American Rumble
Aftermarket muffler sound great, but is one better than the others? We test the power and the fury of 15 mufflers
Text by Steve Turner
Photos courtesy of
Anderson Ford Motorsport
He can't leap over tall stacks of mufflers, but Rick Anderson might just be a dyne superman. With customer Jason Moore’s help, Rick managed to dyno 15 pairs of mufflers in one day. Of course, he did have a little trick up his sleeve in the form of some custom side-exit pipes fromBassani. These NASCARstyle pipes allowed Rick to swap out mufflers with the car still strapped to his in-ground chassis dyne. Since he ran them without tailpipes, these mufflers would likely make a bit more torque and a bit less horsepower in a full street application, but each one was tested the same way and a-b comparisons were all we sought.
Horse Sense: According to Webster's Unabridged Dictionary. a decibel is “a unit used to express the intensity of a sound wave, equal to 20 times the common logarithm of the ratio of the pressure produced by the sound wave to a reference pressure, usually .0002 microbar.” Uh, on second thought, just think of it as the horsepower of sound.
After a K&N air filter, an after- cat exhaust system is likely the second modification a Mustang owner adds to his new ride. Let's face it—the factory exhaust system just doesn't do justice to the power that's under the hood. The only way to announce you're a real player on the street is with a set of large-diameter tailpipes and throaty mufflers. But the big decision is which muffler to buy for your Mustang. Well fortunately your friends at 5.0&SF are always looking out for you. And we were a bit curious to see how today modern mufflers stack up against one another (we have Mustangs too...).
The trick in the magazine world is balancing the time needed for such comprehensive testing, the location of a suitable test car, and the borrowing of a chassis dyno for the time required. Fortunately for us, we long ago developed a trusting friendship with Rick Anderson at Anderson Ford Motorsport in Clinton, Illinois.
In addition to running MM, Rick simply loves to dyno parts. He enjoys finding out what parts work on certain combos so he knows what to sell you when the phone rings. Likewise, it helps him decide what parts to stock, and it occasionally gives him ideas for developing new parts. The bottom line is, we know Rick gives us the straight scoop, and he doesn't even mind giving up some of his free time to give it to us.
After Rick agreed to test a few mufflers for us (we always add to his list, and he always seems to agree without complaint), he had to track down a suitable test 'Stang.
Would you let us run your '90 5.0 on the dyno 66 times for a magazine story? Jason Moore did. His coupe sports a 306 with D.S.S. pistons and main support, AFM Stage Twisted Wedge heads, an AFM N-91 camshaft, an AFM Stage lll Trick Flow Track Heat intake, a 75mm throttle body, an MM Power Pipe, a Pro-M 80mm mass air, 4.56 gears, and a Programmable Management System. His car revved up to 6,750 rpm 66 times and made more than 370 hp on nearly every pull. That's consistent.
First on the block in our alphabetic list of test subjects wore two offerings from Bassani—the company's Quiet Thunder street muffler and its racy Real Street muffler. The standard QT muffler cranked off solid peak numbers of 372 hp at 6,250 rpm and 333.5 lb-ft of torque at 5,500. As you would expect the Real Street mufflers took over where the QT mufflers left off, registering peaks of 373.7 hp at 6,250 and 333.8 lb-ft of torque at 5,500. Just comparing those two mufflers, the RS is a hall-pound lighter than the 11-pound QT muffler. Their sound levels are dead-on until wide-open throttle, where the RS becomes really loud. Finally, continuing Bassani's tradition of quality, while both mufflers feature full stainless-steel construction, they both also pack the highest price in our test ($186 each).
Several companies sent two or more muffler designs for our test, and Borla's value- minded XS piece offered the first surprise. Boasting full stainless construction and weighing only 71/2pounds, the XS actually outperformed its racy big brother, the XR1, and did so while delivering some of the lowest sound output in our test (see the Sounding Off sidebar). All told, the $129.99 (each) XS mufflers cranked out peaks of 373.3 hp at 6,250 and 332.6 lb-ft of torque at 5,500.
