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: 5,997 Salem
Grizzly
Moparts Proctologist
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Moparts Proctologist
Joined: Aug 2005
Posts: 5,997
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: 21,808 Kirkland, Washington
Pacnorthcuda
Too Many Posts
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Posts: 21,808
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: 8,390 Highland, MI.
Sunroofcuda
master
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master
Joined: Jan 2003
Posts: 8,390
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: 21,474 N.E. OHIO, USA
A12
Too Many Posts
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Too Many Posts
Joined: Jan 2003
Posts: 21,474
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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Re: Dynomax mufflers VS Flowmasters
[Re: pinkduster]
#1126520
12/04/11 03:44 PM
12/04/11 03:44 PM
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Joined: Jan 2003
Posts: 8,390 Highland, MI.
Sunroofcuda
master
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master
Joined: Jan 2003
Posts: 8,390
Highland, MI.
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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.
I couldn't find an internal shot of anything other than the single-in, dual-out single chamber. But it will have the trademark Flowmaster "wall of death" first deflector. ANY muffler that has an obstruction in the flowpath, no matter what it looks like - I don't care if it comes from NASA, an obstruction causes flow impedence. Flow impedence = restriction. To certain degrees, some of this will not adversely affect your performance, it depends on your HP, the pipe diameter of your system, etc. Too small of diameter pipes will cause restriction as well, so remember that even though the pipes are "straight through." I wish I would have understood this exhaust stuff back in 1983 when I replaced my mufflers on my '71 Hemi Charger. I thought - OK, I got a Hemi car, so I should replace the original mufflers with Hemi mufflers! So I bought a pair of "Hemi" mufflers from Mitchell Motors. The ones I received were shorter than the originals (originals were 20" long bodies). I put them on anyway & I could tell they were restrictive - I mean you could hear it & feel it. If I had known something about exhaust, I would have put on a pair of Walker Redline Z mufflers (which later evolved into the Dynomax Super Turbos).
Dynomax's head of performance exhaust engineering has been an engineer for Walker/Dynomax since about 1974, so he's lived through many muffler designs, & seen lots of mufflers come & go. I learned a lot from him, & contributed a lot to Dynomax when I was there also. There are about a dozen Dynomax mufflers that I suggested we build back 11 years ago, & they were all added to the line. Then I suggested we add a new series of QUALITY mufflers to the Thrush line rather than skirt the brand - hell I contended that more people knew the Thrush muffler brand than Dynomax! Why buy out a company like Thrush & then do nothing with it? It didn't make sense to either of us. Tenneco did eventually add a new family of welded Thrush mufflers, so this may have come from my idea I don't know - I had left the company in 2001. Then the bean counters at Tenneco decided one Friday to kill the Thrush Turbo Tube chambered mufflers around 2000. This was a big mistake. It led to me eventually making MY mufflers - the chambered POWERSTICK. They are based on the same premise of the Turbo Tube, but mine flow a LOT better, & are much more heavily constructed. Plus, I have a family of TRUE 3" versions that sound much more brutal than any muffler on the market. If you want something really different, & really aggressive, you may want to look into them. The thing that always amused me about real chambered exhaust tubes, was the way they sounded so unique. The crimps in the outside casing of the mufflers are what do the sound tuning. They create a sound wave anamoly that no other muffler designs can duplicate.
No Man With A Good Car Needs To Be Justified
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Re: Dynomax mufflers VS Flowmasters
[Re: Sunroofcuda]
#1126521
12/04/11 05:56 PM
12/04/11 05:56 PM
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Joined: Jul 2007
Posts: 271 MO, USA
Tom Hand
enthusiast
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enthusiast
Joined: Jul 2007
Posts: 271
MO, USA
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Pinkduster, not sure but the list they refer to may be the one Dad and I generated with all of our testing. We chose to use only mufflers that were similar to stock sized mufflers or in the range of what were then being called turbo-sized. Mainly, we used the 14" and 20" body-sized case. Plus we had no reason to use single chamber mufflers as they are so loud no one could possibly stand to drive around with them too long or they might go deaf. :) The other reason UltraFlo mufflers work so well is that they have inside diameter pipe that is actually slightly larger than the inlet and outlet bushings. We indeed saw (fantastic performance and) higher than 100% airflow numbers when we tested them as compared to equivalent lengths of straight, unperforated pipe. Hope this makes sense. Tom Hand
Last edited by Tom Hand; 12/04/11 06:04 PM.
