I've been reading the sticky about designing a zero loss exhaust. It all sounds good and feasable.

However one of the key factors was muffler flow capacities. The equation used in the article is this:

2.2cfm for every 1hp

So a 500bhp engine would need 1100cfm flow capacity.

On a dual setup you could divide this by two. So all you'd need is 2 mufflers that flow 550cfm, easy isn't it. (For a complete zero loss system there's a bit more to it, but this would be a good start. Try reading the sticky if you want more info).

The biggest problem I have come across is finding flow rates for the different mufflers out there.

So if you have flow data for any mufflers please post it up. Where possible state:

-Make of muffler
-Series or name of muffler
-Length
-inlet/outlet diameter
-and of course flow rate

Failing that any links to other sites with this information will be most helpful.

Many thanks.

 

there was a write up on here a while ago that someone had found that compared about 10 different brands.

 

that sounds good, wonder if anyone can find it. Should maybe made a sticky??

As I did try searching under various criteria, "muffler flow rate", "cfm muffler" and so on.

 

I'm trying to find the same thing out about hi flowing Cats, and debating between 2.5" and 3" tru-duals. This could end up being a very good thread!

 

i dont know the exact numbers but... bullets are the highest, then the flo-pro twister's and spiraltech, then the sweet thunders, and then i believe it goes to the xr1's then the flowmaster one chamber. Those are some of the most popular mufflers... Try going to their sites for actaul numbers...

 

From my understanding, 2.5 TD's should be good for 500bhp and no loss, other components dependant of course.

So this means if your Cats and muffler flow 550cfm or more, you would likely see NO gain from 3" tubing over 2.5" tubing on a 500bhp motor with TD's.

 

I've had a look at a couple of them. So far I've only found one maker who quotes flow rates, and it's not a maker I've heard mention of on here before.

do you have links for any of the manufactures websites. Can't seem to find them all using Google.

Cheers.

 

No way a sweet thunder outflows a XR-1.

 

Muffler Flow Testing

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

************************************************** ***************

This test was performed by 5.0 Mustang & Super Fords Magazine, December 2002 issue (page 55) on a '90 Mustang LX coupe with 370hp and 11 second potential. 66 pulls were made for this comparison:

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).

 

I'm 99% sure that the Dynomax website (www.dynomax.com) has flow numbers for most all of it's mufflers.

 

I wonder how the chambered mufflers flow

 

I think Dynomax/Walker is about the only manufacturer that provides CFM ratings (and even then, not on all of them). It's no coincidence that David Vizard worked with them on some of their designs.