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General => Archive & Library (Read Only) => Topic started by: V8Demon on April 17, 2008, 11:52:18 AM

Title: Muffler flow tests and Exhaust theory
Post by: V8Demon on April 17, 2008, 11:52:18 AM
http://www.allfordmustangs.com/Detailed/70.shtml

Quote
According to the recent Mustang poll, more than 1/2 of voters would or did spend their first modification dollars or exhaust. Easy decision on what to do, but the real decision lies in whose exhaust to buy. With more than a dozen companies making cat-back systems alone for Mustangs, the trying to figure out how it will work with your combination can be overwhelming. Don't fret we're here to help.

We obtained 10 different after-cat exhaust configurations for 1987-1993 Mustangs (1979-1986 can use the same setups if converted to true dual exhaust). The goal is to illustrate key points of each system and explain how it worked on the test car to help you make an informed decision on what system might be best for you.
Title: Muffler flow tests and Exhaust theory
Post by: JeremyB on April 17, 2008, 02:18:50 PM
Nice.

I wish they had used an SPL meter for a quantitative measurement of sound. Noise is an important figure of merit for me.
Title: Muffler flow tests and Exhaust theory
Post by: Red_LX on April 17, 2008, 03:24:07 PM
Is the Quiet Thunder the system that has the removable baffles for the exhaust tips?
Title: Muffler flow tests and Exhaust theory
Post by: V8Demon on April 18, 2008, 08:39:01 AM
I have no idea....One thing that could have been done was to note the manufacturer's part # for each respective setup.  A search on Bassani's website showed no results for a foxbody car concerning the quiet thunder system.
Title: Muffler flow tests and Exhaust theory
Post by: Cougar5.0 on April 18, 2008, 09:09:02 AM
Here's my favorite muffler shootout article - just the all-important comparison tables ;)

(http://i43.photobucket.com/albums/e360/Domeskull/mufflercomparesht1.jpg)
(http://i43.photobucket.com/albums/e360/Domeskull/mufflercomparesht2.jpg)

And the dB levels for Jeremy:
(http://i43.photobucket.com/albums/e360/Domeskull/mufflerdecibels.jpg)
Title: Muffler flow tests and Exhaust theory
Post by: V8Demon on April 18, 2008, 10:41:01 AM
Perhaps you can enlighten me as it seems you have the actual article.....I've seen those results before, but am leery about them because I am unsure what other changes were taken into account on the exhaust system.

http://www.foxtbirdcougarforums.com/showthread.php?t=17505

With the other test it's shown the same headers and X-pipe were used throughout.  With the "Muffler Shootout I've never heard if this was the case and if so what components were used.

Quote
The test car is a mildly modified 1990 LX 5L (details here). The rest of the exhaust for the testing was comprised of MAC 1 5/8" EL headers into a Bassani 2.5" offroad X-pipe. Weights were included where possible. OK, now let's get started.


I would very much like to see that info concerning the magazine test if it's available.  It would be appreciated.;)

The ultimate test would be the mufflers on some type of flow bench with as little piping as possible to show true flow #'s of the mufflers themselves.
Title: Muffler flow tests and Exhaust theory
Post by: Cougar5.0 on April 18, 2008, 11:36:07 AM
I've read the entire article and the test was a remove and replace on the same car - I can't find the entire article now though as I had a link to it but it's dead. I would much rather have them test mufflers on a 370 RWHP car than a 225 HP 14 second car due to differences may be more visible due to higher airflow. Comparing ET's is not that scientific if you ask me. Flow rates are available and straight-through like the Magnaflow flow best(?), but in the real world with exhaust pulses causing resonances in the muffler, simple flow rates may not tell the whole story. This is not the first time I've seen a test where no muffler gives less HP - there can be issues when a sudden change from a closed pipe to free-air occurs. Also see the AFR tuning comment in the article review I've posted below. I've seen some reputable racers on Hardcore5.0 claim to go the same ET with a muffler versus without. These are typically high-HP cars too.