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Re: Dynomax mufflers VS Flowmasters
[Re: Tom Hand]
#1126522
12/04/11 06:19 PM
12/04/11 06:19 PM
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Joined: Oct 2007
Posts: 288 Birmingham, England
Mick70RR
enthusiast
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enthusiast
Joined: Oct 2007
Posts: 288
Birmingham, England
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I just like the sound of Flowmasters, that's why I use them. I fitted electric cutouts just after the collectors and my ET/mph is the same with them open or closed so they are not restrictive at my HP level. I use 3" delta 40's and 3" pipe all the way to the bumper. Here's a nice clip of a Charger with Flowmasters. http://www.youtube.com/watch?v=Hu8_uxk4hiM
1970 Road Runner
505 cid
MCH CNC ported Stealth heads
MP 528 camshaft
4 speed
GV overdrive
11.98 @ 117 on street treads
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Re: Dynomax mufflers VS Flowmasters
[Re: Mick70RR]
#1126523
12/04/11 11:36 PM
12/04/11 11:36 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:
I just like the sound of Flowmasters, that's why I use them. I fitted electric cutouts just after the collectors and my ET/mph is the same with them open or closed so they are not restrictive at my HP level. I use 3" delta 40's and 3" pipe all the way to the bumper. Here's a nice clip of a Charger with Flowmasters. http://www.youtube.com/watch?v=Hu8_uxk4hiM
Nice! I'm one of the few that actually LIKE the sound of Flowmasters too. However, I'll try a set of the Ultra Flos next season. If they can get me over the 11.80s hump and into the 11.70s or .60s just by changing mufflers, then I'll be a Dynomax convertee. And I'll be sure to post my results on here.
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Re: Dynomax mufflers VS Flowmasters
[Re: pinkduster]
#1126524
12/05/11 01:07 AM
12/05/11 01:07 AM
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Joined: Jan 2003
Posts: 8,390 Highland, MI.
Sunroofcuda
master
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master
Joined: Jan 2003
Posts: 8,390
Highland, MI.
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Truth be told, I like the way they sound too on most applications. One of my buddies has a 3" system on a '73 Rallye Charger & the car sounds great - REALLY nice! BUT, a few years ago we rode to a show in it 35 miles away & I'll tell you, the resonance was bad enough that I had a headache by the time we got there, plus my ears were ringing. Flowmasters do have the resonance thing really going on bad.
No Man With A Good Car Needs To Be Justified
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Re: Dynomax mufflers VS Flowmasters
[Re: Tom Hand]
#1126526
12/07/11 08:27 AM
12/07/11 08:27 AM
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Joined: Mar 2010
Posts: 984 Tennessee
Hemi ragtop
super stock
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super stock
Joined: Mar 2010
Posts: 984
Tennessee
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Quote:
Pinkduster, not sure but the list they refer to may be the one Dad and I generated with all of our testing.
We chose to use only mufflers that were similar to stock sized mufflers or in the range of what were then being called turbo-sized. Mainly, we used the 14" and 20" body-sized case. Plus we had no reason to use single chamber mufflers as they are so loud no one could possibly stand to drive around with them too long or they might go deaf. :)
The other reason UltraFlo mufflers work so well is that they have inside diameter pipe that is actually slightly larger than the inlet and outlet bushings. We indeed saw (fantastic performance and) higher than 100% airflow numbers when we tested them as compared to equivalent lengths of straight, unperforated pipe.
Hope this makes sense. Tom Hand
All this talk about mufflers is interesting. Some of you are obviously very well infomrmed. I just wonder if any of you have tested Accurate LTD HEMI mufflers and what where the results?
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Re: Dynomax mufflers VS Flowmasters
[Re: Tom Hand]
#1126528
12/08/11 01:38 AM
12/08/11 01:38 AM
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Joined: Jan 2003
Posts: 8,390 Highland, MI.
Sunroofcuda
master
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master
Joined: Jan 2003
Posts: 8,390
Highland, MI.
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Yeah, I believe the Accurate Hemi mufflers are 3-tubes. They won't have the patented Super Turbo flow directors (bank turns) so that will slow things down internally. I've never looked inside an Accurate muffler to note the dia. of the flow tubes. If they neck-down like OE mufflers, that will also affect the flow quite a bit. Tom is on-target with his comments.
