High Flow Quiet Exhaust

Strictly Attitude

Strictly Attitude

solid fixture here in the forum
Ok the Chevelle has shorty mufflers to a dual 2.5" h-pipe with flowmaster 40 or super 44 mufflers. I plan to convert this to a x pipe for starters but I really want the quietest I can go with out making a large performance sacrifice. Is this possible to be accomplished or is this going to end up being a compromise thing. I mostly drive the car to work and back and miss being able to hear the radio in the morning. I would go as quiet as I could get it and thought of putting the 307 emblems on the side and stripping off the SS emblems and changing the license plate to say Napping.
 
EXHAUST NOISE is the result of UN DAMPED VIBRATION, or failure to control, dissipate and absorb the individual exhaust pulse strength.
the use of an (x) pipe or ideally two (X) pipes allows you to split , equalize and dissipate the individual exhaust pulse from a single cylinder into two separate exhaust pipes and effectively double the cross sectional area , thus reducing both strength and velocity of the gases.
Ive found a multi stage approach, to destroying and dissipating the exhaust pulse strength is very effective, Id run an (X) pipe behind the header collectors
H pipe X pipe (2).JPG

Dual_X_PipeExhaust01.jpg

h-pipes are no where near as efficient or effective at equalizing or reducing individual, bank to bank exhaust pulse strength,or reducing the restriction to exhaust flow, as a similarly placed (X-pipe )
if you have the room two (X-PIPES in sequence have been repeatedly been tested,
and repeatedly found to provide a minor but measurably better result in increasing cylinder scavenging and a mellower exhaust sound
your not going to see any huge gains from either configuration, but a single (X-pipe generally produces a bit better and a wider torque curve ,
and two x-pipes in series is not all that rare recently even on the higher end performance cars
dualxmod.jpg

INSTALLING AN (X) PIPE IN THE EXHAUST ON A DUAL EXHAUST CAR
80.1280.JPG

EXFLOWZ4.jpg

keep in mind that a properly designed exhaust system and headers goes a very long way towards increasing the efficiency of the intake manifold and head flow , and remember that the better the heads and the more effective the exhaust scavenging the less duration the cam used will require!
what goes in, needs to flow out with near zero flow restriction
tti_3_x.jpg

http://www.summitracing.com/parts/wlk-17553/overview/
ex30870.jpg




http://www.dragzine.com/tech-storie...ffler-design-and-sound-absorption-strategies/

http://www.onallcylinders.com/2012/06/29/sound-advice-a-quick-guide-selecting-right-muffler/

http://www.superchevy.com/how-to/exhaust/0505phr-exh/

http://www.autoanything.com/exhausts-mufflers/flowmaster-muffler-comparison-guide

http://www.pontiacstreetperformance.com/psp/exhaust.html
flowre1.jpg

flowre2.jpg


that fed immediately into a muffler like this, with a second internal (x) pipe with perforations that dissipated the pulse strength AND further blends ,splits and separates the pulses, each (x) effectively reduces the individual pulse pressure wave
xmuff.jpg

then into two mufflers like this with tail pipes extending out past the bumper
http://www.summitracing.com/parts/wlk-17219/overview/
READ THRU THESE LINKS
viewtopic.php?f=56&t=1503

viewtopic.php?f=56&t=1166

viewtopic.php?f=56&t=5001&p=42468&hilit=mufflers#p42468

http://www.onallcylinders.com/2012/06/29/sound-advice-a-quick-guide-selecting-right-muffler/

http://www.onallcylinders.com/2014/...llation-vs-flowmasters-delta-flow-technology/

http://www.onallcylinders.com/2012/08/14/video-exhaust-x-pipes-vs-h-pipes/
 
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usually if your pipe diameter is too big, you will get unneeded resonance, also, the use of x pipes as grumpy pointed out does alot to eliminate both overall noise of the exhaust and the annoying drone that can occur when cruising
 
Thats a good idea grumpy I like the whole double x pipe idea I read about will have to break out the measuring tape. I just googled the undercariage the double x is gonna be out of the question. :( See if it will fit under there the other plan was x-pipe then two resonators into the mufflers. I also want to get away from the chambered muffler design as there seems to be a general sensus they drone more. I must say the drone right now is absolutely the worst right at highway speed. This is pretty much how my exhaust is except shorty headers because my father had pypes side pipes on the car for a while when he owned it.
 

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gm a body 3,5" exhaust ,x pipe four 3,5" straight tru mufflers with tail pipes
and is a very quiet
 

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There is only 1 series of Muffler that I have used to meet your Criteria John.
Walker Super Dynomax Oval Retangular case mufflers.
Popular with Pontiac 400-455 guys with GTO & Firebird Trans Am.
2-1/2- 3 " Dual systems.
3 inch Will support 10- high 9 second cars Big block.

Quiet almost near stock.
Throaty when onhe gas hard.

There was a Pontiac only muffler shootout 20 years ago.
Walker Super Dyno Max gave same 1/4 mile ET adls Flowmaster 2-chambers.
 
There is only 1 series of Muffler that I have used to meet your Criteria John.
Walker Super Dynomax Oval Retangular case mufflers.
Popular with Pontiac 400-455 guys with GTO & Firebird Trans Am.
2-1/2- 3 " Dual systems.
3 inch Will support 10- high 9 second cars Big block.

Quiet almost near stock.
Throaty when onhe gas hard.

There was a Pontiac only muffler shootout 20 years ago.
Walker Super Dyno Max gave same 1/4 mile ET as Flowmaster 2-chambers.
 
