Which unmodified mufflers act as pressure wave termination box?

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ptuomov
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Re: Which unmodified mufflers act as pressure wave termination box?

Post by ptuomov » Mon Aug 13, 2018 5:07 pm

NewbVetteGuy wrote:
Mon Aug 13, 2018 4:54 pm
ptuomov wrote:
Fri Aug 10, 2018 8:40 am

Third, the pipe cross-sectional area should go down as the exhaust gas cools towards the end of the car and the mufflers should be placed as far back as they fit. This is because smaller the ratio of the exhaust pipe area to case cross-sectional area, the greater the effectiveness of the muffler.
Placement of the muffler as far back as possible if trying to use the mufflers as a pressure wave termination box doesn't make any sense to me. I thought the purpose was to tune the header + "extension" length just like open headers by having the large exhaust volume (muffler/wave term box) at the tuned length.

(Place the opening into the muffler chamber at the point that PipeMax tells you to; no?)

Adam
You’re going to need more than one set of mufflers to quiet a car down efficiently.
Paradigms often shift without the clutch -- https://www.youtube.com/watch?v=cxn-LxwsrnU

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Re: Which unmodified mufflers act as pressure wave termination box?

Post by ChargerST » Tue Aug 14, 2018 1:54 am

67RS502 wrote:
Mon Aug 13, 2018 1:29 pm
Youre looking for chambered mufflers (volume) not packing mufflers (straight thru like a pipe)
Hooker Aerochambers have volume and a deep sound, since the walls have a foam type inner insulation.
Thanks! I was looking at the Aerochambers but couldn't find a spec on the volume of the expansion chamber (which looks a little bit too small for my engine). I'd like to have a minimum volume of 2 x engine displacement or in my case 2 x cylinder bank displacement (I have a dual exhaust). So PWTB volume should be at least 500ci per side.

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Re: Which unmodified mufflers act as pressure wave termination box?

Post by Fireonthemountain » Wed Aug 15, 2018 12:11 pm

ChargerST wrote:
Tue Aug 14, 2018 1:54 am
67RS502 wrote:
Mon Aug 13, 2018 1:29 pm
Youre looking for chambered mufflers (volume) not packing mufflers (straight thru like a pipe)
Hooker Aerochambers have volume and a deep sound, since the walls have a foam type inner insulation.
Thanks! I was looking at the Aerochambers but couldn't find a spec on the volume of the expansion chamber (which looks a little bit too small for my engine). I'd like to have a minimum volume of 2 x engine displacement or in my case 2 x cylinder bank displacement (I have a dual exhaust). So PWTB volume should be at least 500ci per side.
Don't pay any attention to me, but if you had 2 aerochambers side by side per side....double the capacity...double the flow...and quieter.

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Re: Which unmodified mufflers act as pressure wave termination box?

Post by NewbVetteGuy » Thu Aug 16, 2018 4:03 pm

ptuomov wrote:
Mon Aug 13, 2018 5:07 pm
NewbVetteGuy wrote:
Mon Aug 13, 2018 4:54 pm
ptuomov wrote:
Fri Aug 10, 2018 8:40 am

Third, the pipe cross-sectional area should go down as the exhaust gas cools towards the end of the car and the mufflers should be placed as far back as they fit. This is because smaller the ratio of the exhaust pipe area to case cross-sectional area, the greater the effectiveness of the muffler.
Placement of the muffler as far back as possible if trying to use the mufflers as a pressure wave termination box doesn't make any sense to me. I thought the purpose was to tune the header + "extension" length just like open headers by having the large exhaust volume (muffler/wave term box) at the tuned length.

(Place the opening into the muffler chamber at the point that PipeMax tells you to; no?)

Adam
You’re going to need more than one set of mufflers to quiet a car down efficiently.
Thanks. Now I understand where you were going with that.

I saw the OPs question as focused on how to use a muffler as a pressure wave termination box as a question focused on how to improve performance AND not have to build a pressure wave termination box from scratch. -The sudden switch from what appeared to be a performance-oriented question to a noise reduction-focused answer definitely caught me off-guard. I didn't context switch with you there.