I'm guessing the Accurate Hemi mufflers will flow around 300-350 sCFM if tested the same way the Dynomax mufflers are tested.
To put into perspective, I brought in an NOS AAR/T/A muffler one day when I worked for Tenneco (mufflers for my AAR) & we flow tested it. It had a flow rate of 175 sCFM (BAD!). Then our head engineer designed a couple & our prototype dept. built them (stainless too). They did not have any flow directors on-hand when they built them, but they were built with larger cores. The ones they built had flow rates of 375 sCFM - a HUGE improvement. I tried to get these into production but to no avail............ I don't have my car close to running yet, so I don't know what they sound like. I can't wait though.
Last edited by Sunroofcuda; 12/08/11 01:45 AM.
No Man With A Good Car Needs To Be Justified
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Re: Dynomax mufflers VS Flowmasters
[Re: Sunroofcuda]
#1126529
12/08/11 08:51 AM
12/08/11 08:51 AM
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Joined: Jun 2005
Posts: 2,507 Royersford, PA
bschargerse
master
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master
Joined: Jun 2005
Posts: 2,507
Royersford, PA
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Accurate sells a Hemi High-Flow muffler also. I wonder how that would compare... I have a set for my Charger that someday will get installed.
Brian - 1971 Dodge Challenger "The Dodge, which was practically stock, just left the Mustang like you wouldn't believe."
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Re: Dynomax mufflers VS Flowmasters
[Re: bschargerse]
#1126530
12/08/11 11:09 AM
12/08/11 11:09 AM
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Joined: Oct 2003
Posts: 21,345 Marysville, O-H-I-O
70Cuda383
Too Many Posts
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Posts: 21,345
Marysville, O-H-I-O
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I'm a fan of the powersticks myself. awesome sound, but they can be loud. my dakota has 2 of the 31" x 3" versions, welded end to end, and I left that dumped at first. it sounded great, but my first long trip with it left my ears bleeding! I dug out some foamie ear plugs and stuck them in to finish the trip.
that could be because I had them dumped infront of the axle, could be tube length left a resonance, I don't know. I cut off the dump, added a 12" glasspack and then took the exhaust up and over the axle, and now it's angled down/back at 45 degrees so the sound shoots out from under the truck. just about everywhere I go, people come up and comment on how good it sounds, one guy even ran up to me as we were leaving Carlisle and wanted to know where I bought my "cat back" from. his eyes kind of glazed over with the "oh crap" look when I told him it wasn't a cat-back, but a full custom exhaust, but then seemed to come back a little bit when I told him I only had about $250 wrapped up in the whole system (he had been shopping cat-back exhausts which retail for some stupid number, like $500 for some pipe, a muffler, and tips.)
**Photobucket sucks**
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Re: Dynomax mufflers VS Flowmasters
[Re: Sunroofcuda]
#1126532
12/08/11 08:02 PM
12/08/11 08:02 PM
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Joined: Jul 2007
Posts: 271 MO, USA
Tom Hand
enthusiast
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enthusiast
Joined: Jul 2007
Posts: 271
MO, USA
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Dogdays, 17748s are center outlets so that is likely what you run too. I have some spares around. And as Eric said, the three pass mufflers are pretty similar. For reference, the old true Corvair Turbo 2.5" inlet/outlet muffler flows about 54% of an open pipe. The SuperTurbos, around 70% or so, UltraFlos around 100% and typical DeltaFlow Flowmaster-type mufflers around 53% or so, depending upon inlet/outlet configuration and length. The patented flow directors do add a lot to the air flow potential through the three pass SuperTurbo mufflers even if the pass tube diameters are slightly smaller than inlet and outlet bushings. The old stock mufflers are in the range of 35% or so. My VOE is about 33% then switches up to about 55% or so. Not super hot-rod performance but better than some others you can buy and I have the option of running quieter than stock but as loud as chambered mufflers. :) Tom Hand
Last edited by Tom Hand; 12/08/11 08:07 PM.
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Re: Dynomax mufflers VS Flowmasters
[Re: Kudakidd]
#1126534
12/10/11 01:35 AM
12/10/11 01:35 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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The post above yours gives a comparison as to how they relate. If you make enuf power, they will allow it with less restriction, but, you have to be making serious hp.
IMO, they sound different, but, not necessarily that much louder. Again, a lot of the "sound" depends upon engine combination, in my experience.