OK, I found another source for the article's info with a review of the methodology too! It's just one man's opinion, but I think it's a good one:

Quote from: "Steve A."

The best muffler comparison I've seen to shed light on available choices based on that criteria was in the December 2002 5.0 Mustang and Super Fords magazine. 15 pairs of performance mufflers were tested on a highly-tuned, naturally-aspirated, EFI 306 Mustang making about 370 RWHP. Peak power is in the mid-6000 range, peak torque mid-5000 range. Tests were run back-to-back in a single day on Rick Anderson's dyno (Anderson Ford Motorsports). Horsepower, torque, and various sound levels were recorded in the most consistent manner possible for valid comparison. Four pulls were made with each pair of mufflers, and an average used for the reported numbers. Sound was measured with a decibel meter at idle, at 2000 rpm light-load cruise, and then at wide-open throttle maximum.

None of the mufflers produced hugely-different power results, ranging from 366.3 RWHP to 374.2 RWHP, and 330.1 lb./ft to 334.0 lb./ft. torque.

There were, however, a lot of differences in sound levels produced...both in quantity and subjective quality. Sometimes the loud mufflers produced more power, and sometimes they didn't. I've listed the mufflers below and the suggested retail price EACH as given in the magazine (rounded to even dollars). In the brackets with the price, I've indicated their construction: SS for stainless steel, AS for aluminized steel, and MS for mild steel. Next is the measured sound-level results in decibels, followed by power numbers (to compare relative efficiency). Re: the decibel numbers...the first number after the muffler name is decibels at IDLE, the second number is 2000 rpm CRUISE decibels, and the third number is WOT decibels. RWHP & RW torque are listed last. (Note: OMS means "off the sound meter's scale... too loud to measure):

NO muffler ($free!): 91/103/OMS/365.2 RWHP/330.1 RWT
Bassani QT ($186 SS): 83/96/120/372.0 RWHP/333.5 RWT
Bassani Real Street ($186 SS): 84/96/OMS/373.7 RWHP/333.8 RWT
Borla XS ($130 SS): 80/90/110/373.3 RWHP/332.6 RWT
Borla XR1 ($168 SS): 83/96/118/370 RWHP/334.0 RWT
Dynomax Ultra Flo ($80 AS): 83/94/113/369.4 RWHP/333.2 RWT
Edelbrock RPM ($179 SS): 84/94/118/370.9 RWHP/331.3 RWT
Flowmaster 50 series SUV type ($135 MS): 82/93/115/369.4 RWHP/331.8 RWT
Flowtech Afterburner ($43 AS): 86/94/115/372.3 RWHP/330.1 RWT
Flowtech Terminator ($59 AS): 86/94/119/369.5 RWHP/331.3 RWT
Flowtech Warlock ($75 MS): 83/92/112/366.3 RWHP/325.3 RWT
Hooker Aerochamber ($69 AS): 87/94/114/372.1 RWHP/330.4 RWT
Hooker MAXflow ($69 AS&SS): 80/90/120/373.5 RWHP/333.0 RWT
MAC Flowpath ($80 SS): 87/98/119/372.3 RWHP/331.5 RWT
Magnaflow ($84 SS): 82/91/114/372.8 RWHP/332.5 RWT
SpinTech ($80 AS): 87/97/116/371.6 RWHP/332.2 RWT

Rick Anderson wisely points out in the article that (as always) you shouldn't look only at peak HP/torque figures but rather at AVERAGE power production figures within the engine's powerband. Best in that regard was the (very loud) Bassani Real Street, followed by a virtual four-way tie between the Magnaflow, both Borlas, and the Hooker MAXflow.

FWIW in scientific procedure commentary: Because the open-pipe version was lowest in power, my opinion is that the car was well-tuned for mufflers and the injectors went slightly lean at max rpm when the exhaust was opened up. That would suggest that a couple of the most open, high-flowing mufflers MIGHT have made a few more ponies on top with the A/F optimized for them. They're all so close, though, that this is nit-picking.

