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Dynomax mufflers VS Flowmasters #1126500
12/03/11 03:09 AM
12/03/11 03:09 AM
Joined: Feb 2010
Posts: 18,493
Granite Bay CA
Kern Dog Offline OP
Striving for excellence
Kern Dog  Offline OP
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Granite Bay CA
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?

Re: Dynomax mufflers VS Flowmasters [Re: Kern Dog] #1126501
12/03/11 03:59 AM
12/03/11 03:59 AM
Joined: Feb 2005
Posts: 28,312
Cincinnati, Ohio
Challenger 1 Offline
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Cincinnati, Ohio
I'm not really sure about power, but I think the Dynomax mufflers sounds better than any Flowmaster muffler I've ever heard. imo

Re: Dynomax mufflers VS Flowmasters [Re: Kern Dog] #1126502
12/03/11 04:28 AM
12/03/11 04:28 AM
Joined: Aug 2011
Posts: 95
Idaho, USA
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White440 Offline
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Idaho, USA
I'm a fan of the tone that Flowmaster produces but I can definitely see how a straight (or straighter) flow muffler would have less resistance and inversions then a baffled design which would equate to better top end flow or so I would think.


"Full throttle until you see GOD then brake!" <img src="/ubbthreads/images/graemlins/drive.gif" alt="" /> Life's to short to ride the brakes!
Re: Dynomax mufflers VS Flowmasters [Re: Challenger 1] #1126503
12/03/11 04:30 AM
12/03/11 04:30 AM
Joined: Jan 2003
Posts: 6,570
San Francisco Ca
SCATPK Offline
master
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San Francisco Ca
I have a pair of dynomax muffs on my car and they give it a nice tone at idle and full throttle 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.

Re: Dynomax mufflers VS Flowmasters [Re: SCATPK] #1126504
12/03/11 10:28 AM
12/03/11 10:28 AM
Joined: Sep 2003
Posts: 1,465
Carson City, NV
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babarracuda Offline
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Carson City, NV
I hate flow masters, they sound hollow. They have that Mustang sound. I have Dynomax super tubos with 3" exhaust. Being an old fart I added 12" Summit glass packs because I didn't like the drone inside the car when cruising aroung 2000 RPM. My younger friends loved the sound all the way through the RPM range. When I nail it going on the freeway ramp next to Home Depot, I always get at least one comment the next time I go back to the store.

Re: Dynomax mufflers VS Flowmasters [Re: Kern Dog] #1126505
12/03/11 11:58 AM
12/03/11 11:58 AM
Joined: Oct 2010
Posts: 183
Eden, Texas
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Strawdawg Offline
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Eden, Texas
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
Re: Dynomax mufflers VS Flowmasters [Re: Kern Dog] #1126506
12/03/11 02:25 PM
12/03/11 02:25 PM
Joined: Aug 2005
Posts: 5,997
Salem
Grizzly Offline
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Salem
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".
Re: Dynomax mufflers VS Flowmasters [Re: Grizzly] #1126507
12/03/11 02:32 PM
12/03/11 02:32 PM
Joined: Nov 2004
Posts: 6,653
Near Reading PA USA
pinkduster Offline
master
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Near Reading PA USA
Funny how the little "single" chamber Flowmaster wasn't on that list, just the two and three chambers.

Re: Dynomax mufflers VS Flowmasters [Re: pinkduster] #1126508
12/03/11 03:15 PM
12/03/11 03:15 PM
Joined: Nov 2007
Posts: 21,808
Kirkland, Washington
Pacnorthcuda Offline
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Kirkland, Washington
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" ???

Re: Dynomax mufflers VS Flowmasters [Re: Pacnorthcuda] #1126509
12/03/11 03:20 PM
12/03/11 03:20 PM
Joined: Nov 2003
Posts: 10,693
Surface of the Sun, AZ
Hotwheelsjr Offline
I Live Here
Hotwheelsjr  Offline
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Surface of the Sun, AZ
Easy comparison --

Dynomax:



Flowmaster:


Re: Dynomax mufflers VS Flowmasters [Re: Hotwheelsjr] #1126510
12/03/11 03:57 PM
12/03/11 03:57 PM
Joined: Jan 2006
Posts: 3,535
Canuckville
68Cbarge Offline
master
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Canuckville

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!
Re: Dynomax mufflers VS Flowmasters [Re: 68Cbarge] #1126511
12/03/11 10:06 PM
12/03/11 10:06 PM
Joined: Jan 2003
Posts: 27,421
Balt. Md
3
383man Offline
Too Many Posts
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Posts: 27,421
Balt. Md
Since I race my car thru the mufflers it only made sense to run the Dyno-Max Ultra-Flows since they are straight thru. I like the sound and performance of the Dyno-Max.

