I can hardly think with all this DRONE...

That setup always reminded me of Micah's car.

Yes its practically the same minus one muffler. At 3" diameter, the pipes are too large for any straight flow mufflers to do the job. Borlas XS were deemed the quietest and tested and failed, therefore going to move to the chambered turbo style unit.

My thoughts after 3 weeks of muffler shopping, the problem I encountered with selection is the 3" inlet/out, plus the limited space of 14" case size due to the mid section ending near the spare tire area. I don't want to reconstruct the mid section and that's partially my limitation.

From all this hoopla, on an extreme set up like this one, the straight flows won’t cut it. if 2.5" the options for 2.5" mufflers expand drastically, and the Borla XS have a chance to muffle better, but this is with a decent sized muffler/resonator at the center section, I don't think it matters, Magnaflow or Borla or that top secret chambered SCU thing, Jacob glass packs. But, if using an X pipe or short length glass pack, you start to get risky results for drone. Note that the longer the Borla XS case is at the rear (larger than 14) the better chance for quietness, Neibert will attest to it, and I will also even attest with the smaller 14" Borla XS and a worn out Magnaflow center. While not a set up to sneak into your house late night, they are drone free and sound beastly WOT.

Before I talk about the Stainless Works in chambered street trim, let’s talk about the Dynomax Super Turbos. When ordering the 2.5” 14” case muffler from them, you will be slightly disappointed to know that the inner pipes are believed to be only 2 1/4" on a 2.5 IN/OUT" muffler, this one is also problematic in the way it flows, on any configuration other than offset/offset opposite. A true S shape will provide the best results. The only stainless option in this trim muffler is reserved for the offset/offset opposite, so you would be in luck, but its only 409 stainless so don’t get too excited. Still need to face the fact that the inner tubes are 2.25”.


But wait! Not all hope is lost for the mighty Super Turbo from Dynomax. Hear me out, if you are willing to lower your standards and get an aluminized case with a stainless core, you are in luck, because they make a 3” IN/OUT configuration in any offset of your choosing. This 3” muffler is key because the inner pipes are in fact 3” throughout. And get this, this is the important part, the case height grows to 5.5” from the 4.5” and allows cross sectional area to be large enough for flow over the pipes when they are in a centre configured case, But length is 16” so 2” longer. This is by far the best flowing turbo chamber configuration regardless of it being offset/offset opposite or centre.

In other words, the center/offset 2 1/2" are pretty restrictive on the small case 14" units, mainly because of the obvious neck-down in pipe size (bad) and the case width being too shallow to allow the over/under flow around the center tube. Larger 3"- 16" body of the same design has a taller and wider case and actually has MORE cross sectional/flow area around the top and bottom, if you get a offset offset opposite you are even more in luck! Bigger volume, no neck down and longer muffler for noise reduction. Part #17673 #17793 for center in applications & the Offset/Offset opposite is # 17792. My suggestion is, even if running 2.5” pipes get the 3” mufflers for best performance, run adapters.

Ok that’s great news, but darn it if I am going to put on aluminized stuff on the 304SS kit, also the 16” case would require me to touch the mid Y pipes and I am not trying to reinvent the system I already have. Therefore the search leads be back to the Stainless Works muffler that Chris and I mentioned earlier. These have a 5” height so it will provide good cross sectional area over the center in pipe, not as good as dynomax 5.5” height but who is counting :(. They also don’t have that little curve diverter on it, :(, but who is can see inside anyways? Also Chris found out they are step down on the inner pipe :( . but hoping they changed their ways and made improvements and it’s a real 3” inside, a girl can dream right? :) But they were on sale for $150 vs the $109-130 for the aluminized dynomax sweetness, most of all they are 304 SS ta-da!, and that my friends is what you will see when you see me at the car shows, or looking at the back of my car after you got waxed.

Ok bible study over.

Honourable mentions,

Flowmaster 50 series in 409 stainless steel. Might give better sound (muscle car) with limited drone, but it’s a large case, and can compromise flow and HP with all the baffles and diverters.
Also to make Jacob happy, the mustang GT take offs from S197. Cheap, 409SS and 2.5” inlet, I cannot attest to flow.

I'm sure this post will be outdated if they come out with something worth trying.
BTW I still loved the sounds of the Flowmaster Force II kit when my car had stock manifolds, no cam and gutted cats, that is till a baffle or two rusted and rattled. But those were 2.25" pipes if I recall, different animal when its you got headers and larger pipes.
 