It's worth noting that there's a significant weight difference among these mufflers, ranging from 6 lb. for the DynoMax to 16 lb. for the long, 3 chamber Flowmaster. That's up to 20 lb. weight difference for 2 mufflers!

The "quality" of the exhaust note produced is impossibly subjective to quantitatively express...yet every gear head can listen to different exhaust combos and...more often than not... agree on which ones sound "good" to the performance enthusiast's ear. 5.0 magazine picked the Magnaflow, Bassani QT, and Edelbrock RPM as having the "sweetest" performance notes. FWIW, this agrees with my own casual observations.

After running all this data combined with my own experiences through my red-neck, highly-biased, opinionated, don't-confuse-me-with-the-facts-because-my-mind's-already-made-up cerebral computer, I interpret the outcome as two winners (based on our originally-stated criteria):

If you want the quietest muffler you can get without suffering a performance penalty, the Borla XS wins hands-down. The ability to make power while generating only 110 db at WOT is amazing. It's 90 db cruise is also the quietest, as is its 80 db idle. Bonus is it's one of the lightest at 7.5 lb. T'aint cheap at $130 each, but the stainless Borla offers undisputed high quality with a nearly-forever warranty. Their sound reminds me of the stock, "factory muscle car" sound of the 60's. Conservative but classy.

The Magnaflow offers great value, high quality, high performance, and sweet music without the mind-numbing drone or obnoxious bellow. Only $84 each gets you shrink-wrapped, flawless stainless steel that is polished so beautifully that it will make you sad to hide them under your car. At 10.5 lb. they're still on the lighter end of the spectrum. They're only 1 db louder than the Borla XS at cruise speed, and only 2 db thumpier at idle. They open up "just enough" at WOT (IMHO) to sing a well-controlled but exuberant horsepower sonata. Fortissimo passion without pain. Even though 4 db. louder than the Borla at WOT, they're still on the low db side compared to the others in the test. I've never heard anyone complain about the "quality" of the sound from Magnaflows, and only a couple complaints about "not loud enough," (mostly from 2-chamber Flowmaster aficionados, lol).

Either of these choices SHOULD be run with an H or X pipe crossover. This will provide both better performance and optimum sound control. Either COULD be run with cats which would subdue their mildly-sonorous personalities even further.
Title: Muffler flow tests and Exhaust theory
Post by: V8Demon on April 18, 2008, 01:16:23 PM
Quote from: the article
Because the open-pipe version was lowest in power, my opinion is that the car was well-tuned for mufflers and the injectors went slightly lean at max rpm when the exhaust was opened up


Quote from: me
it would seem the exhaust system was optimized to be used with a muffler and not wihout as evidenced by no muffler showing the lowest HP rating.


Same end result in that particular case of no muffler.....

Thank you.  I've never seen the full article and what you added was helpful!

Just like everything else, your exhaust system is a compromise....

http://www.carcraft.com/techarticles/header_basics/index.html
http://www.chevyhiperformance.com/techarticles/0803ch_dynomax_exhaust_system/index.html
http://sbftech.com/index.php/topic,7758.0.html
http://sbftech.com/index.php/topic,4825.0.html
http://www.maxracesoftware.com/pipemax36xp2.htm
Title: Muffler flow tests and Exhaust theory
Post by: 88BlueBird on April 18, 2008, 01:25:58 PM
Those Borla XS's used in that exact Anderson shootout are now are my car :)  I bought them years ago from Rick Anderson for very cheap....it's a small world really when it comes to cars.
Title: Muffler flow tests and Exhaust theory
Post by: Cougar5.0 on April 18, 2008, 02:08:00 PM
Sweet! That's a cool follow-up to the article!