I can tell you we have the Flow Master 40's on my sons Dart and it picks up 2 tenths when uncapped. Ron

Re: Dynomax mufflers VS Flowmasters [Re: 383man] #1126512
12/03/11 10:12 PM
12/03/11 10:12 PM
Joined: Dec 2004
Posts: 5,278
San Jose, California
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DennisH Offline
Vacation
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San Jose, California
Dynomax following the QTP's and TTI's.

Re: Dynomax mufflers VS Flowmasters [Re: Kern Dog] #1126513
12/03/11 10:38 PM
12/03/11 10:38 PM
Joined: Jun 2003
Posts: 52,972
Romeo MI
MR_P_BODY Offline
Master
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Posts: 52,972
Romeo MI
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


Re: Dynomax mufflers VS Flowmasters [Re: pinkduster] #1126514
12/04/11 03:14 AM
12/04/11 03:14 AM
Joined: Jan 2003
Posts: 8,390
Highland, MI.
Sunroofcuda Offline
master
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Highland, MI.
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
Re: Dynomax mufflers VS Flowmasters [Re: MR_P_BODY] #1126515
12/04/11 03:22 AM
12/04/11 03:22 AM
Joined: Jan 2003
Posts: 21,474
N.E. OHIO, USA
A12 Online content
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N.E. OHIO, USA
long story short I wanted a pair of mufflers for my '68 road runner a few years back and thought that I would do a set of Flowmasters at first but someone that ran F.A.S.T told me to go with the Dynomax Ultra-Flows so I did and they worked great and sounded even better.....although I was kind of curious how the imfamous Flowmasters would have sounded..........fast forward to getting the '69 GTX and it having a new exhaust system that was already on there by the previous owner with Flowmasters.........I CAN'T STAND THEM!!!!, my wife CAN'T STAND THEM!!!!....anyone want a pair of Blowmasters???? I'll take a pair of Dynomax Ultra Flows over anything now....and I think they are of the same straight through design with a perforated core and (glass wool) packing as the original factory mufflers if I'm not mistaken, so no wonder why they sound like the car was supposed to sound

Re: Dynomax mufflers VS Flowmasters [Re: Sunroofcuda] #1126516
12/04/11 03:31 AM
12/04/11 03:31 AM
Joined: Jan 2003
Posts: 21,474
N.E. OHIO, USA
A12 Online content
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Too Many Posts

Joined: Jan 2003
Posts: 21,474
N.E. OHIO, USA
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

6949733-DSC04673aaaa.jpg (1068 downloads)
Re: Dynomax mufflers VS Flowmasters [Re: A12] #1126517
12/04/11 04:18 AM
12/04/11 04:18 AM
Joined: Jan 2003
Posts: 1,607
Western Washington
Sixgun Offline
top fuel
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Posts: 1,607
Western Washington
Used to work @ NAPA, and kind of got the straight from the Walker Rep.
Then was @ MATS a few years ago, and they stated clearly that Dynomax is the only true "zero loss" muffler.(Not sure which exact ones, probably the ultra flows)

Re: Dynomax mufflers VS Flowmasters [Re: Sunroofcuda] #1126518
12/04/11 01:51 PM
12/04/11 01:51 PM
Joined: Nov 2004
Posts: 6,653
Near Reading PA USA
pinkduster Offline
master
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Near Reading PA USA
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.

Re: Dynomax mufflers VS Flowmasters [Re: pinkduster] #1126519
12/04/11 03:34 PM
12/04/11 03:34 PM
Joined: Nov 2004
Posts: 6,653
Near Reading PA USA
pinkduster Offline
master
pinkduster  Offline
master

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Near Reading PA USA
After an exhaustive image search on Google and Bing, I have determined that the image posted by sunroofcuda is NOT a Flowmaster muffler. It is a Flowsound muffler. I was unanble to find a cut away image of a center in / center out Flowmaster race muffler. However, I did find this image of a single chamber Flowmaster. So I assume the center in / center out would be similar.