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Yes its practically the same minus one muffler. At 3" diameter, the pipes are too large for any straight flow mufflers to do the job. Borlas XS were deemed the quietest and tested and failed, therefore going to move to the chambered turbo style unit.

My thoughts after 3 weeks of muffler shopping, the problem I encountered with selection is the 3" inlet/out, plus the limited space of 14" case size due to the mid section ending near the spare tire area. I don't want to reconstruct the mid section and that's partially my limitation.

From all this hoopla, on an extreme set up like this one, the straight flows won’t cut it. if 2.5" the options for 2.5" mufflers expand drastically, and the Borla XS have a chance to muffle better, but this is with a decent sized muffler/resonator at the center section, I don't think it matters, Magnaflow or Borla or that top secret chambered SCU thing, Jacob glass packs. But, if using an X pipe or short length glass pack, you start to get risky results for drone. Note that the longer the Borla XS case is at the rear (larger than 14) the better chance for quietness, Neibert will attest to it, and I will also even attest with the smaller 14" Borla XS and a worn out Magnaflow center. While not a set up to sneak into your house late night, they are drone free and sound beastly WOT.

Before I talk about the Stainless Works in chambered street trim, let’s talk about the Dynomax Super Turbos. When ordering the 2.5” 14” case muffler from them, you will be slightly disappointed to know that the inner pipes are believed to be only 2 1/4" on a 2.5 IN/OUT" muffler, this one is also problematic in the way it flows, on any configuration other than offset/offset opposite. A true S shape will provide the best results. The only stainless option in this trim muffler is reserved for the offset/offset opposite, so you would be in luck, but its only 409 stainless so don’t get too excited. Still need to face the fact that the inner tubes are 2.25”.


But wait! Not all hope is lost for the mighty Super Turbo from Dynomax. Hear me out, if you are willing to lower your standards and get an aluminized case with a stainless core, you are in luck, because they make a 3” IN/OUT configuration in any offset of your choosing. This 3” muffler is key because the inner pipes are in fact 3” throughout. And get this, this is the important part, the case height grows to 5.5” from the 4.5” and allows cross sectional area to be large enough for flow over the pipes when they are in a centre configured case, But length is 16” so 2” longer. This is by far the best flowing turbo chamber configuration regardless of it being offset/offset opposite or centre.

In other words, the center/offset 2 1/2" are pretty restrictive on the small case 14" units, mainly because of the obvious neck-down in pipe size (bad) and the case width being too shallow to allow the over/under flow around the center tube. Larger 3"- 16" body of the same design has a taller and wider case and actually has MORE cross sectional/flow area around the top and bottom, if you get a offset offset opposite you are even more in luck! Bigger volume, no neck down and longer muffler for noise reduction. Part #17673 #17793 for center in applications & the Offset/Offset opposite is # 17792. My suggestion is, even if running 2.5” pipes get the 3” mufflers for best performance, run adapters.

Ok that’s great news, but darn it if I am going to put on aluminized stuff on the 304SS kit, also the 16” case would require me to touch the mid Y pipes and I am not trying to reinvent the system I already have. Therefore the search leads be back to the Stainless Works muffler that Chris and I mentioned earlier. These have a 5” height so it will provide good cross sectional area over the center in pipe, not as good as dynomax 5.5” height but who is counting :(. They also don’t have that little curve diverter on it, :(, but who is can see inside anyways? Also Chris found out they are step down on the inner pipe :( . but hoping they changed their ways and made improvements and it’s a real 3” inside, a girl can dream right? :) But they were on sale for $150 vs the $109-130 for the aluminized dynomax sweetness, most of all they are 304 SS ta-da!, and that my friends is what you will see when you see me at the car shows, or looking at the back of my car after you got waxed.

Ok bible study over.

Honourable mentions,

Flowmaster 50 series in 409 stainless steel. Might give better sound (muscle car) with limited drone, but it’s a large case, and can compromise flow and HP with all the baffles and diverters.
Also to make Jacob happy, the mustang GT take offs from S197. Cheap, 409SS and 2.5” inlet, I cannot attest to flow.