Though we already hinted the XS did a bit better, the Soda XR1 was certainly no slouch. This full-stainless racing muffler was just a tick quieter than Bassani's race offering, and it delivered peaks of 370 hp at 6,000 rpm and 334 lb-ft of torque at 5,500. Unfortunately, its louder, straight- through design didn't deliver additional horsepower on our combination for the $38 premium it commands over the XS muffler, but perhaps that dynamic changes on a more powerful combo.
DynoMax's offering should be familiar to most of you as the Race Magnum. These days it runs under the Ultra Flo Welded moniker, but it's the same muffler. Despite its aluminized construction, the UFW muffler features a midrange price of $80 each and offers relatively quiet output with a flyweight of 6 pounds. When the rubber met the rollers, the UFW delivered a slightly off-pace horsepower peak of 369.4 ponies at 6,250 rpm, but the torque hung in with the top performers at 333.2 lb-ft at 5,500.
Having been around these parts for years, we've become partial to the sound of a few of those mufflers. Among that group is Edelbrock's Performer RPM muffler, which offers stainless-steel construction For the second-highest price point in our test-$178.78 each-The Edolbrock piece weighed in at 103/2pounds and delivered comparable sound numbers at idle and 2,000 rpm, but it became loud at WOT, which isn't a real surprise as this is Edelbrook's racier piece. On the dyno, it offered respectable peaks of 370.9 hp at 6,250 rpm and 331.3 lb-ft of torque at 5,500.
Though we went out of our way to request mufflers identical to those found in most companies' Mustang after-cat systems, we did get a strange submission from Flowmaster. This muffler was designed for SUV applications, but with deadlines bearing down, we couldn't really have a muffler test without the storied Flowmaster. This hefty 16-pound muffler was actually fairly quiet down low and opened up at WOT As far as the power numbers, it hung right in with the pack, registering peaks of 369.4 at 6,000 rpm and 331.8 lb-ft of torque at 5,500. Surprising given its mild-steel construction, the muffler we ran sells for $135 each, but we've seen Mustang-spec Flow- masters selling for half that on the mail- order market.
The factory exhaust system just doesn't do justice to the power that's under the hood
Want the performance bargain of the bunch? Check out Flowtech's Afterburner muffler Weighing in at only 9 pounds, the Afterburner is a bit loud down low, but it's average at WOT However, at only $42.81 each, the Afterburner's peaks of 372.3 hp at 6,250 rpm and 330.1 lb-ft of torque at 5,500 were certainly impressive. Of course, with that price you are buying a less-durable aluminized muffler, but if you live in a climate without salty roads, this muffler is a steal.
Weighing 31/2pounds heavier than its likewise-aluminized Afterburner cousin, the Flowtech Terminator is a little louder at WOT and a bit more expensive at $58.78 each. So you'd have to think it is worth a bit more power, right? Actually the power was down a hair and the torque up just a bit with peaks of 396.5 hp at 6,250 rpm and 331.3 lb-ft at 5,500. The Terminator did offer the next-lowest price point compared to the Afterburner.
Better yet all the
Mufflers handily out-performed
an open exhaust
The most unique offering in our test was Flowtech's Warlock muffler, which is designed to run closed on the street and to be opened up at the track or dyno. Stepping up to $74.93 each nets you the aforementioned removable cutout and mild-steel construction, which adds up to a 151/2 pound muffler. Naturally, we had to dyno this one twice. In closed/street form, the Warlock produced the lowest peaks in our test-366 hp at 6,250 rpm and 325.3 lb-ft of torque at 5,500. In closed form, it was actually relatively quiet, but opening it up via the cutout pegged our dB meter at WOT. Naturally, this helped the power output too. The open Warlock jumped to the head of the class with peaks of 374.2 hp at 6,250 rpm and 333.1 lb-ft of torque at 5,750.
Best known for its line of headers, Hooker is also in the muffler biz these days. The company sent us a pair of its offerings to test. First up was the Aerochamber, which combines a stainless steel core with an aluminized case and weighs a considerable 141/2 pounds. Despite the upgrade of a stainless core, the Aerochamber is still one of the more affordable mufflers we tested at $68.82 each, and it was in the middle of the pack with its sound output. It turned in solid peaks of 372.1 hp at 6,250 rpm and 330.4 lb-ft at 5,500.