Regardless, I'll try some Ultra Flows next season. My exhaust is set up so I can easily change from my little single chambers and dumps, to the three chambers and dumps or tailpipes. I'll just add a third option to the mix. And I'd be happy if it would pick some ET.

Re: Dynomax mufflers VS Flowmasters [Re: pinkduster] #1126520
12/04/11 03:44 PM
12/04/11 03:44 PM
Joined: Jan 2003
Posts: 8,390
Highland, MI.
Sunroofcuda Offline
master
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Highland, MI.
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
Re: Dynomax mufflers VS Flowmasters [Re: Sunroofcuda] #1126521
12/04/11 05:56 PM
12/04/11 05:56 PM
Joined: Jul 2007
Posts: 271
MO, USA
Tom Hand Offline
enthusiast
Tom Hand  Offline
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Posts: 271
MO, USA
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.
Re: Dynomax mufflers VS Flowmasters [Re: Tom Hand] #1126522
12/04/11 06:19 PM
12/04/11 06:19 PM
Joined: Oct 2007
Posts: 288
Birmingham, England
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Mick70RR Offline
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Birmingham, England
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
Re: Dynomax mufflers VS Flowmasters [Re: Mick70RR] #1126523
12/04/11 11:36 PM
12/04/11 11:36 PM
Joined: Nov 2004
Posts: 6,653
Near Reading PA USA
pinkduster Offline
master
pinkduster  Offline
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Near Reading PA USA
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.

Re: Dynomax mufflers VS Flowmasters [Re: pinkduster] #1126524
12/05/11 01:07 AM
12/05/11 01:07 AM
Joined: Jan 2003
Posts: 8,390
Highland, MI.
Sunroofcuda Offline
master
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master

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Highland, MI.
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
Re: Dynomax mufflers VS Flowmasters [Re: Sunroofcuda] #1126525
12/06/11 12:53 AM
12/06/11 12:53 AM
Joined: Feb 2010
Posts: 18,493
Granite Bay CA
Kern Dog Offline OP
Striving for excellence
Kern Dog  Offline OP
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Posts: 18,493
Granite Bay CA
I enjoy the sound of Flowmaster equipped cars. I must be one of the few that have a "drone-free" set of mufflers. I have a 440/493 with a 292/509 cam, TTI 2" headers, 2 1/2 pipes with 42451 Flowmasters and full tailpipes. Simply put, I found the chart listed in that other muffler post quite interesting and it made me curious. My exhaust system is 8 years old but looks and sounds new. I am not looking to replace rusty muffers here, I was just interested in what the flow rates translate to in terms of power.

Re: Dynomax mufflers VS Flowmasters [Re: Tom Hand] #1126526
12/07/11 08:27 AM
12/07/11 08:27 AM
Joined: Mar 2010
Posts: 984
Tennessee
H
Hemi ragtop Offline
super stock
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H

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Posts: 984
Tennessee
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?

Re: Dynomax mufflers VS Flowmasters [Re: Hemi ragtop] #1126527
12/08/11 12:12 AM
12/08/11 12:12 AM
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MO, USA
Tom Hand Offline
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Hemi, you know, we never got a chance to test them but they will end up similar to the Dynomax Super Turbo offset in center out with a tad less airflow. The reason I say this is they are a reverse flow muffler (I believe) and they will act similarly to other three pass reverse flow mufflers except they have larger internal pass tubes that will drop the back pressure, lower the sound frequency and raise the sound level slightly. Without the patented "Flow Directors" however, they will lose a bit of air flow through them.

