through design. The sound waves bouncing around in the chambers maybe giving it that droning sound everyone complains of. The FX are a straight shot with packing around it. 

[Image: C478225-B-FE46-4856-BE09-8-F2-A6554462-F.jpg]

[Image: CF67444-D-7759-4689-A6-F3-FA436779-AE7-C.gif]

Kevin

1971 Mach 1
408C Stroker
C4 w/3,000 stall
8.8" Rear w/3.73's
Disc brakes all way around.

[Image: 28ivsix.png]




                                                                                             
  Reply
Kevin, thanks for your reply and input.
My car currently has an H pipe and 2 1/4" pipes with factory manifolds (M code car), but as I really need to replace the entire system, maybe a X pipe is the way to go. I'm not to familiar the physics of how resonance actually works, but I have worked on air induction resonators for cars. I mean I have a basic idea and from what little I know the H pipe connection is there to balance the flow between the two pies. What turbulence there is and how it reacts, I'm not sure.
Regardless in my car, even with all the sound deadening stuff I put in, the "drone" is ear splitting until I get past that rpm range, then it's just a good power sound.
That's why it's got to go and why this input is so helpful.
Thanks
Geoff.

I learn something new every day!
  Reply
(03-20-2019, 08:44 AM)Mister 4x4 Wrote: Since I'm an Edelbrock guy, I'd say blame the Holley.   Haha


Sounds awesome!  Well done!  thumb

I'd also heard of the droning issue with the Flowmasters, but that's an interesting theory regarding the H-pipe vs. X-pipe.  I wouldn't have thought that it would make such a difference, but you can definitely tell the difference in sound characteristics between cars that have H-pipes and X-pipes.  H-pipes seem to have just a little bit more of a bass note sound than the X-pipes at idle.  I'm thinking it might have something to do with the exhaust flow slamming into and having to turn the corner when it hits the H-pipe junction, instead of just flowing together and pushing on down the pipes with the X-pipe configuration.  Having to suddenly change direction or having a smoother path would have an effect on the sound waves and vibrations of the exhaust system as well.  I could be all wrong on this, but I believe the H-pipe might actually cause just a tiny bit of turbulence in the exhaust flow - or maybe a little bit moreso than the X-pipe at the very least, with sound, gases, etc., all wrapped up in the mix and affected similarly - could be the difference.  I've noticed that most things involving repetitive motion tend to have a 'bad' spot somewhere that the balance is just a teeny bit off, which creates vibrations, noise, loss of efficiency, etc.,  Sound works similarly - when vibrations are tuned properly, the overall sound tends to smooth out and even decrease in volume somewhat, but if the soundwaves aren't in complete synch, the opposing secondary waves add to the volume and choppiness of the sound (I experience that effect every Tuesday night at Community Band rehearsal when the clarinets and saxophones don't feel the need to tune themselves before we start playing, which is quite annoying rofl ).

As for the drone, some mufflers are better than others at eliminating or minimizing the drone, which I would suspect has everything to do with the path the exhaust must take through the mufflers - they're basically just rat mazes inside, after all, with some having more insulation packed in than others.  Obviously, the less restrictive the muffler is, the louder it tends to be, since there is less insulating material and bends in the 'maze' for the exhaust flow to contend with.  Since the drone most likely has more to do with harmonics than simple noise, I don't think the mufflers really ever elminate it totally, but rather just dampen it to the point it's less noticeable.

OR - I could be totally off-base here and just talking out me arse.   whistling
 Good input Eric, thanks.
Your last sentence, do you have any "Brit" in you? That's a so typical Brit expression and spelling!!

I learn something new every day!
  Reply
(03-20-2019, 10:04 AM)Stanglover Wrote: Kevin, thanks for your reply and input.
My car currently has an H pipe and 2 1/4" pipes with factory manifolds (M code car), but as I really need to replace the entire system, maybe a X pipe is the way to go. I'm not to familiar the physics of how resonance actually works, but I have worked on air induction resonators for cars. I mean I have a basic idea and from what little I know the H pipe connection is there to balance the flow between the two pies. What turbulence there is and how it reacts, I'm not sure.
Regardless in my car, even with all the sound deadening stuff I put in, the "drone" is ear splitting until I get past that rpm range, then it's just a good power sound.
That's why it's got to go and why this input is so helpful.
Thanks
Geoff.

Geoff, I'm glad the info helped.  I can say without a doubt there is NO resonance that is even mildly earsplitting or annoying with this particular system! Just a nice V8 rumble.

Kevin

1971 Mach 1
408C Stroker
C4 w/3,000 stall
8.8" Rear w/3.73's
Disc brakes all way around.

[Image: 28ivsix.png]




                                                                                             
  Reply
[attachment=48832 Wrote:turtle5353 pid='341891' dateline='1553094608']
(03-20-2019, 10:04 AM)Stanglover Wrote: Kevin, thanks for your reply and input.
My car currently has an H pipe and 2 1/4" pipes with factory manifolds (M code car), but as I really need to replace the entire system, maybe a X pipe is the way to go. I'm not to familiar the physics of how resonance actually works, but I have worked on air induction resonators for cars. I mean I have a basic idea and from what little I know the H pipe connection is there to balance the flow between the two pies. What turbulence there is and how it reacts, I'm not sure.
Regardless in my car, even with all the sound deadening stuff I put in, the "drone" is ear splitting until I get past that rpm range, then it's just a good power sound.
That's why it's got to go and why this input is so helpful.
Thanks
Geoff.