For the same price as the Aerochamber, you can opt for Hooker's MAX flow muffler.This piece weighs a bit less than its cousin at 121/2, pounds, and it's actually a bit quieter at low rpm before really rumbling at high rpm. Once it hit the rollers, the MAX flow showed off as another bargain with impressive peaks of 373.5 hp at 6,250 rpm and 333 lb-ft of torque at 5,500 rpm. The MAXflow also offers a stainless steel core housed in an aluminized case.
Long known in the market as offering value-priced performance parts, MAC Products sent us its upmarket stainless steel Flowpath muffler for our test. Despite the more expensive material, the stainless units cost only $79.50 and are on the lighter end of our range at 101/2 pounds. Short of the racy mufflers in our test, the Flowpaths were some of the louder mufflers we tested throughout the rpm range. On the dyno they produced solid peaks of 372.3 hp at 6,250 rpm and 331.5 lb-ft of torque at 5,500.
He wanted to use a naturally aspirated car to ensure the repeatability of a test certain to be dealing with a handful of horsepower difference. Naively volunteering was AFM customer Jason Moore, whose '90 coupe kicks out 370 hp to the rear wheels and packs high-11-second potential. It was the perfect car to push our mufflers beyond what your street 'Stang is likely to run. Jason not only allowed us to make 66 dyno pulls with his car to ensure repeatability, but he also stuck around from 9:30 a.m. to 8:00 p.m. to help Rick with tile test. Thanks, Jason!
|
|
Open Exhaust
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Bassani
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Bassani Real Street
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Borla XS
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Borla XR1
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DynoMax Ultra Flo
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Edelbrock Performer RPM
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|||||||
|
RPM
|
PWR
|
TRQ
|
PWR
|
TRQ
|
PWR
|
TRQ
|
PWR
|
TRQ
|
PWR
|
TRQ
|
PWR
|
TRQ
|
PWR
|
TRQ
|
|
2,750
|
103
|
196.7
|
87.1
|
182.9
|
89.9
|
188.8
|
111.7
|
213.4
|
102.1
|
195
|
105.1
|
200.7
|
105.3
|
2012
|
|
3,000
|
138.9
|
243.1
|
109.1
|
208.4
|
107.2
|
204.7
|
148.3
|
259.6
|
141.1
|
247
|
140.9
|
246.7
|
143.9
|
251.9
|
|
3,250
|
168.6
|
272.4
|
148.2
|
255.9
|
148.6
|
260.2
|
176.6
|
285.4
|
168.9
|
273
|
168.4
|
272.2
|
170.6
|
275.7
|
|
3,500
|
189.6
|
284.5
|
1732
|
279.8
|
177.1
|
286.2
|
195.4
|
293.2
|
189.1
|
283.7
|
189.3
|
284.1
|
1902
|
285.5
|
|
3,750
|
202.3
|
283.3
|
192.3
|
288.5
|
194.8
|
292.3
|
207.9
|
291.1
|
203.7
|
285.3
|
204.5
|
286.4
|
203
|
284.4
|
|
4,000
|
214.6
|
281.8
|
204.8
|
286.8
|
208.3
|
291.8
|
219.2
|
287.8
|
215.6
|
283.1
|
214.9
|
282.2
|
215.1
|
222.4
|
|
4,250
|
239.6
|
296.1
|
216.6
|
284.3
|
220.7
|
289.8
|
244.3
|
301.9
|
243.2
|
300.5
|
243.1
|
300.4
|
242.6
|
299.8
|
|
4,500
|
268.5
|
314.5
|
241.3
|
2982
|
244.7
|