I'm presently going to remove my mufflers to maximize my power levels :hick:
Title: Muffler flow tests and Exhaust theory
Post by: daboss351 on April 18, 2008, 02:31:27 PM
Wish they would do the SLP loud mouth!
Title: Muffler flow tests and Exhaust theory
Post by: Cougar5.0 on April 18, 2008, 02:38:58 PM
You can usually guesstimate by what type it is (chambered, straight through etc...), diameter & by listening to clips someone might have posted online.
Title: Muffler flow tests and Exhaust theory
Post by: daboss351 on April 18, 2008, 02:40:29 PM
yea
theres a HUGE muffler comparo for the 03/04 cobra. Vids and sound clips for TONS of header, h/x pipe, and cat back combos.
Title: Muffler flow tests and Exhaust theory
Post by: V8Demon on April 18, 2008, 02:42:28 PM
did ya take the mufflers off yet?!:crazy: :hick:
Title: Muffler flow tests and Exhaust theory
Post by: Cougar5.0 on April 18, 2008, 05:44:32 PM
Yep, brand new Magnaflow stainless - cut 'em off with a chainsaw. Now gonna cut 'em in half and use 'em as planters on the side of my metallic portable home - yehaw! They won't rust like my home! My grandpaw would be mighty proud! :hick:
Title: Muffler flow tests and Exhaust theory
Post by: Red_LX on April 18, 2008, 09:50:12 PM
The 5.0 Mustang mag's sound tests for the Hooker Maximum Flow are pretty dead on....one of the quietest at idle and one of the loudest at WOT. ha.
Title: Muffler flow tests and Exhaust theory
Post by: V8Demon on April 19, 2008, 09:29:00 AM
A-HA!!!!!

http://www.broaderperformance.com/muffler%20flow%20test-A.htm
http://www.a-1performance.com/flow.htm

And perhaps the best article I can think of on this subject:  http://www.popularhotrodding.com/enginemasters/articles/hardcore/0505em_exh/index.html
Title: Muffler flow tests and Exhaust theory
Post by: Cougar5.0 on April 19, 2008, 12:36:28 PM
The two lists use a differerent water drop 15" versus 20.3" - too bad it makes comparision difficult. The one obvious thing here (and this has been proven out at dragstrips), Flowmaster mufflers flow like puppies & cost HP.

Here is a more complete list of the first flow rates you listed. Note the Magnaflow don't flow as you might expect for a stragiht-through - but I'll take a HP test on an actual car anyday as the final arbiter.

All tests via an independent lab
All tests @ 15” wc

2 “ Straight Pipe 283 CFM
2 ¼ “ Straight Pipe 365 CFM
2 ½ “ Straight Pipe 521 CFM

2 ¼” Typical Bent tailpipe 268 CFM
2 ½” Typical Bent Tailpipe 417 CFM

2 ¼” Inlet/Outlet_ Glass Pack Tips- No Louvers- Smooth 274 CFM
2 ¼” Inlet/Outlet- Glass Pack Tips-Louvered 133 CFM
Same as above set for reverse flow 141 CFM
2 ¼” Cherry Bomb 239 CFM
2 ½” Cherry Bomb 294 CFM

2 ½” Inlet/Outlet Dynomax Super Turbo 278 CFM
2 ½” Inlet/Outlet Ultraflow Bullet 512 CFM
2 ½” Inlet/Outlet Gibson Superflow 267 CFM
2 ½” Inlet/Outlet Flowmaster ( 2 Chamber) 249 CFM
2 ½” Inlet Outlet Flowmaster ( 3 Chamber) 229 CFM
2 ¼” Inlet/Outlet Thrush CVX 260 CFM
2 ½” Inlet/Outlet Maremount Cherry Bomb 298 CFM
2 ½” Inlet/Outlet Hooker Aero Chamber 324 CFM
2 ½” Inlet/Outlet Hooker Max Flow 521 CFM
2 ½” Inlet/Outlet Borla Turbo 373 CFM
2 1/2" Inlet/Outlet Magnaflow 284 CFM