Geoff, I'm glad the info helped.  I can say without a doubt there is NO resonance that is even mildly earsplitting or annoying with this particular system! Just a nice V8 rumble.

 Kevin, that great news.
 For those interested and yes, probably should start this in a new post, but while we're here, I looked up the Flowmaster Fx series. I found a web site,  There is some good info there with a YouTube video. From there I found a Summit video from Flowmaster, "how to select he right flowmaster muffler for your vehicle"
Though it might be good info for all. Interestingly, the guy in the video says the Flowmaster Delta 50, although longer at 17" will give that nice note, but greatly reduced drone in the cabin, so that might be another consideration.
One thing leads to another I guess!
Geoff.
EDIT< something wrong with the link, I typed it as it showed, but not fully working. Hmmm, I'll check and get back.
Ok this should work now, copied directly.

I learn something new every day!
  Reply
(03-20-2019, 10:08 AM)Stanglover Wrote:
(03-20-2019, 08:44 AM)Mister 4x4 Wrote: Since I'm an Edelbrock guy, I'd say blame the Holley.   Haha


Sounds awesome!  Well done!  thumb

I'd also heard of the droning issue with the Flowmasters, but that's an interesting theory regarding the H-pipe vs. X-pipe.  I wouldn't have thought that it would make such a difference, but you can definitely tell the difference in sound characteristics between cars that have H-pipes and X-pipes.  H-pipes seem to have just a little bit more of a bass note sound than the X-pipes at idle.  I'm thinking it might have something to do with the exhaust flow slamming into and having to turn the corner when it hits the H-pipe junction, instead of just flowing together and pushing on down the pipes with the X-pipe configuration.  Having to suddenly change direction or having a smoother path would have an effect on the sound waves and vibrations of the exhaust system as well.  I could be all wrong on this, but I believe the H-pipe might actually cause just a tiny bit of turbulence in the exhaust flow - or maybe a little bit moreso than the X-pipe at the very least, with sound, gases, etc., all wrapped up in the mix and affected similarly - could be the difference.  I've noticed that most things involving repetitive motion tend to have a 'bad' spot somewhere that the balance is just a teeny bit off, which creates vibrations, noise, loss of efficiency, etc.,  Sound works similarly - when vibrations are tuned properly, the overall sound tends to smooth out and even decrease in volume somewhat, but if the soundwaves aren't in complete synch, the opposing secondary waves add to the volume and choppiness of the sound (I experience that effect every Tuesday night at Community Band rehearsal when the clarinets and saxophones don't feel the need to tune themselves before we start playing, which is quite annoying rofl ).

As for the drone, some mufflers are better than others at eliminating or minimizing the drone, which I would suspect has everything to do with the path the exhaust must take through the mufflers - they're basically just rat mazes inside, after all, with some having more insulation packed in than others.  Obviously, the less restrictive the muffler is, the louder it tends to be, since there is less insulating material and bends in the 'maze' for the exhaust flow to contend with.  Since the drone most likely has more to do with harmonics than simple noise, I don't think the mufflers really ever elminate it totally, but rather just dampen it to the point it's less noticeable.

OR - I could be totally off-base here and just talking out me arse.   whistling
 Good input Eric, thanks.
Your last sentence, do you have any "Brit" in you? That's a so typical Brit expression and spelling!!

No - nothing like that.  I do interface with with some Brits, Scots, and Aussies now and then on the various forums here and there, but I'm actually half-Danish (father's side) and American Mutt (Mom's) for the most part.  I've also got a lot of experiece on what passes thru online language filters and what might not. Wink

Eric

[Image: mach1sig2.gif]
  Reply
(03-20-2019, 01:13 PM)Mister 4x4 Wrote:
(03-20-2019, 10:08 AM)Stanglover Wrote:
(03-20-2019, 08:44 AM)Mister 4x4 Wrote: Since I'm an Edelbrock guy, I'd say blame the Holley.   Haha


Sounds awesome!  Well done!  thumb
 Good input Eric, thanks.
Your last sentence, do you have any "Brit" in you? That's a so typical Brit expression and spelling!!

No - nothing like that.  I do interface with some Brits, Scots, and Aussies now and then on the various forums here and there, but I'm actually half-Danish (father's side) and American Mutt (Mom's) for the most part.  I've also got a lot of experiece on what passes thru online language filters and what might not. Wink
 Ah! I see. I don't often see Americans spell "ass" as arse. But then American spelling gets me all the time, but I'm learning how to spell the lazy way!! lol. Okay, simplified.

I learn something new every day!
  Reply
Finished up tuning the car this week. Hand rubbed it out with 3m hand glaze. And the owner picked it up today! 

[Image: 2-B3-E1554-1-C82-4-B4-C-BC77-CA55-E52-D180-B.jpg]

[Image: 71-D24287-0350-4172-B07-F-92330679-F0-AA.jpg]

[Image: 0-FEB86-A0-A55-C-4291-9-D15-9-CAB59-E78959.jpg]

[Image: 9-EC68-FD7-1-E84-4449-A7-D1-F9767-B87-ECA3.jpg]

Kevin

1971 Mach 1
408C Stroker
C4 w/3,000 stall
8.8" Rear w/3.73's
Disc brakes all way around.

[Image: 28ivsix.png]




                                                                                             
  Reply
Looks really good man. Nice job!
  Reply
You do fantastic work. Hope the rust does not eat out again. He needs to keep the water hose off the car. Only wipe with wet micro fiber towels. Water just feed the rust.


When a man is in the woods and talks and no women are there is he still wrong??
Tongue
David
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