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Re: Dynomax Super Turbos Suck
[Re: 69Cuda340S]
#1116841
11/19/11 01:02 PM
11/19/11 01:02 PM
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Joined: Oct 2003
Posts: 21,345
Marysville, O-H-I-O
70Cuda383
Too Many Posts
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Too Many Posts
Joined: Oct 2003
Posts: 21,345
Marysville, O-H-I-O
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looks like a sacrifice in performance for optimum in/out locations...must be for certain cars? but for all that muffler is, why not replace sections of straight pipe with 3 glass pack resonators!
**Photobucket sucks**
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Re: Dynomax Super Turbos Suck
[Re: 70Cuda383]
#1116842
11/19/11 01:38 PM
11/19/11 01:38 PM
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Joined: Jan 2003
Posts: 9,872
Weddington, N.C.
Streetwize
master
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master
Joined: Jan 2003
Posts: 9,872
Weddington, N.C.
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I wouldn't say they all suck...In your case the center/offset 2 1/2" are pretty restrictive mainly because of the obvious neck-down and the case width being too narrow to allow the over/under flow around the center tube. But the Larger 3" ( ex #17769) Dmax ST of the same design has a taller and wider case and actually has eqaul to or slightly MORE cross sectional/flow area around the top and bottom [roughly 2X(3 1/2 x 1 1/4) or 8.75 sq in vs 7.068 sq in for a 3" pipe) of the center tube than the cross section of the pipe ID itself so the weak point you make is not a serious flow restriction issue. What you have is a compromise of overall case size. I like the large case 3" muffs but not the necked down small case 2 1/2" like your example, there are some very good flowing Super Turbos that give up comparatively little performance vs the ultra-flow compared the considerably lower DB levels. Whwen properly sized the flow of the ST is more limited by the reverse flow than by the internal volume. http://www.dynomax.com/mufflers.php?muffler=superturboI like the ultra-flows but on my 700+hp 12:1 roller motor with a ton of overlap....so for my motors they're simply just too Loud for the area I live. When my car goes by people look for the right reasons...which is worth giving up (maybe)a tenth to me any day. Arguably a better design (in terms of DB reduction) was the Edelbrock stainless muffs that have the UF straight through but the pipe splits into 2 and rejoins inside the case...like 2 y's joined at the top....this gives you more perforated area to reduce the db's. I have a set of the 14" on the 414 Rocky and they're not too loud, seem to be better made and and are noticably quieter than the Ultra-flows. 
Last edited by Streetwize; 11/19/11 01:42 PM.
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Re: Dynomax Super Turbos Suck
[Re: 69Cuda340S]
#1116844
11/19/11 01:55 PM
11/19/11 01:55 PM
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Joined: Jan 2003
Posts: 9,872
Weddington, N.C.
Streetwize
master
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master
Joined: Jan 2003
Posts: 9,872
Weddington, N.C.
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Bill Yeah I guess that's the point I was making....but if you take 2( 3/4" x ~3") that's 4.5 square inches of open flow area which is really only about 10% less than the cross section of a 2 1/2" ID open pipe which is 4.91"....acually it's less than that cause the id of a 2 1/2 is smaller than that. If the case was only 1/2 taller overall (which would give you +1/4" on either side of the tube) the flow area would exceed the open pipe. so that case is properly sized for a 2 `1/4 inlet/outlet, what you have is a marketing/cost compromise. Ironically that muff would probably work better as a 2 1/4 with customer provided 2 1/2" neck downs.  Bill, That's a beautiful car by the way, I think I might have mentioned that before...but just in case 
Last edited by Streetwize; 11/19/11 02:07 PM.
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Re: Dynomax Super Turbos Suck
[Re: Streetwize]
#1116845
11/19/11 03:04 PM
11/19/11 03:04 PM
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Joined: Jun 2003
Posts: 9,225
Charleston
sixpackgut
Drag Week Mod Champion
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Drag Week Mod Champion
Joined: Jun 2003
Posts: 9,225
Charleston
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my challenger went 10.50s at 126, 3800lb, rpm heads, pump gas with those mufflers and full exhaust
Gen 3 power 6.22@110, 9.85@135
Follow @g3hemiswap on instagram
performance only racing, CRT, ultimate converter, superior design concepts, ThumperCarbs
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Re: Dynomax Super Turbos Suck
[Re: Streetwize]
#1116847
11/19/11 03:08 PM
11/19/11 03:08 PM
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Joined: Jan 2003
Posts: 27,421
Balt. Md
383man
Too Many Posts
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Too Many Posts
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Posts: 27,421
Balt. Md
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I agree Bill that you have a very nice Cuda. And I can understand what you mean Wize that even though my pipes go out to the rear bumper with the 3" pipes and Ultra-Flows its a bit louder then I thought but not as loud as some of these cars I see running around the streets. I dont know how some guys get away with it as some cars sound like open headers on the street. Ron
Last edited by 383man; 11/19/11 03:08 PM.