Standard OEM 2 ¼” Inlet/Outlet 138-152 CFM
Standard OEM 2 ½” Inlet/Outlet 161-197 CFM

The madrel bending of the pipes done by aftermarket exhaust companies is good for 2-4 h.p. depending on the severity of the stock bends. Most local exhaust places dont have a mandrel bender so changing the pipes out doesnt do anything if pipe size it not increased.
Title: Muffler flow tests and Exhaust theory
Post by: V8Demon on April 19, 2008, 01:11:25 PM
Quote
Flowmaster mufflers flow like puppies & cost HP.


And this along with the fact they turn into solid rust in 6 months is why I have not and never will run them on a vehicle.

Quote
2 ½” Inlet/Outlet Borla Turbo 373 CFM


I wonder if this is the standard or the XR-1.....

Quote
Most local exhaust places dont have a mandrel bender


I know a couple that do ;)
Title: Muffler flow tests and Exhaust theory
Post by: james cassity on April 21, 2008, 12:51:33 AM
i gotta feeling this thread might get lost.

can conclusions be consolidated to one post so i can add it to my diy link?

also,,, i agree,
I would also like to see flow numbers on a bench with little or no pipe.
Title: Muffler flow tests and Exhaust theory
Post by: V8Demon on April 22, 2008, 12:00:16 AM
In super simplified terms:
Velocity and scavenging=Good.
Backpressure=Bad
Flowmasters=Suck


The muffler in an exhaust system can be used just like exhaust pipe to extend the collector and add to wave pressure tuning.
Title: Muffler flow tests and Exhaust theory
Post by: Carpimp1987 on April 22, 2008, 03:02:23 AM
USED Raven mufflers they don't make them anymore but i promise you will have a one of kind mean sounding ride.

Next i would vote SLP Mufflers http://www.americanmuscle.com/slp-power-flo-mufflers.html
Title: Muffler flow tests and Exhaust theory
Post by: V8Demon on April 22, 2008, 10:06:07 AM
That post has ABSOLUTELY no technical input to add If you're going to post about a certain muffler, you could have found an independent test of it with technical data OR perhaps asked if anybody knew anything about it....Please stop post whoring, especially in a tech thread.....
Title: Muffler flow tests and Exhaust theory
Post by: Cougar5.0 on April 22, 2008, 11:12:37 AM
I hear you - "this is my favorite muffler" is hardly helpful to this thread.

I'd be willing to delete all of my non-contributing posts in this thread (including this one) so it can be made into a sticky without to many BS posts.
Title: Muffler flow tests and Exhaust theory
Post by: Cougar5.0 on April 23, 2008, 12:01:02 PM
OK, check out this thread -> Flowmaster JUNK mufflers (http://"http://speedtalk.com/forum/viewtopic.php?t=10580&postdays=0&postorder=asc&start=0")

...makes me glad I chose the 18" Magnaflow - BigJoe said they made more power than the 14" magnaflow and a lot more than ClogMasters.

Glad this got sticky status too!
Title: Muffler flow tests and Exhaust theory
Post by: thunderjet302 on April 23, 2008, 12:58:56 PM
I use Flowtech Afterburners on mine. All they are is pipe into big hollow chamber and pipe out of big hollow chamber :hick:
Title: Muffler flow tests and Exhaust theory
Post by: 88TurboCoupeman01 on July 30, 2008, 10:46:22 PM
Is there anyone who has a chart for these mufflers for the Turbo Coupe.
Title: Muffler flow tests and Exhaust theory
Post by: Chuck W on July 31, 2008, 02:16:35 AM
Quote from: 88TurboCoupeman01;229965
Is there anyone who has a chart for these mufflers for the Turbo Coupe.

