hi

i am going to change my pypes brand street muffler to their race muffler , quieter than their street muffler !

look it up !

511 cu hemi

I never had a set of them , that is very interesting .

Accurate has sound clips mufflers

Super Turbo with a center exit. The exhaust has to flow around the exit pipe. Not my picture. This topic has come up before and I saved the picture.

I'm running those mufflers on my Challenger.

TTI 3" exhaust, 402ci Magnum, 9.8:1CR

https://youtu.be/7KEn2UltCJc

I've used 17748, the 2.5" version on my 2005 5.7 Hemi Magnum.

*It's important to differentiate between the short case one that usually drones, and the long 20" case model that usually doesn't.

The car had no cats and an H pipe, so very similar to an older car in that regard.

I loved them, they were just right for a good, throaty sounding driver that was never annoying.
Long distance drives, 3-5 hours, no problem at all.

They do not flow well. The car felt faster with 2 chamber flowmasters, and even those don't flow well.

But they do keep the car pretty quiet and sounding good.

I feel they are a little too quiet for an occasional short distance Hellraiser kind of a car which is why they make the race bullets and the ultra flo.

That was my line of thinking , I was going to try to fit the 20" case muffler in place of the short case to see if it was the case.

Only time I've experienced drone in my cars was:
1. 3" system with Flowmaster 40s with before-axle turndowns - 2.5" tailpipes cured it.
2. '64 Savoy wagon 3" system with almost anything - tried 3 different sets of mufflers to get the right sound - and tailpipes cured that.
Both had quite "healthy" RBs that seemed to merit big pipe.
I think the interior volume on the wagon - basically a big drum - was a large part f the problem.

As for case length, it seems to me that the more volume in the case, the less restrictive it is.
But I have no date to prove/disprove that.

I have this video,
1967 GTX , basically stock 440

It has just a tad more rumble than my car presently does. I think I like it


https://youtu.be/lnO333xn7zY

Just took this.
I just put a fresh set of plugs in. So ignore the smoke

https://youtu.be/7PfxZ13QXPE?feature=shared

Well, I used to work for Dynomax & I can assure you, a 2.5" version of the Super Turbo flows better than a 2.5" or 3" 2 chamber, 3 chamber, or Delta flow Flowmaster. The 3" Flowmaster versions had flow rates of around 350 scfm, while the 2.5" Dynomax Super Turbos have flow rates of around 410-420 scfm. Comparative OE mufflers have flow rates of usually under 200 scfm. I remember buying a pair of 16" bodied Chrysler "Hemi" mufflers from Mitchell Motors back in the early 80's - to replace the 20" bodied originals on my old '71 Hemi Charger. The mufflers from Mitchell flowed like CRAP - I could immediately tell they were restrictive. Back then I didn't know crap about exhaust. I should have installed a set of Walker Red Line Z mufflers, which evolved into the Super Turbos.

The big differences internally between a Dynomax Super Turbo & an OE muffler are two things: the size of the internal perf tubes, & the Super Turbos have flow directors (bank turns) at each end, & OE's do not, and most other performance mufflers won't either. If you buy a 2.5" in/out Super Turbo, it will have 2.5" flow tubes inside. An OE type muffler with 2.5" inlet/outlet, will usually have 2" dia internals. A CHEAP, crappy turbo muffler (like the Thrush California Boss Turbos) have 2 flow tubes internally & NO packing, plus the flow tubes are smaller diameter. Super Turbos have a fiberglass mat that wraps around the center section of the muffler (you can see it in the photo someone posted), but this mat breaks down in about a year or two, & the mufflers will get louder - especially the 14" ones. Some oval mufflers have two flow tubes, some have 3. The Super Turbos are GOOD turbo mufflers. The Dynomax Ultra-Flow mufflers are straight-through, & they do not "tune" the sound like Super Turbos do, so they sound different than each other. From a flow standpoint, the scfm of a 2.5" 14/20" Super Turbo offset/center is around 410, and a straight-through Ultra Flow is around 1100. There is a HUGE difference in flow, but do you really need the extra flow of the Ultra Flow? Only a few dyno runs could tell you. Bob Karakashian & many of the other guys running in the Pure Stock Drags are using the Dynomax Ultra Flows. Those WAAAAAY outflow flowmasters & all other non straight-through oval mufflers. The stainless Ultra Flows with the stock-style spun-locked heads, flow the same as the Dynomax race series welded construction mufflers - also now called Ultra Flows. The welded series are offered in bigger flowpath & bigger in/out than the stainless ones, so there is more variety. On a closing note, I don't know what the internals are like in the Accurate mufflers, & I don't know who is building them for them - I doubt they have the equipment to build them & especially fab the spun-locked heads. If they do, then that's impressive.