302.4
|
274.1
|
319.9
|
270.9
|
316.2
|
271.9
|
317.3
|
272.2
|
317.7
|
|
4,750
|
291.6
|
322.4
|
272.3
|
317.8
|
274.1
|
319.9
|
294.6
|
325.7
|
295
|
326.2
|
295
|
326.1
|
294.6
|
325.7
|
|
5,000
|
308.7
|
324.2
|
293.7
|
324.7
|
295.6
|
326.8
|
310.1
|
325.7
|
311.7
|
327.4
|
310.9
|
326.5
|
310.3
|
326
|
|
5,250
|
326.3
|
326.4
|
308.7
|
324.3
|
310.9
|
326.6
|
329.4
|
329.6
|
330
|
330.2
|
3292
|
329.3
|
328.2
|
328.4
|
|
5,500
|
345.7
|
330.1
|
329
|
329.1
|
330.8
|
330.9
|
348.3
|
332.8
|
349.8
|
334
|
349
|
333.2
|
347
|
331.3
|
|
5,750
|
359.2
|
328.1
|
349.3
|
333.5
|
349.6
|
3332
|
363.8
|
332.3
|
362.4
|
331
|
362.8
|
331.4
|
362.2
|
330.9
|
|
6,000
|
365
|
319.5
|
361.4
|
330.1
|
364.1
|
332.6
|
370.9
|
324.6
|
370
|
323.9
|
368.7
|
322.8
|
368.7
|
322.7
|
|
6,250
|
385.2
|
306.9
|
369.3
|
323.3
|
3712
|
324.9
|
373.3
|
313.7
|
369.6
|
310.6
|
389.4
|
310.4
|
370.9
|
311.7
|
|
6,500
|
358.8
|
289.9
|
372
|
312.6
|
373.7
|
314.1
|
369.2
|
298.4
|
369.8
|
298.8
|
367.4
|
296.9
|
366.1
|
295.8
|
|
|
Flowmaster
|
Flowtech Afterburner
|
Flowtech Terminator
|
Flowtech Warlock
|
Flowtech warlock(open)
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Hooker Aerochamber
|
Hooker MAXflow
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|||||||
|
RPM
|
PWR
|
TRQ
|
PWR
|
TRQ
|
PWR
|
TRQ
|
PWR
|
TRQ
|
PWR
|
TRQ
|
PWR
|
TRQ
|
PWR
|
TRQ
|
|
2,750
|
102.8
|
1962
|
103.9
|
198.4
|
102
|
194.8
|
102.6
|
195.9
|
109.5
|
209.1
|
103.4
|
197.4
|
102.1
|
196
|
|
3,000
|
140
|
245.1
|
140.9
|
246.7
|
138.9
|
243.2
|
142
|
248.6
|
151.5
|
265.1
|
140.5
|
246
|
142
|
248.6
|
|
3,250
|
168.9
|
273
|
168.4
|
272.2
|
170.3
|
275.1
|
169.4
|
273.7
|
178.9
|
289.1
|
168.3
|
272
|
172.5
|
278.8
|
|
3,500
|
189.4
|
284.1
|
189.8
|
284.9
|
189.1
|
283.8
|
185.6
|
278.5
|
193.3
|
290.1
|
190.7
|
288.2
|
189
|
283.6
|
|
3,750
|
202.8
|
284
|
202.9
|
284.1
|
202.4
|
283.4
|
199.7
|
279.7
|
207.1
|
290
|
203.2
|
284.7
|
204
|
285.7
|
|
4,000
|
213.2
|
279.9
|
212.9
|
279.5
|
213.2
|
279.9
|
211.6
|
277.8
|
220.8
|
290
|
213.6
|
280.4
|
214.7
|
282
|
|
4,250
|
242.2
|
299.3
|
240.5
|
297.2
|
241.6
|
298.6
|
237.8
|
293.9
|
248.1
|
306.6
|
240.2
|
296.9
|
244.8
|
302.6
|
|
4,500
|
271.7
|
317.1
|
270
|
315.1
|
270.7
|
316
|
264.4
|
363.6
|
276.9
|
3232
|
270.6
|
315.9
|
274.8
|
320.8
|
|
4,750
|
291.2
|
322
|
292.7
|
323.6
|
294.1
|
325.2
|
281.9
|
311.8
|
292.9
|
323.9
|
293.5
|
324.5
|
296.1
|
327.4
|
|
5,000
|
306.6
|
322
|
306.8
|
322.3
|
307.4
|
322.9
|
295.7
|
310.6
|
306.2
|
321.7
|
308.3
|
323.9
|
309.9
|
325.5
|
|
5,250
|
327.6
|
327.7
|
326.9
|
326
|
326.8
|
327
|
318.3
|
318.4
|
328.6
|
328.7
|
327.1
|
327.3
|
329
|
320.2
|
|
5,500
|
347.4
|
331.8
|
345.7
|
330.1
|
346.9
|
331.3
|
340.7
|
325.3
|
348.8
|
333.1
|
346
|
330.4
|
348.7
|
333
|
|
5,750
|
361
|
329.7
|
359.7
|
328.6
|
361.3
|
330
|
358
|
3252
|
3623
|
331
|
360.4
|
329.2
|
362.7
|
331.3
|
|
6,000
|
389.4
|
323.3
|
3684
|
322.6
|
368.4
|
322.5
|
363.1
|
317.8
|
370.7
|
324.5
|