I'm sure this post will be outdated if they come out with something worth trying.
BTW I still loved the sounds of the Flowmaster Force II kit when my car had stock manifolds, no cam and gutted cats, that is till a baffle or two rusted and rattled. But those were 2.25" pipes if I recall, different animal when its you got headers and larger pipes.


Seriously try the gt takeoffs you wont be disappointed
 
I have room limitations. Unless I start cutting pasting.

We want mufflers that will flow what the engine needs, no more. Since once at the point of no restriction any additional cfm doesn’t increase HP but will affect the mufflers ability to work as a muffler.

Our top dog motors are making 500whp, that’s what? 500*1.25 for 20% loss? That’s 625 crank HP
From an article
600 hp on open exhaust will require 600 x 2.2 = 1,320 cfm. 2.2 being a straight pipe variable. Then Two 660-cfm mufflers will get the job done and contain the backpressureinduced power loss to 5 hp or less.

Most SC don’t make 500whp but it’s reasonable to say gives you room for growth you want a 700CFM anything more is pointless and anything less you might start to lose HP if you are a top dog engine.

Dynomax Super Turbos are advertised to flow 700 :/

I got to see what the SW chambered does. They don’t advertise it. But they confirmed the 3” in and out does go down to 2.5” internally and the louvres makes smaller. But if they flow 700 then why not.

Pypes Street Flo and Magnaflow XL are 3 chamber mufflers where the inlet pipes end in the center chamber. But no sound deadening materials. So they might sound like a Flowmaster. IDK getting decision paralysis with this.
 
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Im a few dates late on this comment... dont get the Cherry Bomb Vortex mufflers. I had a dual 2.5" to a magnaflow res, to single 3", split into dual 3" and cherry bomb vortex mufflers out back. The drone was terrible.

I used the pypes pro race muffler on my turbo v8 project and thought it sounded way better. it was a 3" in and out. of course the v8 is typically going to sound better anyways.
 
Im a few dates late on this comment... dont get the Cherry Bomb Vortex mufflers. I had a dual 2.5" to a magnaflow res, to single 3", split into dual 3" and cherry bomb vortex mufflers out back. The drone was terrible.

I used the pypes pro race muffler on my turbo v8 project and thought it sounded way better. it was a 3" in and out. of course the v8 is typically going to sound better anyways.

Thanks for the feedback. The Vortex does flow well, but glad you intercepted with your experience .

Still on the fence waiting for the Borla credit before the next purchase. I can’t get myself to go chambered unless it’s a turbo design. And the space is limiting me for options.
 
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I have room limitations. Unless I start cutting pasting.

We want mufflers that will flow what the engine needs, no more. Since once at the point of no restriction any additional cfm doesn’t increase HP but will affect the mufflers ability to work as a muffler.

Our top dog motors are making 500whp, that’s what? 500*1.25 for 20% loss? That’s 625 crank HP
From an article
600 hp on open exhaust will require 600 x 2.2 = 1,320 cfm. 2.2 being a straight pipe variable. Then Two 660-cfm mufflers will get the job done and contain the backpressureinduced power loss to 5 hp or less.

Most SC don’t make 500whp but it’s reasonable to say gives you room for growth you want a 700CFM anything more is pointless and anything less you might start to lose HP if you are a top dog engine.

Dynomax Super Turbos are advertised to flow 700 :/

I got to see what the SW chambered does. They don’t advertise it. But they confirmed the 3” in and out does go down to 2.5” internally and the louvres makes smaller. But if they flow 700 then why not.

Pypes Street Flo and Magnaflow XL are 3 chamber mufflers where the inlet pipes end in the center chamber. But no sound deadening materials. So they might sound like a Flowmaster. IDK getting decision paralysis with this.

Hi Ricardo,

Probably want to add another 100 HP to that 625 HP for driving the supercharger. BTW, sounds like your mission to make me feel silly is going about how I expected. Several years ago me and DD had a lengthy discussion about what could or should be done to my super cool exhaust system to make it quieter at part throttle and get rid of the drone. Conclusion...Start over and build a new exhaust system.

David
 
Hi Ricardo,

Probably want to add another 100 HP to that 625 HP for driving the supercharger. BTW, sounds like your mission to make me feel silly is going about how I expected. Several years ago me and DD had a lengthy discussion about what could or should be done to my super cool exhaust system to make it quieter at part throttle and get rid of the drone. Conclusion...Start over and build a new exhaust system.

