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Re: Dynomax mufflers VS Flowmasters
[Re: Kern Dog]
#1126505
12/03/11 11:58 AM
12/03/11 11:58 AM
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Joined: Oct 2010
Posts: 183
Eden, Texas
Strawdawg
member
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member
Joined: Oct 2010
Posts: 183
Eden, Texas
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Quote:
There was an interesting post recently about the flow ratings of todays top selling mufflers, with a product from Dynomax testing better than the others. One person posted a spec sheet with the ratings, which was quite helpful, except......HOW do you translate flow ratings into a gain/loss comparison in terms of horsepower? I understand that the Dynomax had a far higher rating, somewhere near 99% with the trusty Flowmaster being in the sub 50% range. I'm curious since I have Flowmaster 42451 mufflers in the Charger and have been pleased with the sound, but if there is some power to be gained here..... Any comments?
It is an impossible question due to the variables involved, but, a common rule of thumb says we need about 2.2 cfm of exhaust flow per each one hp produced.
This means that Flowmasters may not be a restriction on an engine that is producing 300 hp, but, they might be on one that is making 700.
We also have to remember that if we are running dual pipes that each muffler is only dealing with half the hp and that the entire system must be considered with regard to flow and not just the mufflers.
Many seem to feel that a 2.5" system begins to become a drag on the total power around 500 hp or so. This might be a more pressing problem than which muffler was chosen. There are plenty of charts online showing the flow potential of various pipe diameters.
Personally, I cannot stand the sound of flowmasters so I don't need much more reason to use Ultra Flos or similar. 
Steve
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Re: Dynomax mufflers VS Flowmasters
[Re: Kern Dog]
#1126506
12/03/11 02:25 PM
12/03/11 02:25 PM
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Joined: Aug 2005
Posts: 5,998
Salem
Grizzly
Moparts Proctologist
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Moparts Proctologist
Joined: Aug 2005
Posts: 5,998
Salem
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I agree with what was said about the level of horsepower you are at. If everything is laid out and the Dynomax can outflow the Flowmaster, is it worth it to cut your exhaust off (is it falling apart, does it need to be replaced?) and change everything out just to gain maybe 5 hp at WOT? A little bit of back-pressure is a good thing for everyday part-throttle driving. If it's balls to the wall WOT performance you are after, maybe a set of electric cut-outs would be the way to go instead. Off-topic, but I have a single Flowmaster on my 360 Magnum and that thing has at least 130,000+ miles on it and the case is still solid with no sign of leaks anywhere. Very happy with the build quality. 
Mo' Farts
Moderated by "tbagger".
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Re: Dynomax mufflers VS Flowmasters
[Re: pinkduster]
#1126508
12/03/11 03:15 PM
12/03/11 03:15 PM
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Joined: Nov 2007
Posts: 21,814
Kirkland, Washington
Pacnorthcuda
Too Many Posts
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Too Many Posts
Joined: Nov 2007
Posts: 21,814
Kirkland, Washington
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Quote:
Funny how the little "single" chamber Flowmaster wasn't on that list, just the two and three chambers. 
Maybe because the single chambers should be compared to "open headers" ???
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Re: Dynomax mufflers VS Flowmasters
[Re: Hotwheelsjr]
#1126510
12/03/11 03:57 PM
12/03/11 03:57 PM
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Joined: Jan 2006
Posts: 3,535
Canuckville
68Cbarge
master
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master
Joined: Jan 2006
Posts: 3,535
Canuckville
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 On a big block the Dynomax Super Turbos always sounded good. On my 318 small block,I run the Thrush Turbo's Flowmaster makes your car sound like a Chevelle or a Mustang,IMO. Like the threads here on wheels and tires,mufflers are a personal choice,so to each their own.
'68 Newport Custom Barge on a Budget!! BOAB
1973 Satellite WAGON! 318- 3 on the tree!!
2008 Chrysler 300c HEMI!
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Re: Dynomax mufflers VS Flowmasters
[Re: Kern Dog]
#1126513
12/03/11 10:38 PM
12/03/11 10:38 PM
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Joined: Jun 2003
Posts: 52,972
Romeo MI
MR_P_BODY
Master
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Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
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You need to understand that exhaust when HOT has a large volume(area)... most SB can use a 3 1/2" collector but as you go down stream the exhaust cools and reduces in volume(area) and the cooler the exhaust is the easier it is to control the sound... the farther back you put the muffler the better off you are... if you notice that the new Hemi cars the mufflers are at the back bumper.. we did that for power, sound and the reduction of back pressure 
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Re: Dynomax mufflers VS Flowmasters
[Re: pinkduster]
#1126514
12/04/11 03:14 AM
12/04/11 03:14 AM
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Joined: Jan 2003
Posts: 8,392
Highland, MI.
Sunroofcuda
master
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master
Joined: Jan 2003
Posts: 8,392
Highland, MI.
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Quote:
Funny how the little "single" chamber Flowmaster wasn't on that list, just the two and three chambers.
Here's what the single chamber FM looks like on the inside - looks like the exhaust instantly hits a wall upon arrival into the muffler. This causes a huge backlash, which is NOT good. I'd rather run a longer one! We tested 2 & 3 chamber, & Delta Flow FM's when I worked at Dynomax. The 2.5" AND 3" of these series FM's had flow rates of right around 350 sCFM. This translates into 318 loss-free HP with a dual exhaust setup. The Super Turbo 17748 (2.5" x 20" Hemi Super Turbo) has a flow rate of 415 sCFM, which = 378 loss-free HP dual exhaust. A straight-through stainless 2.5" Ultra Flow (#17289 offset/center) has a flow rate of 955 sCFM, which allows 868 loss-free HP on dual exhaust. This is the best flowing 2.5" x 20" oval, offset/center muffler on the market, bar none. The deflector setups inside the Flowmaster mufflers are horrible for flow - they totally kill the flow velocity of the exhaust. Buy them for sound, but not performance.