There are quite a few mufflers currently in the Dynomax & Thrush line that I suggested & partially designed. There were also ones that I tried to get them to bring to market, but was unsuccessful. One was reverse flow Super Turbos in 2.25" & 2.5" versions for AAR's & T/A's - the standard oval size but 20" long. *They currently offer these reverse flow mufflers, but they are only 14" long bodies - not long enough. Those were referred to as "fabricator" mufflers. I have been building my own chambered exhaust mufflers & mufflers for AC Cobras since 2002.

Do the 6" round ultra flow sound or perform different than the more conventional oval shaped ultra flows? They might fit on each side of an ebody gas tank.

Found a pic of what I am considering.

A good pair of headphones is the best way to listen to this Dynomax "Sound of Dynomax" link

https://www.dynomax.com/sounds-of-dynomax/?muffler=ultra-flo-ss-polished-muffler

SOUND OF DYNOMAX LINK CLICK

Mike, Listening to them . along with the 67 GTX video I posted earlier today. Im no closer to picking a muffler than ever.

Bill, honestly I think you would like the Ultra Flo's SS or welded. Nice muscle car throaty sound at idle, quiet and no resonance or buzzy sound at cruising speeds and then a great sound during acceleration or kickdown or down shift acceleration. I forgot that I do have a brand-new set of Ultra Flo SS also still in the boxes that I bought to replace those Flowmaster 40's currently still on the GTX.

Is it possible to pair a resonator with the super turbos that will tame it down, kill the drone and maybe some overall sound, without knee capping performance?

I have some stupid thrush ones that my exhaust guy is fairly sure are flowmaster knock offs. I don’t like these and one is starting to do the popcorn thing from internal rust. I’d love to add an h or x pipe, new mufflers, and add factory exhaust tips behind my stock 440. I had been leaning towards getting the accurate stuff, maybe the hemi ones, and some sort of resonator, their stock ones or otherwise.

I just don’t know.

As I mentioned earlier, putting any cheap glass packs (now they're called bullets) in the tail pipes behind the axle will pretty much kill the drone. And they won't 'kill' the flow.

Everything I've found says the 17747 Dynomax is a 2.25 tube muffler. Is this truly what you are after because most replies in this thread are speaking to 2.5 or 3 inch diameters?

Some things people in here have stated and I think most of us would agree to - 2.5 and 3 inch tailpipes will increase the sound. Straighter thru mufflers will increase the sound. Higher compression ratios will increase the sound. More cubic inches will increase the sound.

Since your engine is built, you can't alter the displacement or comp ratio. That leaves exhaust system as the only mods. A change to 3" tail pipes could give you the extra sound you want. If you don't want to change your pipes, then put a more straight through or free flowing muffler on it. Super Turbo and Ultra flow both achieve that. IMO ,the reproduction system was designed to match factory specs which wanted to meet a certain NVH requirement that the factory set at the time. Anything that flows better will be louder, only question is how much so. Despite what the sound clips are putting out there, I'd venture the extra turns inside a Super Turbo will be quieter than the straight through Ultra Flow. If you are afraid of it being too quiet, you can go Ultra Flow. If its too loud, then add resonators.

These places both have big block sound clips on similar cars that might be more accurate than the Dynomax site and might be able to help you find what you want:
https://www.gardnerexhaust.com/sound-clips/
https://www.accurateltd.com/B-Body-Mufflers-_p_192.html

Correct the 2.25 is what I need / want. My exhaust is in excellent shape so In not changing pipes . I just want a little more rumble.

Ive looked at the Accurate hemi HP mufflers and their standard hemi mufflers . But at almost $500 for a pair.
Im looking for less expensive alternatives

Keeping it 100% OE stock appearing isnt top of my priority list

Like I mentioned earlier.

This is my 383 car and has the Dynomax Super Turbos only in a 2.5inch version and If I thought my hemi car would be similar to or maybe even a tad quieter. I would pull the trigger on the 2.25inch version and move forward

https://www.youtube.com/watch?v=H1eP_QMFfMU

Whats interesting is this 67 440 powered GTX and my 66 383 powered Satellite have the exact same exhaust system on them . 2.5inch TTI and Dynomax 17748 mufflers all thru the OE stock exhaust manifolds on both car
The only difference is the tips. And to my ear they have a huge difference in sound

https://youtu.be/lnO333xn7zY