Restrictive Mufflers

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Interesting Ive got a tti sys in my 68 Barracuda with the turbos but there to loud for me. Its funny I was going to run a new set of ultra flows for the track but not now.
 
I'd bet they have little or no wave cancellation effect which would leave lots of drone and loud sound. Turbos are wave cancellation chambers, so are chambered mufflers, hell even glass packs are to a certain extent. The space around the tube is doing work, the material around the tube is doing work, both to cancel and dampen noise.
 
MOPEkidD-3 said:
What's the rest of your setup and plans for the future? Full 2.5" exhaust with manifolds requires custom-bent downpipes or ones from TTI (also included in full system). If you are planning on putting full-length headers on anytime soon I would hold off on doing the exhaust until you get them and do the entire system front-to-back at once.

Hey VOETOM have you flow tested one of these by any chance?
3.jpg

http://www.classicchambered.com/index.html

I have a pair of the longest 2.5" "powersticks" on my '70 Duster and I love the sound, about as raw as it can get...
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I have a set of these on my van, man are they LOUD when you
romp on it.
My 400 makes them scream!
You can see it here.
http://www.forabodiesonly.com/mopar/showthread.php?t=254323
 
GTS Registry said:
How old were those Accurate mufflers?? I have been told there are a different style with newer vs. older mufflers. I bought mine in 2000 and they look like your cutaway mufflers when I cut mine open too. I replaced those Accurate mufflers with a pair of DynoMax Super Turbo mufflers. With NO other changes, my GTS ran a full second faster in the 1/4 mile and picked up almost 4 MPH! I have since replaced the Accurate 2 1/4" system with a TTi 2 1/2" system X pipe with Ultra Flo mufflers. That was worth another .2 in the ET and 1 1/2 mph.
Click to expand...

I think I bought the mufflers around the same time as you, 2001 maybe.
Your new mufflers took a full second off your et? Thats huge. How loud were your Super Turbos? How loud is it now with the Ultra Flos? I'm going to change my whole exhaust system this winter and I'm trying to get input on which mufflers to use.
 
VOETOM said:
Mope, we have not but I bet they pass a lot of air through them since there are not many restrictions. If they have 2.5" center tubes, they will work well. I have heard some chambered Camaros and man, even stock, they are loud!!!
Tom
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Lol yeah it sounds like an explosion is going off behind me every time I step on the gas. Surprisingly not bad inside the car though, they really don't drone as much as you'd think but I do have an X-pipe which smooths it out a bunch. It is a bit much on long trips though gotta get some extra resonators for the tailpipes. They are 2.5" (or whatever pipe size you have) straight-through so there's basically no restriction except for the louvers in the inside section.

As far as Turbos vs. Ultra Flos, Turbos are very quiet almost as quiet as most OEM mufflers IMO and they don't have much tone to them. Ultra Flos have a nice tone and a bit louder but still not obnoxious by any means.
 
Best flowing mufflers are the warlocks and then the Hooker maxflows then the ultraflows.
 
Warlocks with the caps off do pass some serious gas.
Actually, the polished UltraFlos have a larger cores than their inlets and outlets so they pass over 100% of the air that a straight pipes can flow, at least the offset offset ones. Straight through flow even more.
The Hookers are likely very similar!
Not seen any Warlocks for a while but they were/are a cool idea.?
Tom
 
Wow, glad we did such a thorough job testing back then. :)

And, even as late as 2012, we still saw similar traits with other cars as they changed from restrictive mufflers to higher flowing ones.
Tom Hand
 
Wish I could find the old article where someone tested the original turbo mufflers. Seems to me a SINGLE corvair turbo muff on a 300 hp V8 lost about 15 hp under open pipes.
 
I'd like to see this type of comparison on engines with bigger cams & heads that are more sensitive to exhaust scavenging and backpressure. I'm assuming the difference would be more pronounced because the ability of the cylinders to fill on a higher-overlap cam hinges more on how well the inertia of the air/fuel moves past the valves when they are open rather than the physical pumping action of the piston pulling and pushing the air/fuel in and out.
 
bobscuda67 said:
I think I bought the mufflers around the same time as you, 2001 maybe.
Your new mufflers took a full second off your et? Thats huge. How loud were your Super Turbos? How loud is it now with the Ultra Flos? I'm going to change my whole exhaust system this winter and I'm trying to get input on which mufflers to use.
Click to expand...

The Super Turbos were only slightly louder than the Accurate mufflers-the most noticable difference was at wide open throttle. The Ultra Flos are even more free flowing than the Super Turbos, but I changed the entire system with the Ultra Flos. If your looking for performance AND cruising noise comfort, I would stay with the Super Turbos. Take those Accurate mufflers to the scrapper!
 