368.8
|
322.9
|
370.3
|
324.2
|
|
6,250
|
368.3
|
309.5
|
372.3
|
312.9
|
389.5
|
310.5
|
388.3
|
307.8
|
374.2
|
314.4
|
372.1
|
312.7
|
373.5
|
313.6
|
|
6,500
|
363.7
|
293.9
|
366.3
|
296
|
366.2
|
295.9
|
363.7
|
293.9
|
369.7
|
298.8
|
368.8
|
298
|
371.8
|
300.4
|
|
|
MAC
|
MagnaFlow
|
SpinTech
|
|||
|
RPM
|
PWR
|
TRQ
|
PWR
|
TRQ
|
PWR
|
TRQ
|
|
2,750
|
104.6
|
199.8
|
105.3
|
201.2
|
105.2
|
201
|
|
3,000
|
142.3
|
249.1
|
143.8
|
251.8
|
142.2
|
249
|
|
3,250
|
166.3
|
268.7
|
171.3
|
276.8
|
167.3
|
270.3
|
|
3,500
|
188.6
|
283
|
189.4
|
284.3
|
190
|
285.1
|
|
3,750
|
202.9
|
284.2
|
204.3
|
286.1
|
203.6
|
285.1
|
|
4,000
|
213.1
|
279.9
|
215.8
|
283.4
|
213.3
|
280
|
|
4,250
|
240.2
|
296.8
|
244.5
|
302.1
|
240.7
|
297.5
|
|
4,500
|
269.5
|
313.4
|
274.2
|
320.1
|
269.5
|
314.6
|
|
4,750
|
292.7
|
323.6
|
294.1
|
325.2
|
293
|
324
|
|
5,000
|
310.3
|
325.9
|
308.8
|
324.4
|
310.8
|
326.5
|
|
5,250
|
3282
|
328.4
|
328.9
|
329
|
329
|
329.1
|
|
5,500
|
347.1
|
331.5
|
348.2
|
332.5
|
347.9
|
332.2
|
|
5,750
|
362.7
|
331.3
|
363.6
|
332.1
|
362.2
|
330.8
|
|
6,000
|
368.7
|
322.7
|
370.6
|
324.4
|
369.6
|
323.5
|
|
6,250
|
372.3
|
312.9
|
372.8
|
3132
|
371.6
|
312.3
|
|
6,500
|
363
|
293.3
|
369.1
|
298.3
|
369.5
|
298.6
|
There's so much data here, we simply don't have room to dissect it all, but you have it now, so you can choose the mufflers you are interested in and run the numbers through Excel if you are really serious about eking out every last horsepower. If so, Rick Anderson says to pay particular attention to the average horsepower between 4,700 and 6,600 rpm.This range is critical for drag rating this combo. Rick says the best muffler in that range is the Bassani Real Street, but it's probably too loud for the street (and that's saying something coming from Rick).The Hooker MAXflow, both Sodas, and the MagneFlow closely followed the Bassani RS with good average horsepower In that range. In the end, we say find one that sounds good to you and your wallet and go have fun.
So, what did all this testing uncover? It turns out today's mufflers are all good. If you want to squeeze out every last drop of power, there are a few standouts, so check the captions and dyno sheets for the details. But all the mufflers are so close you really can’t go wrong. Just find a pair that sounds good to you and bolt’em on. Better yet, all the mufflers handily outperformed an open exhaust, so you can tell that annoying guy in the neighborhood with the jacked-up Nova to put on some mufflers and he'll actually be faster. 5.0
Along with the Bassani and Edelbrock units, one of our subjective favorites from a tonal perspective is the MagnaFlow. This stainless stool part weighs only 104 pounds and costs just $83.62. So, it's light, cost effective, and fairly quiet too. What's the catch? Apparently there isn't one, as the MagnaFlow yielded good numbers as well, posting peaks of 372.8 at 6,250 rpm and 332.5 lb-ft of torque at 5,750.