David

Not giving up just yet, there is still Helmholtz tube idea and keep these magnaflows. For now I’m giving it a break.
 
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Why did you buy this exhaust lol

I got it for a song. :p it looks and performs as expected, Neibert and Dalke didn’t hide that it was loud. And I like the WOT sounds, Dalke suggested a new resonator when I picked up. I was well aware of the consequences, but I didn’t think I was going to be so limited on choices of mufflers, and that’s really all this thing needs to make it not drone, that or change the frequency. The VT mufflers would have done wonders but I missed that boat or maybe it was a good thing IDK. I feel hot rodding is losing its luster and market cause there were a few more choices 10 years ago.
 
From another website/forum:


“The concept behind drone is pretty simple; nearly everything has a resonant frequency...exhaust systems, electronic RLC circuits, even gravitation has resonance. At peak resonance, the amplitude of the wave at the resonant frequency shoots up to many times higher than normal amplitude. With sound resonance, it pops up when a certain frequency emitted from the engine resonates with the exhaust system and muffler to create that nasty in-cab drone. Unfortunately this resonance often has its peak right in the area where you want to cruise, between 55-75mph.

The solution is a 1/4 wave resonator tube. Simply put, it is a small piece of exhaust pipe with a flat capped end welded nearly perpendicular to the exhaust flow post-muffler that serves to take some of the resonant amplitude and shoot it back into the exhaust pipe out of phase with the resonant frequency to bring down the amplitude. If you've ever taken a physics class, this is in the 'standing wave dynamics' chapter. Mufflers are designed to bring down the amplitude or volume of the exhaust note at all RPMs, but they typically can't do anything about resonance.

Things you need to know to build the resonator: (Super Coupe)

-RPM that drone occurs at
-Number of cylinders (6)

You will also need to know the speed of sound. It varies with temperature, but is generally accepted to be 343m/s.

Say your Super Coupe resonates at 1,800rpms, right at cruising speed. You'll need to find the frequency of the drone. Units here are pulses per second, or Hertz.

f = RPM * pulses/rev * (1/60)

f = 1800 rev/min for an SC * 3 pulses/rev for an SC * (1/60) RPMins to RPSeconds

f = 90 pulses/second = 90Hz

At 1,800rpms, your SCV6 fires 3 times per revolution. RPM is in minutes, so divide by 60 to reduce to seconds. Now you need to find the length of the wave at the frequency you just calculated. Wavelength is denoted by lambda (λ), units are meters.

λ = v/f = speed of sound / frequency

λ = (343m/s)/(90Hz)

λ = 3.8 meters NICE!

This gives you the length of a full sound wave. The idea here is to reintroduce a sound wave into the exhaust that is 180° out of phase with your drone frequency. To do this, you build your resonator tube at exactly one-fourth the length of the resonant wave. By the time the sound wave enters the resonator tube, bounces off the end and re-enters the exhaust stream, the amplitude is exactly opposite of the drone frequency and will lower or eliminate the volume of the drone.

Dividing the wavelength by 4 gives you 0.95m, or about 3.2 feet.

The diameter of the tube you'd need is debatable, I assume a larger resonator tube would allow more sound to bounce back and cancel more of the drone noise. However, space is somewhat limited when you are sending an exhaust pipe off of your existing pipe at some odd angle. You can bend the resonator tube to some extent, but it needs to be mandrel bent, not more than one bend or more than ~30°. If the bend is too sharp, the sound will bounce back too early and the resonator will work poorly or won't work at all.

The reason for this is simply the fact that sound waves do not necessarily 'flow' with whatever medium they are travelling in. Sound is a pressure wave, and any obstacle (bends) will return the wave prematurely. To minimize 'obstacles' in the resonator tube, the straighter it is, the better it will work. The intent is not to randomly scatter the sound wave as a radius will tend to do, but to send it back to the exhaust precisely when it is needed.

As you can see I replaced its original variables with SC variables, where I am still confused is the above is for a single exhaust, when using on a dual exhaust do we then split the 3.2 feet into two? 1.6 feet?
 
From another website/forum:


“The concept behind drone is pretty simple; nearly everything has a resonant frequency...exhaust systems, electronic RLC circuits, even gravitation has resonance. At peak resonance, the amplitude of the wave at the resonant frequency shoots up to many times higher than normal amplitude. With sound resonance, it pops up when a certain frequency emitted from the engine resonates with the exhaust system and muffler to create that nasty in-cab drone. Unfortunately this resonance often has its peak right in the area where you want to cruise, between 55-75mph.