Steve
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Re: Dynomax mufflers VS Flowmasters
[Re: Strawdawg]
#1126535
12/12/11 12:59 PM
12/12/11 12:59 PM
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Joined: Nov 2006
Posts: 2,252 IL
furious70
top fuel
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top fuel
Joined: Nov 2006
Posts: 2,252
IL
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Anyone know who makes Summit's turbo mufflers and how well they flow? I've got their 3" ones on my Fury, and some people on the turbo board suggested they may be part of my high back pressure measurements on my turbo system.
70 Sport Fury 68 Charger 69 Coronet 72 RR
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Re: Dynomax mufflers VS Flowmasters
[Re: furious70]
#1126536
12/28/11 07:07 PM
12/28/11 07:07 PM
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Joined: Nov 2006
Posts: 2,252 IL
furious70
top fuel
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top fuel
Joined: Nov 2006
Posts: 2,252
IL
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Is there much of a performance difference between the 14" and 20" bodies on the superturbos? Much of a decibel difference?
70 Sport Fury 68 Charger 69 Coronet 72 RR
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Re: Dynomax mufflers VS Flowmasters
[Re: Sunroofcuda]
#1126537
12/28/11 09:01 PM
12/28/11 09:01 PM
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Joined: Jan 2003
Posts: 7,844 Witness Protection Program
Kudakidd
master
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master
Joined: Jan 2003
Posts: 7,844
Witness Protection Program
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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!
Great write up!
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Re: Dynomax mufflers VS Flowmasters
[Re: furious70]
#1126538
12/28/11 09:05 PM
12/28/11 09:05 PM
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Joined: Mar 2005
Posts: 3,131 Central NC
gch
master
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master
Joined: Mar 2005
Posts: 3,131
Central NC
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Quote:
Is there much of a performance difference between the 14" and 20" bodies on the superturbos? Much of a decibel difference?
See above.
The longer case will flow better and be quieter(if that's what you want).
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Re: Dynomax mufflers VS Flowmasters
[Re: gch]
#1126539
12/28/11 11:04 PM
12/28/11 11:04 PM
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Joined: Dec 2004
Posts: 10,550 Rittman Ohio
fourgearsavoy
I Live Here
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I Live Here
Joined: Dec 2004
Posts: 10,550
Rittman Ohio
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Most of this discussion is based around 2 1/2" exhaust but I have 3" on my car and I have plenty of room for the largest case they make. Is there a Dynomax muffler longer than 20" with a 3" in and out? Gus
64 Plymouth Savoy 493 Indy EZ's by Nick at Compu-Flow 5-Speed Richmond faceplate Liberty box Dana 60
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Re: Dynomax mufflers VS Flowmasters
[Re: fourgearsavoy]
#1126540
12/29/11 11:35 AM
12/29/11 11:35 AM
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Joined: Jun 2005
Posts: 2,507 Royersford, PA
bschargerse
master
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master
Joined: Jun 2005
Posts: 2,507
Royersford, PA
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Gus, there is a 6" round Ultra Flow that is 30" long, part # 17299, 3" I/O. I'm not sure if that case is too large in diameter.
In oval mufflers there is an Ultra Flow welded muffler, part #17235, 24" long case, 3" I/O side/center. Body is 4-1/4" x 9-3/4".
That's all I could find in my Dynomax catalog.
Brian - 1971 Dodge Challenger "The Dodge, which was practically stock, just left the Mustang like you wouldn't believe."
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Re: Dynomax mufflers VS Flowmasters
[Re: bschargerse]
#1126541
12/29/11 03:13 PM
12/29/11 03:13 PM
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Joined: Jan 2003
Posts: 8,390 Highland, MI.
Sunroofcuda
master
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master
Joined: Jan 2003
Posts: 8,390
Highland, MI.
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What is it going under? Also, do you have room to run multiple mufflers - 2 per side? You can run multiple Ultra Flows & knock-out more noise without hurting backpressure. Also, do you want stainless or is aluminized construction OK?