With one of the more unique internal structures in our test, SpinTech's aluminized mufflers feature several curled sound traps inside the case. They definitely deliver a unique tone. The mufflers were on the loud side throughout our test range, but they seem to work well. Costing only $79.50 and weighing 11 pounds each, the SpinTechs posted peaks of 371.6 hp at 6,250 rpm and 332.2 lb-ft of torque at 5,500.
Sounding Off
Not only did Jason Moore help dyno test his car 66 times, but he also assisted Rick in logging the decibel outputs of each muffler at idle, 2,000 rpm, and wide-open throttle using a handheld dB meter from Radio Shack. Of course, this was done in the AFM dyne room, which likely made thorn all a bit louder, but all were subject to the same conditions. If you're hunting for the best power from the quietest muffler, it looks as if the Borla XS is your muffler. Most were close at lower rpm, while the loud mufflers stood out at WOT.
|
MUFFLER |
|
|
DECIBELS AT IDLE |
DECIBELS AT 2,000 RPM |
DECIBELS AT WOT |
||
|
No Muffler |
|
91 |
|
103 |
|
Max. |
|
|
Bassani Street |
|
83 |
|
96 |
|
120 |
|
|
Bassani Real Street |
|
84 |
|
96 |
|
Max. |
|
|
Bodo XS |
|
|
80 |
|
90 |
|
110 |
|
Bode XR1 |
|
|
83 |
|
96 |
|
118 |
|
DynoMax Ultra Flo |
|
83 |
|
94 |
|
113 |
|
|
Edelbiock RPM |
|
84 |
|
93 |
|
118 |
|
|
Flowmaster |
|
82 |
|
93 |
|
115 |
|
|
Flowtech Afterburner |
86 |
|
94 |
|
115 |
||
|
Flowtech Terminator |
86 |
|
94 |
|
119 |
||
|
Flowtech Warlock |
|
83 |
|
92 |
|
112 |
|
|
Hooker Aerochamber |
87 |
|
94 |
|
114 |
||
|
Hooker MAXflow |
|
80 |
|
90 |
|
120 |
|
|
MAC |
|
|
87 |
|
98 |
|
119 |
|
Magna Flow |
|
82 |
|
91 |
|
114 |
|
|
SpinTech |
|
|
87 |
|
97 |
|
116 |
SOURCES
ANDERSON FORD MOTORSPORT
Dept. 5.0
P.O. Box 636
Clinton, IL 61727
(217) 935-3106
www.andersonfordmotorsport.com
BASSANI XHAUST
Dept. 5.0
2900 E. La Jolla
Anaheim, CA 92806
(714) 630-1821
www.bassani.com
FLOWMASTER
Dept. 5.0
100 Stony Point Rd., Ste. 125
Santa Rosa, CA 95401
(800) 544-4761
www.flowmastermufflers.com
HOLLEY PERFORMANCEPRODUCTS
Dept. 5.0
(Flowtech and Hooker)
1801 Russellville Rd.
Bowling Green, KY 42101
(270) 781-9741
BORLA PERFORMANCE INDUSTRIES
Dept. 5.0
5901 Edison Dr.
Oxnard, CA 93033
(877) 462-6752
www.borla.com
Mac PRODUCTS
Dept. 5.0
43214 Blackdeer Loop
Temecula, CA 92590-3473
(800)367-4486
www.macperformance.corn
DYNOMAX
Dept. 5.0
2701 N. Dettman Rd.
Jackson, MI 49201
(800) 767-DYNO
www.dynomax.com
EDELBROCK CORP.
Dept. 5.0
2700 California St.
Torrance, CA 90503
(800) 416-8628
www.edelbrock.com
MAGNAFLOW PERFORMANCE EXHAUST
Dept. 5.0
22961 Arroyo Vista
Rancho Santa Margarita, CA 92688
(800)959-9226, ext. 4500
www.magnaflow.com
SPINTECH
Dept. 5.0
4768 Felspar St.
Riverside, CA 92509
(888) 550-7746
www.spintechmufflers.com