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Re: Dynomax Super Turbos Suck
[Re: Streetwize]
#1116848
11/19/11 03:10 PM
11/19/11 03:10 PM
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Joined: Feb 2007
Posts: 2,578
sweden
1Fast340
master
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master
Joined: Feb 2007
Posts: 2,578
sweden
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Quote:
Bill
Yeah I guess that's the point I was making....but if you take 2( 3/4" x ~3") that's 4.5 square inches of open flow area which is really only about 10% less than the cross section of a 2 1/2" ID open pipe which is 4.91"....acually it's less than that cause the id of a 2 1/2 is smaller than that. If the case was only 1/2 taller overall (which would give you +1/4" on either side of the tube) the flow area would exceed the open pipe. so that case is properly sized for a 2 `1/4 inlet/outlet, what you have is a marketing/cost compromise. Ironically that muff would probably work better as a 2 1/4 with customer provided 2 1/2" neck downs.
Bill, That's a beautiful car by the way, I think I might have mentioned that before...but just in case
just my thoughts on this, those mufflers are a pretty good improvment over any regular turbomufflers design anyway,but obviously not as good as a straight thru glorified glasspack design
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Re: Dynomax Super Turbos Suck
[Re: Streetwize]
#1116850
11/20/11 10:56 AM
11/20/11 10:56 AM
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Joined: Jun 2003
Posts: 3,325
Truckville, the capital of NY
85_Ram_4speed
master
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Truckville, the capital of NY
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Quote:
But the Larger 3" ( ex #17769) Dmax ST of the same design has a taller and wider case and actually has eqaul to or slightly MORE cross sectional/flow area around the top and bottom [roughly 2X(3 1/2 x 1 1/4) or 8.75 sq in vs 7.068 sq in for a 3" pipe) of the center tube than the cross section of the pipe ID itself so the weak point you make is not a serious flow restriction issue.
But the 17769 "Hemi" muffler is only 2.5" inside with 3" hookups on the outside. It never was this way years ago, they used to be true .3" and 2.5" mufflers, but for whatever reason Dynomax has seen fit to reduce the inside diameters in more recent years. Obviously it is not just on the 3" but trickles down to the smaller sizes as proof by the OP's muffler cut up. So case size or not, there is still a internal restriction due to the smaller sized baffles inside.
We were just discussing this on another board and I noted that in the early mid ninties when I worked in a speed shop, they were still the true size, BUT, I remember the later ninties having a foot note in the catalog saying they were reduced diameter. That foot note no longer exists and they just sell them as is----which to me seems like false advertising.
Bottom line is it pays to research before buying nowadays.
Outcast Dodge guy.
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Re: Dynomax Super Turbos Suck
[Re: 85_Ram_4speed]
#1116851
11/20/11 12:18 PM
11/20/11 12:18 PM
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Joined: Jan 2003
Posts: 9,872
Weddington, N.C.
Streetwize
master
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master
Joined: Jan 2003
Posts: 9,872
Weddington, N.C.
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When did they do this?? Mine are 3" all the way and I always check... of course they've been on there for several years. And you are right, if that's the case it is False Advertising and they need to be called out on it. 
Last edited by Streetwize; 11/20/11 12:27 PM.
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Re: Dynomax Super Turbos Suck
[Re: Streetwize]
#1116852
11/20/11 01:24 PM
11/20/11 01:24 PM
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Joined: Jan 2003
Posts: 9,872
Weddington, N.C.
Streetwize
master
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master
Joined: Jan 2003
Posts: 9,872
Weddington, N.C.