87vette81big said:
There is only 1 series of Muffler that I have used to meet your Criteria John.
Walker Super Dynomax Oval Retangular case mufflers.
Popular with Pontiac 400-455 guys with GTO & Firebird Trans Am.
2-1/2- 3 " Dual systems.
3 inch Will support 10- high 9 second cars Big block.

Quiet almost near stock.
Throaty when onhe gas hard.

There was a Pontiac only muffler shootout 20 years ago.
Walker Super Dyno Max gave same 1/4 mile ET as Flowmaster 2-chambers.
Click to expand...
Will look into these have heard good things about the borla XS mufflers also but I think I would have to run resonators with them to get them where I want them so the walkers would probably be the better option. I did find the borlas for dirt cheap on a site and they were the long ones also.

found this
http://www.midatlanticperformance.net/p ... 321.0;wap2
 
Borla XR Series is a Full Race Muffler.
Be my choice 9-seconds & Faster.
4" or 5" inch duals.
Fit Classic Musclecars & 5.0 Stangs best.
Target HP 1,000-2,000 +.

No one here is running that fast yet.

Walker Super Dyno Max is almost Whisper quiet.
Been used on many 10-second ET Pontiac 428-455 Race machines.
 
dynomax rattle with radical cams and true duals

dynomax recently introduced a valved exhaust muffler that shows some promise as it will reduce any reversion pulse strength
THE dynomax mufflers with the valve have a reputation for rattling like a tin can full of marbles with a radical cam and true dual pipe muffle exhaust, the rattle is the result of individual exhaust pulse flow from individual cylinders reaching and rapidly forcing an opening in the one way exhaust flow gate valve, that opens as the exhaust volume of gas flow hits it and forces it open,then momentarily wanes (is reduced) the gate closed as the spring forced it closed,(SEE PICTURE) resulting in the rattle as the exhaust flow mass is far from consistent.
placing two 3" x pipes in sequence seems to work well at both mellowing the exhaust note, and increasing the exhaust scavenging of the cylinders as it blends and smooths out the exhaust flow by allowing the individual cylinder pulse strength to dissipate rapidly, the first (x) reduces flow restriction, the second allows the exhaust pulse to run into itself further disrupting the individual pulse strength, obviously the length, or distance between the (X) pipes and mufflers, diameter and length of the exhaust pipes and engine cam timing and displacement will effect your results
here above is a rather typical (X) pipe,
x1.jpg

exhaustpressure.jpg

the exhaust pressure pulse splits its flow and significantly reduces back pressure as the pulse enters the (X) as its effective cross sectional area almost DOUBLES , dropping that back pressure almost in half at that point, which usually increases cylinder scavenging potential of tuned headers, and increasing higher rpm power if used, and usually reducing noise as the frequency is disrupted, inducing a mellower tone.



Dynomax-VT-Cutaway-2-300x246.gif



mounting a dual (X) PIPE tends, to reduce the individual exhaust pulse flow mass and energy, the (X) pipe in front of the muffler tends to greatly reduce the individual pulse strength and velocity by dividing and slowing the flow as the internal cross sectional area rapidly increased and even out the flow as it hits the flow gate, having two in a series works even ore effectively.
xpipehel.png
 
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The original Walker Super Dynomax Mufflers.
No Gizzmo trap door valves.
The Long case 21"-24 " length oval retangular mufflers.
Won't fit any Vette.
But do fit 1967-81 Camaro Firebird Trans Am.
1964-74 GTO & Chevelle.
1959-78 Full size Pontiac & Grand Prix.
Installed you will only hear the Roller Rockers, Drive accessory belts turning, and the 5-cycle Camshaft in action.
20 feet away you would be hard pressed to tell the car is running.
Only Summit Racing carries the original Super Dynomax.
Backfire & explosion proof like a Flowmaster Race muffler.

Cost effective also.
Won't take $500-1,000 to buy & install other systems.
 
yeah the whole trap door thing not sold over complicating it I feel sounds like something to go wrong or sound annoying. Even though my r6 had a flapper built into the exaust to tune for more low end power and torque. But it was actuated to move but it was also a 16000 rpm redline from the factory. I accuse it for making cars seem slow to me. Cheapest way to go quick and fast no feeling like dragging knee on an off ramp at 80mph. Hence why I do not own it any more. I was making it into a track only machine because of my bad habits. Never was into wheelies or stoppies or the other stupidity. But I knew it had to go cause on the road it was only a matter of time at least on the track you don't have to worry bout cars. But with the little one I opted to get rid of it all together.
 
Thanks guys. Timely as my new toy has serious drone going on. I only wish I could find somebody with a Catalina running with 2 "X" pipes and 2 Walker Super DMs.
 
Walker Super Dynomax Oval cased mufflers.
Super Quiet Richard.
Drag Raced proven in past in High Performance Pontiac Magazine back in 1991. Tested on a 11-second ET daily driven 455 Poncho Station Wagon.
Have the magazine still.
No X-pipe or other Gizmos needed.
 
chromebumpers said:
Should install headers or would It be back to being loud again?
Click to expand...
Headers to to Fit the Catalina is a problem.
Not a GTO Or Firebird Trans Am.
A few sets were made by Nunzi Right.
He retired and closed up shop.
When you find them to Fit the Big Catalina the Seller may want $1,000-3,000.
Things don't come inexpensive for Hi Po Race Pontiac .
Your not Racing so Factory Daul Exhaust will suffice Nicely.
Aftermarket Reproduction Big Car Factory Hi Flow exhaust manifolds made.
Work nice on the street daily driving .
No leaks. Whisper quiet.
A few have used Drag Racing to High 11's.
 
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