Flowmaster drone solved.

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Depends on size, outlet and inlet configuration, and what car and engine they are on. They are louder than the Wrapped UltraFlows and have less packing internally than the other packed Dynomax UltraFlows. I have more data and I'll see if i can find anything of value. You need any mufflers?

The one I have has a 14" body, offset inlet, center outlet and it;s going on a 2.5" single system on my slant six Valiant. Cruise RPM is probably 2500-3000.
 
RRR, the Ones we tested for the data in the chart (17513) are 20" long ones and they are quieter for sure than the shorter 14" case ones. And, they have less tendency to drone as well because of this larger size.
 
it seams like stuff is all over the place some get drone some don't I'm all about sound and tone NO drone not extremely loud (I've had my fill of too loud with my harley) my setup will be I'm putting in a 360 auto TTI shorty headers 2 1/2" all the way back tips and lost on mufflers Flowmaster Delta flow 40's, dynomax ultra flow or super turbo (heard a couple people say super turbo's drone bad) or pypes street pro
 
The one I have has a 14" body, offset inlet, center outlet and it;s going on a 2.5" single system on my slant six Valiant. Cruise RPM is probably 2500-3000.

It'll be little noisy but not bad on the slant six.
 
it seams like stuff is all over the place some get drone some don't I'm all about sound and tone NO drone not extremely loud (I've had my fill of too loud with my harley) my setup will be I'm putting in a 360 auto TTI shorty headers 2 1/2" all the way back tips and lost on mufflers Flowmaster Delta flow 40's, dynomax ultra flow or super turbo (heard a couple people say super turbo's drone bad) or pypes street pro

Bryan use the 17748 longer case Dynomax 2.5" versions and they will have virtually no drone and sound great and are quiet and flow well. You have to be creative to get them on an A body but they will go.
 
It'll be little noisy but not bad on the slant six.

What I'm after is flow. I have the exhaust manifold outlet enlarged to 2 1/4 all the way in. I am hoping with the TTI 2.5" exhaust and that Ultra Flo muffler, it'll help it out a little more. I'm hoping it won't be aggravating.
 
What I'm after is flow. I have the exhaust manifold outlet enlarged to 2 1/4 all the way in. I am hoping with the TTI 2.5" exhaust and that Ultra Flo muffler, it'll help it out a little more. I'm hoping it won't be aggravating.
It should be fine!
 
Im using long tubes, 2 1/2" X pipe, 14" Pypes Race Pro mufflers like a Magna Flow, stainless straight thru with packing, tailpipes out the back with tips. I had a wicked drone at cruise. I tried chambered, no better. I finally welded into the tail pipes Helmholtz tuneable resonators. No drone what so ever and the idle is quieter also, until you stand on it and it gets heard. They do an amazing job.

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I keep going between a Ultra Flow stainless in 2.5", or a 3" Super Turbo for the system in my Challenger. I don't think I have enough room for a 20" muffler, but since the E bodies did have factory resonator I could always run a Race Bullet, or second round Ultra Flow if it is too loud.
 
Use 2 different mufflers, and an H-pipe or X-pipe on dual exhaust. Even slight muffler differences (such as case length) can reduce/eliminate drone. Original Pontiac GTOs had 2 different mufflers. Also, some late Mustangs use this as an OEM drone-reducer.
 
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Bryan use the 17748 longer case Dynomax 2.5" versions and they will have virtually no drone and sound great and are quiet and flow well. You have to be creative to get them on an A body but they will go.
Would they go in the stock location? Where ever that is before or after the rear end?
 
What i find interesting on that chart is the dynomax's, with or without the x-pipe. Two were quieter, one was louder, one quieter at idle, louder at cruise, quieter at full throttle. Just proves that nobody can predict exactly what will happen with an exhaust system. It depends so much on so many different variables!
 
it seams like stuff is all over the place some get drone some don't I'm all about sound and tone NO drone not extremely loud (I've had my fill of too loud with my harley) my setup will be I'm putting in a 360 auto TTI shorty headers 2 1/2" all the way back tips and lost on mufflers Flowmaster Delta flow 40's, dynomax ultra flow or super turbo (heard a couple people say super turbo's drone bad) or pypes street pro
You have mentioned all three of the common muffler types, chamber type, straight thru, and triple pass. (Chambered have a rep for droning). My suggestion is to find a car with the sound you like, cause all three sound different, and use what you like. My answer for a good flowing, quiet system, is get the right size pipe, and the biggest,longest muffler you can fit under the car!
 
Bryan the 17748 is a 20" body muffler and stock uses 18" ones. I shortened the inlet bushing 1" and then welded three bolt flanges to the outlet bushing that had also been shortened. i also welded flanges to the tailpipes so instead of sliding in, they bolt on. They all fit fine and sound great.
I love the Helmholts tunable resonator pipes listed above too!
 
Voetom, I'd like your opinion. I have a 1970 Duster 340 with 833 trans. It currently has OEM manifold,
2 1/2" H-pipe exhaust with FlowMaster 40's and piped to the tips. I like the sound but do have drone at cruising speed. I am redoing exhaust using TTI long pipe headers, 2 1/2" X-pipe exhaust to the tips. Would like your opinion on mufflers. Engine Masters showed that X-pipe exhaust quiets the sound so still looking for that muscle car sound out of my system. Street car use mainly. Your thoughts? Thanks.
 
I am the OP and I should have updated this thread. I run 340 hi-po manifolds 2 1/2" exh and H pipe with tips on my B body. I wound up removing the flowmaster 40's and going to dynomax turbos for sound and better flow. Drone solved. Only issue now is that it was too quiet for my taste. Well last week I installed Flowtech ceramic coated headers that I bought at a swap meet years ago. Wow. Huge difference. Sounds proper now and added seat of the pants torque. No drone. Its a nice mellow rumble but barks when you get into it. It would sound even better with a nice cam. I highly recommended but if you prefer the something louder the Ultraflows. I always heard that the 340 manifolds flowed as good as headers but I don't believe that to be true.
 
I’m upgrading to full 3” TTI exhaust and was considering flowmaster 40’s until I read this… what do you guys suggest for a good sounding muffler?
 
I’m upgrading to full 3” TTI exhaust and was considering flowmaster 40’s until I read this… what do you guys suggest for a good sounding muffler?

If you prefer the sound of a chambered muffler exhaust, look into Pypes Street Pros. I replaced a couple flowmaster 40's with them and couldn't be happier.
 
You have to use the Delta Flow 40 Series Flowmasters. Not the regular 40 Series. Delta Flow's sounds Fantastic and you don't get the Drone
 
I'm running the Black Widow Race Venom's with a cobbled together system. Longtubes are on my radar but I do like the sound of these mufflers.


 


My 71 has hooker supercomp long tube headers, the summit brand 2.5” exhaust, and thrush mufflers. First off the sound is very muddy to me. The headers hang down far too long and run into the steering linkage pretty bad. Also, the person who installed them before I owned the car welded it up like crap and it interferes with the leaf spring on one side. Planning on TTI 1-7/8 headers, TTI 3” H pipe, TTI tips, and still debating on mufflers! The pypes street pros sounded great in all the videos I watched.
 
I'm a huge fan of the Flowtech Terminators. They are a chambered muffler but I didn't get drone with them like Flowmasters. They sound great (IMO) and were not loud unless you mashed the pedal.
 
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