If you can't see through the muffler...it doesn't belong on a TC.
Title: Muffler flow tests and Exhaust theory
Post by: 86XR7project on February 18, 2009, 09:54:20 AM
Well, I don't want Flowmasters anymore.... Thanks for helping me in my exhaust quest. Hmmm what to buy now?
Title: Muffler flow tests and Exhaust theory
Post by: 88BlueBird on February 18, 2009, 12:11:20 PM
I have that exact set of Borla ProXS mufflers used in that test on my car right now.  I bought them for Anderson years ago. I'm quite happy with them. They are loud at WOT, but don't drone when cruising down the highway.
Title: Muffler flow tests and Exhaust theory
Post by: V8Demon on March 29, 2009, 11:55:01 AM
An excellent question was asked in another thread.

Quote from: Grumbles;264511
Will an H (or X) pipe installed AFTER the cats be as effective as one installed beforehand?
EDIT: Sorry thread hijack.


Here's a quote from a write-up I linked to above concerning that particular case:

Quote
If, to stay legal your exhaust system must run catalytic converters, then the possibility of loosing power goes up dramatically, but it certainly does not mean the game is lost. The first rule of thumb here is if the cats must be in the original position, use the highest-flow components that can be physically installed. For high-flow, high-performance cats, one of the first places I would try would be Random Technologies. Some of this company's key employees drag race late model-street legal machines and are serious about performance. Also in the business of marketing genuine hi-flow cats and cat systems are Walker (Dynomax), Magnaflow, Dynatech and, for a number of specialized truck installations, Gale Banks. These are not the only ones, but they are all the companies of which I have experienced the no-nonsense functionality of their products.If the position of the cats can be moved to such an extent that the length going into the cats represent the secondary tuned length, then we find that to an extent, the cat, if large enough, can, in part, act as a resonator box. Moving the cats to a more favorable position then is rule number 2 when cats must be used.Rule number 3 is that if there is room to put a crossover or an X-pipe before the cats, then that's almost always the best place. Anything after the cats will drop the sound level but is unlikely to increase power unless the flow of the mufflers you chose was significantly short of what was needed.
Title: Muffler flow tests and Exhaust theory
Post by: Cougar5.0 on March 29, 2009, 12:35:38 PM
OK, I got rid of the 18" Magnaflows (anybody want them?) and switched to Corsa "Drone Buster" Mufflers (http://"http://www.corsaperf.com/CorsaDbMufflerSeries.aspx"). I must sadly report that they didn't reduce drone on my full 2 1/2" system using an off-road H-pipe.

Part of the plan was to weld Catco's into the H-pipe to reduce odor and perhaps lower overall noise levels to some extent. I have a set of the Magnaflow high-cell density cats that can fit almost anywhere (only 4" diameter and 11" long) - I am now wondering if I could incorporate them into my flow tubes that go between the H-pipe & mufflers.

Hmmmmmm....
Title: Muffler flow tests and Exhaust theory
Post by: Scott D on July 25, 2010, 06:22:08 PM
Quote from: Cougar5.0;214549
Here's my favorite muffler shootout article - just the all-important comparison tables ;)

(http://i43.photobucket.com/albums/e360/Domeskull/mufflercomparesht1.jpg)
(http://i43.photobucket.com/albums/e360/Domeskull/mufflercomparesht2.jpg)


Those charts are all well and good, but how often are cars driven around the street, cruising at 5,500-6,700?
Title: Muffler flow tests and Exhaust theory
Post by: Masejoer on July 25, 2010, 08:19:09 PM
Quote from: 88BlueBird;257477
They are loud at WOT, but don't drone when cruising down the highway.

Just do you guys know, mine drone...I picked them up based on comments like the above.

1800rpm's and it sounds like I've got a subwoofer vibrating at whatever frequency it is (hard to estimate). If you see this, what does the underside of your car look like? Drone is an issue of resonant frequencies and the fact that both pipes being the same length will act like a tuning fork.

The mufflers sound healthy enough from the outside, flow well, and should last just about forever.