I yanked this off the ls1tech website because it seemed very informative and thought I would share...I had no added value to this information, it was just a copy and paste.

True Dual Muffler flow and dB comparison, Hooker Maxflow & Bassani Real Street?

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The results in HP order:
1.Flowtech Warlock (open) 374.2 hp/ 333.1 tq
2.Bassani Real Street 373.7 hp/ 333.8 tq
3.Hooker Maxflow 373.5 hp/ 333 tq
4.Borla XS 373.3 hp/ 332.6 tq
5.Magnaflow 372.8 / 332.5 tq
6.MAC 372.3 hp / 331.5 tq
7.Flowtech Afterburner 372.3 hp/ 330.1 tq
8.Hooker Aerochamber 372.1 hp/ 330.4 tq
9.Bassani 372 hp/ 333.5 tq
10.Spintech 371.6 hp/ 332.2 tq
11.Edelbrock Performer RPM 370.9 hp / 331.3 tq
12.Borla XR1 370 hp/ 334 tq
13.Flowtech Terminator 369.5 hp / 331.3 tq
14.Dynomax Ultra Flo 369.4 / 333.2 tq
15.Flowmaster 369.4 hp / 331.8 tq
16.Flowtech Warlock 366.3 hp / 325.3 tq
17.No muffs 365.2 hp / 330.1 tq

Sound Off in Quietest to Loudest (Decibels):

1.Borla XS, 80db at idle, 90db at 2,000 rpm, 110db at WOT.
2.Hooker Maxflow, 80db at idle, 90db at 2,000 rpm, 120db at WOT.
3.Magnaflow, 82db at idle, 91 at 2,000 rpm, 114db at WOT.
4.Flowmaster, 82db at idle, 93 at 2,000 rpm, 115db at WOT.
5.Flowtech Warlock, 83db at idle, 92 at 2,000 rpm, 112db at WOT.
6.Dynomax UltraFlo, 83db at idle, 94 at 2,000 rpm, 113db at WOT.
7.Borla XR1, 83db at idle, 96db at 2,000 rpm, 118db at WOT.
8.Bassani Street, 83db at idle, 96db at 2,000 rpm, 120db at WOT.
9.Edelbrock RPM, 84db at idle, 93db at 2,000 rpm, 118db at WOT.
10.Bassani Real Street, 84db at idle, 96db at 2,000 rpm, MAX. (120+db).
11.Flowtech Afterburner, 86db at idle, 94db at 2,000 rpm, 115db at WOT.
12.Flowtech Terminator, 86db at idle, 94db at 2,000 rpm, 119db at WOT.
13.Hooker Aerochamber, 87db at idle, 94db at 2,000 rpm, 114db at WOT.
14.SpinTech, 87db at idle, 97db at 2,000 rpm, 116db at WOT.
15.MAC, 87db at idle, 98db at 2,000 rpm, 119db at WOT.
16.No Muffler, 91db at idle, 103db at 2,000 rpm, MAX. (120+db).

 

Hmm...interesting. I've never heard of Bassani mufflers. Good information.

 

For those planning on making the World Tuning For Beer Tour in Michigan this August :

I'm planning on being there and if anyone is interested I can bring a dB meter so you can get "unofficial" numbers for your car.

 

Interesting. Those numbers can be very hard to find. Know where they came from?

I'm not surprised by the Magnaflow, Borla, or Bassani, but I am by the Hooker Max Flow. Based on their poor reputation in the sidepipe muffler arena, I assumed their cans were probably crap, too. Guess not! Dynomax Ultra Flo placed lower on flow than I expected.

 

how come 'no muffler' is the worst flow and the quitest of all...??

 

What type of bends in the exhaust? How big is the exhaust pipe? What, if any, tailpipes after these mufflers? All of these will drastically affect flow so these answers need to be known before any conclusions can be made.

 

Good question. Hmmmmm........

 

True, but as long all of them were tested using the same stuff fore and aft, it shouldn't matter. The actual number is irrelevent in this case, it's the diffence between them that's important.

Like I said, where did they get these numbers? Is is just a scavenged list from all over the 'net? If so, these numbers are worthless. Are they manuafacturers claims? If so, they are worthless. Did they actually buy samples of each of these and spend the time on a dyno to test each one with a full tune between? You get the idea...

 

Re-read the numbers. The open pipes are by far the loudest (more than the decibel meter could measure at WOT. The torque numbers are pretty flat across the chart. I would expect that. HP numbers vary a bit more and it's not unusual for a muffler to improve scavenging and HP when compared to a straight pipe on factory manifolds.

We need to know the test bed.

 

and not a single one of those will fit our cars

 

Here is where i picked up this info:

http://www.ls1tech.com/forums/showthread.php?p=890071

 

? why not, almost any muffler can be made to fit ???

 

OK, so what "article"? Hot Rod? Car Craft? Some internet mag?

 

yeah but I'm tired of fabricating

 

can we get a test done on the Corz special sidepipe?

 

what i know for sure is that on my 406ci 570hp engine i have tested different mufflers on my hooker side pipes and the car get flat dead after 5.000 rpm if i add stuff to quiet it and feels pretty spirited fm 4.000 rpm to 6.000 if i go open exaust...i never thought the flow was that important to an engine, i might loose over 50 hp if only add a 3'' chambered muffler to the 4'' side pipe! and over 5.000 rpm they could be double or more...

 

Sure, but you are running on the ragged edge with all the best parts availabe, I'd wager. Tuned, long tube headers, I'm sure. Your headers are doing the scavenging, so anything after the collector is fighting that. Plenty of people out running serious engines see results like you. Secondary pipe length is often tuned to a certain length, as well. Something the 15" long range seems to be common. The 427 my family raced used to run with open collectors because even the 40" of open 4" side tube hurt the top end. They (Dad and Dan) never went to so far as to tune a length, but some guys do.




I'm not arguing that your results aren't valid. I'm sure they are. I'm just saying the results of this published "test" aren't unrealistic, but also can't be totally trusted until we can determine how the numbers were attained.