BTW, a Dynomax 3" x 20" offset/center oval Super Turbo #17769 flows 551 sCFM, which provides 500 loss-free HP on a dual exhaust. A 3" Welded Ultra Flow (20" body, offset/center) #17233 flows 1800 sCFM thus providing 1636 loss-free HP. You can decide from here!
No Man With A Good Car Needs To Be Justified
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Re: Dynomax mufflers VS Flowmasters
[Re: Sunroofcuda]
#1126516
12/04/11 03:31 AM
12/04/11 03:31 AM
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Joined: Jan 2003
Posts: 21,495
N.E. OHIO, USA
A12
Too Many Posts
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Too Many Posts
Joined: Jan 2003
Posts: 21,495
N.E. OHIO, USA
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Quote:
Quote:
Funny how the little "single" chamber Flowmaster wasn't on that list, just the two and three chambers.
Here's what the single chamber FM looks like on the inside - looks like the exhaust instantly hits a wall upon arrival into the muffler. This causes a huge backlash, which is NOT good. I'd rather run a longer one! We tested 2 & 3 chamber, & Delta Flow FM's when I worked at Dynomax. The 2.5" AND 3" of these series FM's had flow rates of right around 350 sCFM. This translates into 318 loss-free HP with a dual exhaust setup. The Super Turbo 17748 (2.5" x 20" Hemi Super Turbo) has a flow rate of 415 sCFM, which = 378 loss-free HP dual exhaust. A straight-through stainless 2.5" Ultra Flow (#17289 offset/center) has a flow rate of 955 sCFM, which allows 868 loss-free HP on dual exhaust. This is the best flowing 2.5" x 20" oval, offset/center muffler on the market, bar none. The deflector setups inside the Flowmaster mufflers are horrible for flow - they totally kill the flow velocity of the exhaust. Buy them for sound, but not performance.
BTW, a Dynomax 3" x 20" offset/center oval Super Turbo #17769 flows 551 sCFM, which provides 500 loss-free HP on a dual exhaust. A 3" Welded Ultra Flow (20" body, offset/center) #17233 flows 1800 sCFM thus providing 1636 loss-free HP. You can decide from here!
No wonder the GTX feels like the exhaust has a cork in it compared to the stainless Ultra-Flows.....that's it the Slowmasters are coming off in the Spring... 
MikeR
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Re: Dynomax mufflers VS Flowmasters
[Re: Sunroofcuda]
#1126518
12/04/11 01:51 PM
12/04/11 01:51 PM
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Joined: Nov 2004
Posts: 6,653
Near Reading PA USA
pinkduster
master
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master
Joined: Nov 2004
Posts: 6,653
Near Reading PA USA
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Quote:
Quote:
Funny how the little "single" chamber Flowmaster wasn't on that list, just the two and three chambers.
Here's what the single chamber FM looks like on the inside - looks like the exhaust instantly hits a wall upon arrival into the muffler. This causes a huge backlash, which is NOT good. I'd rather run a longer one! We tested 2 & 3 chamber, & Delta Flow FM's when I worked at Dynomax. The 2.5" AND 3" of these series FM's had flow rates of right around 350 sCFM. This translates into 318 loss-free HP with a dual exhaust setup. The Super Turbo 17748 (2.5" x 20" Hemi Super Turbo) has a flow rate of 415 sCFM, which = 378 loss-free HP dual exhaust. A straight-through stainless 2.5" Ultra Flow (#17289 offset/center) has a flow rate of 955 sCFM, which allows 868 loss-free HP on dual exhaust. This is the best flowing 2.5" x 20" oval, offset/center muffler on the market, bar none. The deflector setups inside the Flowmaster mufflers are horrible for flow - they totally kill the flow velocity of the exhaust. Buy them for sound, but not performance.
BTW, a Dynomax 3" x 20" offset/center oval Super Turbo #17769 flows 551 sCFM, which provides 500 loss-free HP on a dual exhaust. A 3" Welded Ultra Flow (20" body, offset/center) #17233 flows 1800 sCFM thus providing 1636 loss-free HP. You can decide from here!
Yeah, that's what the center in / dual out looks like, but what about the center in / center out? My car had the huge three chambers on it when I bought it. I recently switched to the little single chambers for two reasons. #1, I wanted to see if I'd pick up at the track, and #2, I wanted the car to be as loud and obnoxious as possible, but not run cut-outs. I picked up .02 and 1 mph at the track and yes, the car is crazy loud and 100% totally obnoxious.  Simply out of curiosity, I think I'm going to buy a set of these hopefullyflows that everybody here is in love with and see if they actually make any difference at the track without any other changes to the car. Now THAT would be a real world test.
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but quiet in side the cabin. Have never ran flowmasters but have some buddys that do and they sound good. I did start my car up when I 1st put it together and ran it around the block with open headers, it sounded like john force took a ride around the block. It rattled my neighbors windows and people I did not know came out of their houses to take a look. The dynomax units took care of that and never seemed to hurt the performance. I bought mine thru TTI.