The solution is a 1/4 wave resonator tube. Simply put, it is a small piece of exhaust pipe with a flat capped end welded nearly perpendicular to the exhaust flow post-muffler that serves to take some of the resonant amplitude and shoot it back into the exhaust pipe out of phase with the resonant frequency to bring down the amplitude. If you've ever taken a physics class, this is in the 'standing wave dynamics' chapter. Mufflers are designed to bring down the amplitude or volume of the exhaust note at all RPMs, but they typically can't do anything about resonance.

Things you need to know to build the resonator: (Super Coupe)

-RPM that drone occurs at
-Number of cylinders (6)

You will also need to know the speed of sound. It varies with temperature, but is generally accepted to be 343m/s.

Say your Super Coupe resonates at 1,800rpms, right at cruising speed. You'll need to find the frequency of the drone. Units here are pulses per second, or Hertz.

f = RPM * pulses/rev * (1/60)

f = 1800 rev/min for an SC * 3 pulses/rev for an SC * (1/60) RPMins to RPSeconds

f = 90 pulses/second = 90Hz

At 1,800rpms, your SCV6 fires 3 times per revolution. RPM is in minutes, so divide by 60 to reduce to seconds. Now you need to find the length of the wave at the frequency you just calculated. Wavelength is denoted by lambda (λ), units are meters.

λ = v/f = speed of sound / frequency

λ = (343m/s)/(90Hz)

λ = 3.8 meters NICE!

This gives you the length of a full sound wave. The idea here is to reintroduce a sound wave into the exhaust that is 180° out of phase with your drone frequency. To do this, you build your resonator tube at exactly one-fourth the length of the resonant wave. By the time the sound wave enters the resonator tube, bounces off the end and re-enters the exhaust stream, the amplitude is exactly opposite of the drone frequency and will lower or eliminate the volume of the drone.

Dividing the wavelength by 4 gives you 0.95m, or about 3.2 feet.

The diameter of the tube you'd need is debatable, I assume a larger resonator tube would allow more sound to bounce back and cancel more of the drone noise. However, space is somewhat limited when you are sending an exhaust pipe off of your existing pipe at some odd angle. You can bend the resonator tube to some extent, but it needs to be mandrel bent, not more than one bend or more than ~30°. If the bend is too sharp, the sound will bounce back too early and the resonator will work poorly or won't work at all.

The reason for this is simply the fact that sound waves do not necessarily 'flow' with whatever medium they are travelling in. Sound is a pressure wave, and any obstacle (bends) will return the wave prematurely. To minimize 'obstacles' in the resonator tube, the straighter it is, the better it will work. The intent is not to randomly scatter the sound wave as a radius will tend to do, but to send it back to the exhaust precisely when it is needed.

As you can see I replaced its original variables with SC variables, where I am still confused is the above is for a single exhaust, when using on a dual exhaust do we then split the 3.2 feet into two? 1.6 feet?


Ive thought about this a lot with those vortex mufflers. I never got around to doing it, but I concluded that the best solution was to make the tube length adjustable. Guess and test, then figure out the length that works and then weld it up solid.
 
I think I am back on the mission. Carefully reading through part numbers and descriptions. I was able figure out a Stainless Works offering that will be turbo chambered like the Dynomax, and be 3” on the inside triple core pipes. I had to move away from center in configuration to both offset and opposite, in that they have the space to install the 3” through out. I feel the center configuration is why the one Chris and I needed is limited to 2.5” so air can cross over and under the center pipe. But the case being 5” it becomes a problem.

Anyways, full MSRP on this one and I’ll need to possibly modify the axle pipes to give me the angle to do the tail pipes.

Stainless Works.
TM5C3O3OPS
3" ID OFFSET INLET/ 3" OD OFFSET OUTLET, 3.000" DIA CORE, 5 x 9 x 14" SHELL 304 SS CHAMBERED TURBO MUFF
 
Situation is hilarious, I got the call from Jegs only to be disappointed to know stainless works discontinued the above mentioned part number. I called Summit and they were holding on to the last set in their inventory. Challenge remains we will see how it goes when the unicorn arrives.
 
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