Adam

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Re: Which unmodified mufflers act as pressure wave termination box?

Post by ptuomov » Thu Aug 16, 2018 5:57 pm

NewbVetteGuy wrote:
Thu Aug 16, 2018 4:03 pm
ptuomov wrote:
Mon Aug 13, 2018 5:07 pm
NewbVetteGuy wrote:
Mon Aug 13, 2018 4:54 pm


Placement of the muffler as far back as possible if trying to use the mufflers as a pressure wave termination box doesn't make any sense to me. I thought the purpose was to tune the header + "extension" length just like open headers by having the large exhaust volume (muffler/wave term box) at the tuned length.

(Place the opening into the muffler chamber at the point that PipeMax tells you to; no?)

Adam
You’re going to need more than one set of mufflers to quiet a car down efficiently.
Thanks. Now I understand where you were going with that.

I saw the OPs question as focused on how to use a muffler as a pressure wave termination box as a question focused on how to improve performance AND not have to build a pressure wave termination box from scratch. -The sudden switch from what appeared to be a performance-oriented question to a noise reduction-focused answer definitely caught me off-guard. I didn't context switch with you there.

Adam
I was drifting away from the original poster’s question, so my bad.
Paradigms often shift without the clutch -- https://www.youtube.com/watch?v=cxn-LxwsrnU

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Re: Which unmodified mufflers act as pressure wave termination box?

Post by ptuomov » Thu Aug 16, 2018 6:01 pm

More drift, this is where we ended up in:
8E632A69-B384-41C0-B5AE-4DFDE53C7FFB.jpeg
You do not have the required permissions to view the files attached to this post.
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Re: Which unmodified mufflers act as pressure wave termination box?

Post by modok » Thu Aug 16, 2018 11:37 pm

IMO the idea of a "termination box" is really not that ideal.
I think....the idea is it will perform the same as if it wasn't there, so, you can develop the system with no muflers.

Does that make sense? Not really.
If it's going to have mufflers, then, develop the system with mufflers. It might even work BETTER.

It could be said that in a race car....having mufflers would slow you down from the weight, and needed space.....but that does not mean they don't have the possibility to be tuned to make just as much or more overall power.
It just means they are heavy and take up space. BUT If you HAVE to have them anyway,, then that's not a choice.
Tube it with the mufflers!!!

For instance, this termination volume....you'd think bigger is better but it may not be so. Would be very common to find past a certain point you'd lose some low end and gain nothing. Even the far end of the tailpipe can change how it idles. If you have an auto maybe it could fine something that works well right at the stall speed. The termination box is a convienent idea but it isn't necessarily the ideal.
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Re: Which unmodified mufflers act as pressure wave termination box?

Post by emsvitil » Fri Aug 17, 2018 1:21 am

A large hollowed out cat converter.

It's very close to the right location, and it looks like you're being green.

:mrgreen:
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Re: Which unmodified mufflers act as pressure wave termination box?

Post by user-23911 » Fri Aug 17, 2018 2:22 am

You can't reduce the sound level without affecting the waves.


So wave termination box?
Everything is but to a different extent.

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Re: Which unmodified mufflers act as pressure wave termination box?

Post by Fireonthemountain » Sat Aug 18, 2018 3:13 am

I am not too worried about the wave, with the first muffler or mufflers, at a certain distance or more back from the engine, and this time the first one I am putting on is before the rear axle, with aero chambers. With my limited brain, I figure the wave, if it still exist that far out will collapse there, with them absorbing heat. So cooling the gases compressing in them and flowing through quiet rapidly. But slowing by exit, as it now makes a turn up over the axle then entering a couple of large dynomax turbo mufflers. It all depends on the desired results you want and the power ya got.

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Re: Which unmodified mufflers act as pressure wave termination box?