No Man With A Good Car Needs To Be Justified
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Re: Dynomax mufflers VS Flowmasters
[Re: Sunroofcuda]
#1126542
12/29/11 09:22 PM
12/29/11 09:22 PM
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Joined: Dec 2004
Posts: 10,550 Rittman Ohio
fourgearsavoy
I Live Here
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I Live Here
Joined: Dec 2004
Posts: 10,550
Rittman Ohio
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Eric they are going under my 64 Savoy.I seen a set under a Daytona over at B/E&A Restorations that came with the 3" flowmaster system that looked really nice.I would rather stay with one long large oval muffler if at all possible. Gus
64 Plymouth Savoy 493 Indy EZ's by Nick at Compu-Flow 5-Speed Richmond faceplate Liberty box Dana 60
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Re: Dynomax mufflers VS Flowmasters
[Re: fourgearsavoy]
#1126543
12/29/11 11:21 PM
12/29/11 11:21 PM
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Joined: Jan 2003
Posts: 9,866 Weddington, N.C.
Streetwize
master
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master
Joined: Jan 2003
Posts: 9,866
Weddington, N.C.
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Free air flow is not the same as high pressure exhaust flow that has pressure pulses behind it so you have to take advertized numbers as what they are....advertisements. Behind each pulse is a vaccuum wave...which left to itself is Filled (equalized) by atmospheric air pressure 14.7psi at sea level, A true scintific means to demonstrate back-pressure that might be detrimental to the performance of the engine would be to measure the pressure increase against the muffler CASE as engine RPM increases. In all cases heat is absorbed into the exhaust system and velocity drops to the point where the pressure wave equalizes with ambient air pressure (again 14.7psi) where it meats thew outside air. Itf the exhaust flow was indeed RESTRICTED from passing fast enough to satisfy the discharge of the motor, the back pressure would register as an increase in case pressure since the passing air can't get out of the muffler as fast as it's coming in. I suspect the pressure measurements /extremese you would read on most well-designed low restriction high flow systems are nowhere near as dramatic as many people might think....a lot of heat energy is dissipated from the system before it ever reaches the muffler...temperatures drop substantially from ~1800-2000 F at the exhaust valve by the time they reach the tailpipes on a full exhaust car those Chrysler engineers were pretty clever took full advantage of that dissipation of energy by dropping the tailpipe size vs the headpipe and many subsequent tests have proved this as well. The muffler is only one component of the system, and all a muffler is is a compromise between sound and performance. But that said I'd venture to bet that you have to accept a lot more DB's of sound for a relatively small amount of 'net-net' enhancement of performance. If Feeling and Sounding faster ALWAYS MEANT faster there wouldn't be nearly as many PITA hondas and Harleys making lots of noise and yet not accelerating any faster than my wife's poor little CR-V from a stoplight
Last edited by Streetwize; 12/29/11 11:53 PM.
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Re: Dynomax mufflers VS Flowmasters
[Re: Streetwize]
#1126544
12/30/11 12:28 AM
12/30/11 12:28 AM
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Joined: Jan 2003
Posts: 8,390 Highland, MI.
Sunroofcuda
master
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master
Joined: Jan 2003
Posts: 8,390
Highland, MI.
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WIZE - even the engineers at Dynomax don't talk like that!
Gus, here's my recommendation:
Run a pair of Ultra Flow Welded #17233 (20" bodied), or #17235 (24" bodied). Depends on what will fit under the back seat area. I can build you a pair of 4" diameter resonators for extra noise control at the rear if you have room. The longer they are, the more noise they will knock out. They will have 3" necks & cores, plus a GOOD quality fiberglass packing that will not blow out. I can build them in any length - up to 40" long.
The car you saw with the TTI system was probably running Super Turbos #17793's or 17769's. I have a buddy with a '70 Challenger 440+6 that is running those in his TTI system. The packing blankets broke-down in the mufflers & now the car is hideously loud - TOO loud! Heck, my 3" chambered mufflers would be quieter than those now.
-Eric
No Man With A Good Car Needs To Be Justified
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Re: Dynomax mufflers VS Flowmasters
[Re: Sunroofcuda]
#1126545
12/30/11 02:47 AM
12/30/11 02:47 AM
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Joined: Jan 2005
Posts: 4,369 Michigan
MarkZ
Worthy
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Worthy
Joined: Jan 2005
Posts: 4,369
Michigan
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I've got Flowmaster 40 series mufflers on my Fifth Avenue with a 9.5:1, Eddie headed 360. The exhaust is 2.5" with cutouts under the doors. Honestly, I can't feel any bit of a difference in power with the car when going through the mufflers compared to the cutouts. The motor should be good (never had it on a dyno) for 380HP. Now the drone, well, that's another issue.
1987 Fifth Avenue - 512/518/D60
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