Learned something new

[91Bear]

When I took the truck to get new exhaust pipes, I went ahead and got dual exhausts. The guy asked me if I wanted Flowmasters.

"Sure, whatever," I said.

Flowmasters = glass packs.

Hmmm...It LOOKS like my grandpa's truck but it sure doesn't SOUND like grandpa's truck.

Oooops.

[AK F100]

Cool, Now ya just got to post a sound clip.

[flyboy2610]

Cool, Now ya just got to post a sound clip.

I'm thinking he didn't "oops" in a positive fashion from his viewpoint.

[AK F100]

Cool, Now ya just got to post a sound clip.

I'm thinking he didn't "oops" in a positive fashion from his viewpoint.

Gotcha, I did not catch that at first , but I figured it out just as I hit "Submit".

That's a bummer if it does not sound like you wanted. It's very interesting how big a part the sound makes, I know finding the sound I want is just about as important as how good it runs.

[ToughOldFord]

I thought Flowmasters are a turbo muffler?

[91Bear]

Whatever they are, they are loud.

Grandpa never had much use for any of that. I can hear him now, "G#$ D@*# yardbirds makin' all that noise!"

[BobbyFord]

A guy at 460ford.com that owns a dyno did a muffler test a few years back. He tested several different muffler brands on the same engine. His findings were that Flowmaster mufflers actually caused a decrease in horsepower. The two best mufflers that he tested were Dynomax and Magnaflow (both of which I think sound better anyway).

[91Bear]

Had you done your homework and shopped around for the Flowmaster series with a sound that you like, you would have enjoyed your Flowmaster purchase a lot more.

Yeah, probably so, but I am pretty new at muffler buying - actually very new. Never had to buy any before.

As an old-timer I once knew used to say, "Live and learn. Die and forget it all." (Rest in peace, J.G.!)

[mrtleavitt]

I don't know about decreasing horsepower. Sure maybe that was the case on his and maybe it flowed wrong or something. I have a buddy that said he got more horsepower out of stock FE 390 exhaust manifolds from a truck than he did with heddman hedders. So take info for what it's worth.

[bntyhntr00]

A guy at 460ford.com that owns a dyno did a muffler test a few years back. He tested several different muffler brands on the same engine. His findings were that Flowmaster mufflers actually caused a decrease in horsepower. The two best mufflers that he tested were Dynomax and Magnaflow (both of which I think sound better anyway).

A lot of it depends on the model of Flowmaster tested for most street driven vehicles flowmasters are over the top because of the lack of restriction but in racing circuits that require mufflers flowmasters are the domnant choice. Flowmaster started out as a muffler for race vehicles and then just used their credibility in that arena (and peoples desire to sound like a race car) as a marketing tool. It worked quite well for a long time until the Magnaflow's and the Dynomax's. Even so, for most vehicles the horsepower gained by scrapping the Flowmasters is a number that were you to swap them without somebodies knowledge they wouldn't even know. just my

[BobbyFord]

A guy at 460ford.com that owns a dyno did a muffler test a few years back. He tested several different muffler brands on the same engine. His findings were that Flowmaster mufflers actually caused a decrease in horsepower. The two best mufflers that he tested were Dynomax and Magnaflow (both of which I think sound better anyway).

A lot of it depends on the model of Flowmaster tested for most street driven vehicles flowmasters are over the top because of the lack of restriction but in racing circuits that require mufflers flowmasters are the domnant choice. Flowmaster started out as a muffler for race vehicles and then just used their credibility in that arena (and peoples desire to sound like a race car) as a marketing tool. It worked quite well for a long time until the Magnaflow's and the Dynomax's. Even so, for most vehicles the horsepower gained by scrapping the Flowmasters is a number that were you to swap them without somebodies knowledge they wouldn't even know. just my

The guy that did the muffler test builds race motors for boats and cars, he also races himself. None of the set-ups he tested were on a street motor. Not many of the guys over on 460ford.com use Flowmasters. According to the engine builders the Flowmasters do not flow enough and are too restrictive.

