Custom exhaust size.

[Hawt drift chick]

You listen to your buddy O 16581 72452 5 too much, Flowmasters are good mufflers. Just not on turbo cars.

I'll behave this time. ;)

Flowmasters are among the worst flowing mufflers around next to the Thrush Turbo Mufflers. What makes them good for N/A and not turbo cars...? Read around and other than reading it's plain common sense that a baffled muffler or a turbo muffler (the exhaust changes direction) won't flow like something that's basically a straight through pipe. They're good mufflers in the sense of quality, but not in the sense of performance.

I can't find the CFM charts anymore, but flowmasters were in the 300cfms while the dynomax/other straight throughs were in the 800-900cfm area, some flowed the same as a straight through pipe. The trade off for flow though is sound...

[JasonC]

I'll behave this time. ;)

Let's hope :p ;)...

I have been looking around since i seen this thread. And i found some numbers. Must of them have been from Mustang forums. And some full size truck ones. They showed that Flowmaster was on the lower end of the scale for with a couple of different mufflers that flowed worse then the Flowmasters. And yes is common sense that a baffled muffler will flow less then a straight through muffler. And saying that they flow less then stock is just dumb. I did find one site with alot of flow numbers on mufflers but a error will pop up before you can get all of the numbers in and shut down the page :x.

Some of the flow numbers that i've found, I wish they would of done 3" also.
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

[Hawt drift chick]

Yeah, i don't know what stock BMW mufflers flow so i can't say how they compare, i think 0000000000 got mixed up on what i told him some time back about louvered core glasspacks in alot of cases flowing worse than stock. Those numbers seem a little off, Magnaflow 100cfm less than a Borla Turbo is the opposite of what i've seen elsewhere...

I don't know what Magnaflow they tested, but the one in my room is completely straight through.

[JasonC]

Other people was saying the samething on some of the numbers from that test. But like you said who knows what one they used? I couldn't believe the glasspack with louveres test!

[etxxz]

i say, forget about it and run open headers like this guy:

http://youtube.com/watch?v=64RadsqTJyM

^^ i'm doing with a dual 2" setup, droping the car off on friday. pics and music to come.

[082Roy]

dual 2" should sound good and won't be too big, but u should put the muffler at the end and the resonators in the middle to get a better sound...o ya use an X pipe to clean up the rasp before the resonators

Hey Bud,

How would this setup that you've mentioned work without the resonators?
Just the x pipe straight to the muffler?

I've had that setup on the M20 motor, keen know if it would work well with the S50 motor.

Thanks.

[0000000000]

Hey Bud,

How would this setup that you've mentioned work without the resonators?
Just the x pipe straight to the muffler?

I've had that setup on the M20 motor, keen know if it would work well with the S50 motor.

Thanks.

If you read right he mentions an x pipe than resonators than to the muffler, another thing is that this exhaust set up is not for a s50 its for a m50.;)