Accurate is a fine bunch of folks and I bet they have some actual numbers to share, you might email them and ask and please share if you find out.
Tom Hand

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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Highland, MI.
Sunroofcuda Offline
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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
Re: Dynomax mufflers VS Flowmasters [Re: Sunroofcuda] #1126529
12/08/11 08:51 AM
12/08/11 08:51 AM
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Royersford, PA
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bschargerse Offline
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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."
Re: Dynomax mufflers VS Flowmasters [Re: bschargerse] #1126530
12/08/11 11:09 AM
12/08/11 11:09 AM
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Marysville, O-H-I-O
70Cuda383 Offline
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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**
Re: Dynomax mufflers VS Flowmasters [Re: 70Cuda383] #1126531
12/08/11 05:19 PM
12/08/11 05:19 PM
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dogdays Offline
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My '64Dog has 2 1/2" Super Turbos 17748 or 9s (I can never remember which) running from the stock Poly manifolds out in front of the rear tires.
"Weedburners"
I have received several compliments from strangers who said it had "just the right sound". The pipes are probably too big for the 318 but I like'em that way.
If I do it again I'll extend pipes to the rear bumper to cut noise a little on those 600 mile trips.

R.

PS: Thanks for the measured data, it is worth much more than the butt dyno.

Re: Dynomax mufflers VS Flowmasters [Re: Sunroofcuda] #1126532
12/08/11 08:02 PM
12/08/11 08:02 PM
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Posts: 271
MO, USA
Tom Hand Offline
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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.
Re: Dynomax mufflers VS Flowmasters [Re: Sunroofcuda] #1126533
12/09/11 09:40 PM
12/09/11 09:40 PM
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Kudakidd Offline
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How do Super Turbos compare to Ultra flows? BTW, I have Super Turbos on my Duster right now. Will the Ultras be louder and provide more HP?

Re: Dynomax mufflers VS Flowmasters [Re: Kudakidd] #1126534
12/10/11 01:35 AM
12/10/11 01:35 AM
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Eden, Texas
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Strawdawg Offline
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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
Re: Dynomax mufflers VS Flowmasters [Re: Strawdawg] #1126535
12/12/11 12:59 PM
12/12/11 12:59 PM
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IL
furious70 Offline
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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
Re: Dynomax mufflers VS Flowmasters [Re: furious70] #1126536
12/28/11 07:07 PM
12/28/11 07:07 PM
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IL
furious70 Offline
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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
Re: Dynomax mufflers VS Flowmasters [Re: Sunroofcuda] #1126537
12/28/11 09:01 PM
12/28/11 09:01 PM
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Kudakidd Offline
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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!

Re: Dynomax mufflers VS Flowmasters [Re: furious70] #1126538
12/28/11 09:05 PM
12/28/11 09:05 PM
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Central NC
gch Offline
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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).

Re: Dynomax mufflers VS Flowmasters [Re: gch] #1126539
12/28/11 11:04 PM
12/28/11 11:04 PM
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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

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493 Indy EZ's by Nick at Compu-Flow
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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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Royersford, PA
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bschargerse Offline
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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."
Re: Dynomax mufflers VS Flowmasters [Re: bschargerse] #1126541
12/29/11 03:13 PM
12/29/11 03:13 PM
Joined: Jan 2003
Posts: 8,390
Highland, MI.
Sunroofcuda Offline
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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
Re: Dynomax mufflers VS Flowmasters [Re: Sunroofcuda] #1126542
12/29/11 09:22 PM
12/29/11 09:22 PM
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Rittman Ohio
fourgearsavoy Offline
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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

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64 Plymouth Savoy
493 Indy EZ's by Nick at Compu-Flow
5-Speed Richmond faceplate Liberty box
Dana 60
Re: Dynomax mufflers VS Flowmasters [Re: fourgearsavoy] #1126543
12/29/11 11:21 PM
12/29/11 11:21 PM
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Weddington, N.C.
Streetwize Offline
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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.

WIZE

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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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Highland, MI.
Sunroofcuda Offline
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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
Re: Dynomax mufflers VS Flowmasters [Re: Sunroofcuda] #1126545
12/30/11 02:47 AM
12/30/11 02:47 AM
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Michigan
MarkZ Offline
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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
Re: Dynomax mufflers VS Flowmasters [Re: Sunroofcuda] #1126546
12/30/11 10:45 PM
12/30/11 10:45 PM
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Rittman Ohio
fourgearsavoy Offline
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Quote:

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



Thanks for your expertise Eric The mufflers I seen were the 17769 mufflers.I am just looking for something quieter than the 40 series 2 chamber flowmasters I am running now.
Gus

6992835-savoyburnout.jpg (193 downloads)

64 Plymouth Savoy
493 Indy EZ's by Nick at Compu-Flow
5-Speed Richmond faceplate Liberty box
Dana 60
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