Here's a few exhaust threads:

http://www.460ford.com/forum/showthread ... t+mufflers

http://www.460ford.com/forum/showthread ... t+mufflers

http://www.460ford.com/forum/showthread ... t+mufflers

Finally, here is something from a CarCraft Magazine article about best bang for your buck on mufflers. Flowmasters didn't even make the HP list:

I have listed here a muffler shootout test done by CAR CRAFT, they show the best bang for the buck, and show the db's

The Mufflers
MAKE MODEL Part No. COST
SUMMIT Turbo 630125 $14.75
THRUSH Magnum Glasspack 24214 $16.50
THRUSH Boss Turbo 17718 $23.95
HOOKER Competition 21006 $25.95
DYNOMAX Super Turbo 17733 $28.50
DYNOMAX Race Magnum 24215 $31.95
HOOKER Super Competition 21106 $35.95
SUMMIT Fully Welded 630325 $38.69
FLOWTECH Afterburner 50322 $39.95

MUFFLER FLOW TEST

MUFFLER Flow at 28-in H20
DynoMax Race Magnum 528.64 cfm
Thrush Magnum Glasspack 507.40 cfm
Summit Fully Welded 343.38 cfm
Flowtech Afterburner 342.20 cfm
DynoMax Super Turbo 333.94 cfm
Hooker Competition 232.46 cfm
Hooker Super Competition 320.96 cfm
Summit Turbo 331.16 cfm
Thrush Boss Turbo 297.36 cfm

MUFFLER Idle dB WOT dB
DynoMax Super Turbo 89 123
DynoMax Race Magnum 94 133
Flowtech Afterburner 92 124
Hooker Competion 92 122
Hooker Super Competion 90 125
Summit Turbo 89 124
Summit Fully Welded 92 125
Thrush Boss Turbo 90 123
Thrush Magnum Glasspack 92 128

DYNO TEST
All mufflers were dyno-tested on a 355-cube SBC with 10.0:1 compression, Air Flow Research 190 aluminum heads, a CompCams 292 hyd. a Victor Jr. intake, a Holley 750-cfm double-pumper, and 1 5/8 Headman headers.


MUFFLER HP TORQUE 2,500-6,000rpmAverage
Hooker Competition 397.4 381.1 286.8hp/351.9 lb-ft
Thrush Boss Turbo 407.1 384.9 292.1 hp/357.5 lb-ft
DynoMax Race Magnum 409.5 394.3 298.8 hp/366.9 lb-ft
Flowtech Afterburner 409.7 391.2 294.8 hp/361.7 lb-ft
Thrush Glasspack 409.5 389.8 297.7 hp/365.3 lb-ft
Summit Turbo 411.5 386.3 291.5 hp/357.4 lb-ft
DynoMax Super Turbo 412.7 387.2 292.6 hp/358.6 lb-ft
Hooker Super Comp 413.8 387.2 292.8 hp/359.0 lb-ft
Summit Fully Welded 415.4 390.7 295.6 hp/362.4 lb-ft


more numbers for ya'll who like numbers.

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

[Sam I Am]

Flowmaster makes a very wide variety of mufflers. Just because the one muffler that one guy tried flowed less with that specific application doesn't mean all Flowmasters suck. They even have a muffler series designed specifically for big blocks with large displacement. If he used a daily driver small block sized muffler on a race prepped 460 he should expect a lack of performance, that's just common sense. An exhaust system will only flow as much as the smallest restriction will allow.

I also noticed that your Car Craft quote didn't include which series Flowmaster they used for their small block Chevy. Different series mufflers have different flow characteristics and comparing one to another is just like comparing apples vs oranges.

Check out the site link above to see the wide variety of products Flowmaster makes and sells. I don't expect you to buy some, but then I don't expect one guy's opinion to put Flowmaster out of business either.

[BobbyFord]

I'm not trying to "put Flowmaster out of business", I'm simply trying to provide useful information. I did not write the CarCraft article but I did notice that there is not a single Flowmaster muffler listed in the top 9 best mufflers for your money, regardless of model or part number. A lot of guys here are on a budget and cannot afford to use the best race mufflers available. Flowmaster 40 series through 80 series mufflers are all multi-chambered style mufflers, NO multi-chambered muffler made flows better than a straight-through design.
The guy that ported my heads took third place in the Popular Hot Rodding Engine Masters Competition, he does not recommend any Flowmaster or any multi-chamber design muffler in a performance application; that's good enough for me. Just my opinion.

[Chaseman]

weird , what kind of exhuast shop is that? Who uses the term flowmasters for glass-packs? I didn't even know they made glasspacks.

[sport71]

I think that glass packs are too loud, and of course they have the straight flow. Even though I deadend the whole truck, those mufflers are still loud . I'd hate to make a trip with all that ruckes . I got the 50 series 3" Flowmaster mufflers, because of the less sound. I know that my 390 will still kick some butt , and not so loud. If I need the extra 5 HP I'll get the cut outs.