Got dynomax ultra flows on my duster. TTI headers, 2 1/2 alluminumized system w X pipe. Don't seem real loud in the car but everyone tells me it sounds like a freight train coming. 450 HP roller 340 sounds like a big block. I don't mind loud. That's just me
 
I thing I'm gonna try the Dynomax VT's. I'm also going to install 2 1/2 mandrel x pipe from the manifolds to the mufflers. I'll just reuse the 2 1/4 Accurate tailpipes.
I got my mini starter installed today and was looking at making my own head pipes. It looks like there's room between the bar and starter for a 2 1/2 pipe without dimpling it.
 
67 Dart, I should have that article. I am pretty sure it was David Vizard's 70's article where he fixed up a cat. conv. for a Monza and also tested some mufflers at the same time.
I'll try to get it for you and post it.

UPDATE: 67, I went through my stuff and found all the way back to the 1973 Hot Rod muffler test. I also found the Vizard article about converters but it was not the one I remembered. You know, we mad a single system for the wagon and tested lots of mufflers on it; could that have been the one you are remembering?

Tom
 
There are a lot of excellent points in this thread regarding mufflers and balancing flow with sound qualities. The first poster pictured a muffler design we used that was about 10 generations back (14 years). It served the market well with a reasonable exhaust flow/exhaust note and lasted for many years without coming apart even when being abused. Our most recent ACM-912 design (pictured) are for those wanting excellent flow and sound control that sounds close to factory. The ACM-912 mufflers have replaced these earlier units. For those wanting all out performance we have the "Stainless Magnum" series muffler which is similar to the Ultraflow and Magnaflow straight through designs but these , like most similar designs can resonate under load and certain rpms. A few issues that face those of us in the exhaust industry is marketing a muffler that is not too loud in the passenger compartment, flows reasonably well and fits properly.
 

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MOPEkidD-3 said:
What's the rest of your setup and plans for the future? Full 2.5" exhaust with manifolds requires custom-bent downpipes or ones from TTI (also included in full system). If you are planning on putting full-length headers on anytime soon I would hold off on doing the exhaust until you get them and do the entire system front-to-back at once.

Hey VOETOM have you flow tested one of these by any chance?
3.jpg

http://www.classicchambered.com/index.html

I have a pair of the longest 2.5" "powersticks" on my '70 Duster and I love the sound, about as raw as it can get...
Click to expand...

I put a set of these on my Tundra, I was very pleased with the sound. It can get loud if you really get on it, but just cruising around you here a nice constant rumble. Tundra is the 5.7L. They are advertised as chambered but if you look down it its a straight pipe, you can not see any of the outside crimping from the inside. Still like them though. Im running straight headers on my duster but I am really considering a set of these for it.
 
Here's what mine look like,been on the car 25 years and 4 or 5 engines. They sound awesome..
 
Great thread. Having at least some hard facts goes a long way for those that want to evaluate with something more than hype.

Flow Bench Test. L & M Machine Shop, PA.
Using a Superflow 600 bench,nominal 400 cfm.
Paid for by mwaa as Miss Piggy would say.

Accurate Ltd A-body Performance Muffler, purchased June 16, 2004.
2.25" inlet and outlet, offset-center, 16" Body
Flowed 228 cfm *

Walker/Dymomax SuperTurbo 17734
2.5" inlet & outlet, offset-offset, 14" Body
Flowed 271 cfm *

*Tests were done at 28" of H20. (assumeing I copied my own notes correctly).

Attempting to compare these results to Vizzard's tests of 'turbo' type mufflers has a couple of challenges. One is that we don't know the shape of the inlet connection he used. The other is that his tests were done at 25" of water.

The first place I saw Vizzard's test results was in Performance with Economy SA Design, 1981, 1988. But shows up again in How to Build Horsepower Vol. 1.

I also have note on my spreadsheet that says a straight length of 2" pipe will flow 353 cfm. That has to be qualified because I don't have the length, conditions or source. When I find those notes, I'll post back or edit.

My take away from the articles and tests is that a dual 2.25" system is generally not the restriction on street car with v-8. It's the mufflers. The Accurate mufflers flowed well for a 2.25" muffler, but a 2.5" would be better especially for bigger displacement engines and higher rpm goals. Of course, this all ignores the fact that in reality the flow is not continuous but pulsed, but that's getting off topic.
 
Originally Posted by furyus2
who makes a nice 2 1/2" exhaust for our a bodies? I want to do this right the first time, but i want it to look close to stock.

tti
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Accurate also makes a 2.5" system.

Accurate uses the factory locations for the muffler hangers. TTI does not.
TTI uses the factory type tailpipe hangers. Accurate does not.
Accurate offers a special fit tailpipe for the 67 fuel tank based on the 383 dual exhausts available that year.

Note: Some of the above information may be dated. It's not something I've stayed on top of, but I think it is still correct.
 
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