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Here's the old Mopar Muscle artical where they back to back the old 3" 20" case Hemi muff against the new ultraflow. You can see a cutaway where the Hemi is clearly 3" all the way through. http://www.moparmusclemagazine.com/techa...ents/index.htmlInterestingly they compared the 20" Hemi Case to a shorter 14" case Ultraflow which really isn't 'apples to apples' in terms of size....backpressure or obviously weight I know the old Dynomax used to be owned by Maremount (which now make the Cherry Bomb Line) but maybe the new owners (who also own Thrush) sold us out and now go a smaller/cheaper route?? That's a real shame
Last edited by Streetwize; 11/20/11 01:34 PM.
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Re: Dynomax Super Turbos Suck
[Re: Streetwize]
#1116853
11/20/11 02:05 PM
11/20/11 02:05 PM
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Joined: Jun 2003
Posts: 3,325
Truckville, the capital of NY
85_Ram_4speed
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master
Joined: Jun 2003
Posts: 3,325
Truckville, the capital of NY
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I am not sure when the change was made but from what I have personally seen, it was around the later mid ninties-late ninties. Of course you also have the senerio where old stock is still on the shelf too. Maybe there are still certian numbers that are the true size, but I have been off of using Dynomax Super Turbo's for so long I just haven't kept up with them. IMO, they are not worth the price for what you'll pay for something much better. Here is the quote from the thread on the other board I go on. Quote:
After a lot of searching last year on mufflers for my car,I chose the large case hemi 3 inch turbos.I read good reviews on them everywhere.I ran a [Email]6.99@102mph[/Email] with these back in the spring and have not had a chance to go back since.Tonight,I took the pipes and mufflers off for the last test and tune of the year at Holly Springs Motorsports tomorrow.After loading the car and going over everything,I took a light and looked up in the muffler and what I saw really pissed me off!Why would anybody manufacture a 3 inch muffler and neck it down to 2.5 inches inside?Dont make sense to me.I gave dang near 100 bucks a piece for these.Anyway,we'll see what it does tomorrow with no mufflers.
Outcast Dodge guy.
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Re: Dynomax Super Turbos Suck
[Re: 85_Ram_4speed]
#1116854
11/20/11 02:28 PM
11/20/11 02:28 PM
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Joined: Feb 2007
Posts: 2,578
sweden
1Fast340
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sweden
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not to stir any crap here but i did some very basic kind of measuring on a #17769 muffler where i work just a few days back and i can tell you for sure that its not 2˝" internaly the measuring was done in a very simple way and not realy all that accurate but i would say about 2 3/4" internaly, unfortionaly that muffler is sold now but when they are on the shelf again i will have another look and do a better measuring that will be within 0,1mm,cant do any destructive check but can check the tubes that can be reached from the outside. have in mind that a internal measurement of 2 3/4" isnt very far from the internal measurement of most 3" aluminized tubing that is measured O.D. a simle formula in metric is 76.2mm od (3")tubing usualy has a wallthicknes of 2mm and there is two walls to count making it a total of 4mm of wall. 76.2-4=72.2 compared to 69.85mm (2 3/4") id measurement inside the muffler 72.2-69.85= 2,35mm 2.35mm of tubing thicknes is not a big loss in my opinion,its not right but its far from as bad as this thread may make it look, i bet there is bigger losses elsewhere in most any prebent exhaust system. ofcourse the loss gets bigger if you use thinner wall tubing. but there is probably bigger losses from the tubing being bent around small radiuses and at great angels. edit sorry for all the metric numbers,im pretty comfortable with the imperial system but its just so much quicker and easier in métric for me to explain it in this case
Last edited by 1Fast340; 11/20/11 02:30 PM.
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Re: Dynomax Super Turbos Suck
[Re: 1Fast340]
#1116855
11/20/11 03:57 PM
11/20/11 03:57 PM
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Joined: Jan 2003
Posts: 9,872
Weddington, N.C.
Streetwize
master
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master
Joined: Jan 2003
Posts: 9,872
Weddington, N.C.
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And all header tube/exhaust/muffler pipe is measured by OD so a 3" nominal pipe is <3" I/D or 3"-2 X the wall thickness. 3" ID would be a bit larger (maybe .15" or so) than 2 3/4" OD which is 70MM and a common European size and very hard to tell visually (at least at a glance) from 2 1/2....right FAST guys  Surely somebody has one on the shelf somewhere.
Last edited by Streetwize; 11/20/11 04:00 PM.
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