Post by Aukai » Sat Aug 18, 2018 4:12 am

I would like to ask,and I have read this late at night, and hope I make sense. I have a 70 Chevelle with a 900+ hp 7500+RPM 572 with 2 1/4" headers, 3.5" exhaust with X pipes, and 20" Magnaflow mufflers before the rear end. How would adding 3" tail pipes over the rear end, and out of the back effect performance?
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Re: Which unmodified mufflers act as pressure wave termination box?

Post by Warp Speed » Sat Aug 18, 2018 8:38 am

Aukai wrote:
Sat Aug 18, 2018 4:12 am
I would like to ask,and I have read this late at night, and hope I make sense. I have a 70 Chevelle with a 900+ hp 7500+RPM 572 with 2 1/4" headers, 3.5" exhaust with X pipes, and 20" Magnaflow mufflers before the rear end. How would adding 3" tail pipes over the rear end, and out of the back effect performance?
I wouldn't step them down after the mufflers, but my extensive exhaust testing doesn't involve mufflers. Going smaller with the cross section the farther down stream theory goes against anything I've ever found.

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Re: Which unmodified mufflers act as pressure wave termination box?

Post by RevTheory » Sat Aug 18, 2018 9:50 am

Warp Speed wrote:
Sat Aug 18, 2018 8:38 am
I wouldn't step them down after the mufflers, but my extensive exhaust testing doesn't involve mufflers. Going smaller with the cross section the farther down stream theory goes against anything I've ever found.
I almost posted you mentioning that at the onset of this thread but I thought I'd let you tackle it :)

I remember Calvin talking about always wanting to get to a single exit pipe if the application allowed but I don't ever remember him reducing area as he got there.

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Re: Which unmodified mufflers act as pressure wave termination box?

Post by Aukai » Sat Aug 18, 2018 2:00 pm

Thank you Warp, threading a 3.5 tail pipe through shocks, ARB arms, and the gas tank will probably mandate dumping at the axle. Any truth to the theory of noise canceling angling the turn downs toward each other, sorry I'm taking this off subject.
Mike Lewis street 572
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http://www.lewisracingengines.com/

"You know you have the power, and if you use that power bad things are going to happen"

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Re: Which unmodified mufflers act as pressure wave termination box?

Post by pdq67 » Sat Aug 18, 2018 3:24 pm

ptuomov wrote:
Mon Aug 13, 2018 5:07 pm
NewbVetteGuy wrote:
Mon Aug 13, 2018 4:54 pm
ptuomov wrote:
Fri Aug 10, 2018 8:40 am

Third, the pipe cross-sectional area should go down as the exhaust gas cools towards the end of the car and the mufflers should be placed as far back as they fit. This is because smaller the ratio of the exhaust pipe area to case cross-sectional area, the greater the effectiveness of the muffler.
Placement of the muffler as far back as possible if trying to use the mufflers as a pressure wave termination box doesn't make any sense to me. I thought the purpose was to tune the header + "extension" length just like open headers by having the large exhaust volume (muffler/wave term box) at the tuned length.

(Place the opening into the muffler chamber at the point that PipeMax tells you to; no?)

Adam
You’re going to need more than one set of mufflers to quiet a car down efficiently.


Years and years ago, onna the mag's did an article titled something like, "Q-Ships"! East coast BIG cars here..

The article was about Sat. late night street races for CASH.

The cars were early Buick Deuce and a Quarters that had been cammed and whatever. Suckers were so long in the back overhang that they would hook up on spit!

AND the article went on to say that many a SBC powered car got to hand over the $500 or so bet after losing!

To stay with the, "Q-Ship", name, they had two big MOPAR hemi mufflers down each side to make them sound like stock!!

And we all know that a worked over 455", (or larger), Buick in any vehicle is dammed near King of Torque!!

This musta been a hoot late night street racing, illegal or not!

I wonder if, "Aceshigh", knows anything about this since he was raised in Chi-Town because I figure what was out east would carry-on over into the, "Windy", is all....

I do remember that I took a ride in a stock early '70's Deuce and a Quarter from Mexico, MO to the NE corner of Indiana one Thanksgiving Holiday and the big car ran like a, "scalded dog"! Fucking STOCK!!!

pdq67

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