Flowmaster drone solved.

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JoePole1

A dude in a B body
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So I installed a 2.5 inch dual exhaust using Flowmaster mufflers on my car about 10 years ago and always hated the sound and especially the wicked drone at cruising speeds. At the time I didn't do my homework (should have went with Dynomax for sound and flow) but I have been living with it. I didn't really want to remove the FM's because they are in great shape and welded in the system. I decided to try an H-pipe and WOW did it make a huge difference. I have yet to put the tips on but it sounds more crisp, raspy and deep with no more drone.
I wish I had done this years ago!! The H-pipe kit was cheap and I upgraded to band style clamps. If it matters I am running a mildly cammed LA 360 with hi-po 340 manifolds. I believe the mufflers are FM 40's.

Hope this helps.
 
Nice! I have a TTI 2.5” exhaust with h-pipe and Dynomax mufflers on my road runner and the drone is unbearable at cruising speeds..... gonna try some vibrant resonators before the tips and see if that helps. Harmonics are crazy things.
 
Fish....every set-up is different I guess. I was considering resonators but didn't have the room. I have heard good things about them though. Good luck.
 
Band clamps are the way to go, its all I use now. I weld everything I can but like to keep it so the exhaust can be removed easily. Flowmasters are ok until you start running steep gears and the rpms stay up all the time.
 
Nice! I have a TTI 2.5” exhaust with h-pipe and Dynomax mufflers on my road runner and the drone is unbearable at cruising speeds..... gonna try some vibrant resonators before the tips and see if that helps. Harmonics are crazy things.
On my 68 Barracuda,I have a dual 3" TTI system with 3 in/3 out Dynomaxers, and turn-downs on the end. I have no drone.. with or without the H-pipe. But to be fair I cruise at 65=2240 with the GVod.
To be even more fair, I cruised 4 years with 3.55s and 56=2600, Still no drone but I felt sorry for the HO367 cruising at higher rpms; so since it was only a 15 to 20 minute drive to anywhere I wanted to go, I had the time and 2600 was the engine's happy spot..
I'm not contradicting your experience; like you said;
harmonics are crazy things.
My system is not clamped at all (except the loosely fit suspension clamps) and is held together with soot,lol. To take it apart I just spray it with a penetrating oil and rotate while pulling.
 
Nice! I have a TTI 2.5” exhaust with h-pipe and Dynomax mufflers on my road runner and the drone is unbearable at cruising speeds..... gonna try some vibrant resonators before the tips and see if that helps. Harmonics are crazy things.

I know Dynomax has an older YouTube video out where they mention using one of their glass pack race mufflers as a resonator. Might be worth a try if budget is a concern.
 
Street car with an H-pipe tail pipes and tips .

"Nothing like a loud small block when they are twisted up"

I love H-pipes. X-pipes are not for me. I had a couple and I like the H-pipe. Everyone has there preference. An x=pipe is a little better on the big end. the H-seams to work on the bottom. That is from the seat of my pants.But they are extra large. Just so much more feeling of torque with the h-pipe

The best thing about the h-pipe is the cost. Just weld in a small cross over to equalize the pressure for balance at high RPM's. These are 3 1/2 inch glass packs. We narrowed the factory gas tank to keep the tail pipes and tips on the car.

Hearing this from the drivers seat did not bother me one bit. I wish I could have hooked them up to the speakers





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Joe, glad the H pipe worked for you.

I run 2.5" exhaust with an H-pipe on my 273 Commando, 3:55 and it droned bad with the Flowmasters. Right until I put Dynomax mufflers on it, lol. No more drone!
 
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built 273 commando, hooker headers, e-5 isky solid cam ld4b , stock carb with 2.5" head pipes into dynomax ultra flows Noooooooo drone . dumped before axle. here's a video .

YouTube
 
If you like the sound of the flowmaster 40s, but don't like the drone, I'd recommend Pypes Street Pro muffler. Plus they're stainless and have a lifetime warranty. And no, they don't pay me - lol
 
If you like the sound of the flowmaster 40s, but don't like the drone, I'd recommend Pypes Street Pro muffler. Plus they're stainless and have a lifetime warranty. And no, they don't pay me - lol
I used the the Pypes cat back system with the violator mufflers on my 10 mustang V6 and it had a hell of a bad drone 1800 to 3000 we added in some 15" stainless steel packed Resonators and that helped a lot but I would have used an H pipe instead on an X pipe don't like the sound of the X pipe
 
Joe, glad the H pipe worked for you.

I run 2.5" exhaust with an H-pipe on my 273 Commando, 3:55 and it droned bad with the Flowmasters. Right until I put Dynomax mufflers on it, lol. No more drone!
I put my tips back on and the drone is back. Albeit at a slightly higher RPM. I'm going with Dynomax Turbo's. BTW....Engine Masters did a shootout on muffler sound/TQ/HP testing on under $40 mufflers. They tested no muff, Turbo, Chambered and flow through style. The Dynomax didn't make the price cut but it was still interesting. I believe the Engine had around 450HP.
 
Thanks, I'll check that out. I swapped in a warmed up 5.9 and kept the Dynomax muffles now running through Doug's headers. Super happy the sound out the tail pipes!
 
Does anybody have any experience with the Dynomax Ultra Flow welded mufflers?
 
When I got my Mustang GT it had American Outlaw Flowmasters. The drone was crazy at about 1800. Went to Magnaflows. Also run these on my F150. No Drone. They sound great too. The one I have on the truck is 2 in 2 out with an X cross over built in.
 
I had exhaust drone issues on my 84 Mustang back in the day. 289, c4 and 3.27:1 gears. Was running 40 series Flowmasters. Swapped to 50 series deltaflow Flowmasters and no drone. Was running full 2.5" exhaust, H pipe and tips. Every vehicle is different. Current GT has 40 series and no drone.
 
Yeah. That is key. Every vehicle is different. Car make, SB,BB, Headers, Manifolds, Exh diameter, Exh dump, tips, Cam......
That's what makes it so difficult to compare. I met a guy with a SBM at a car cruise and he was running Flowmaster 50's. Sounded real nice and deep tone.
Said no drone but I wouldn't mind a little quieter. Most everyone running Dynomax turbos loves them and they flow nice so I'm putting a pair on the list. I'll be adding headers so should give them a little more volume. I am going to try to do the changes in stages and record sounds and post on FABO. I believe there is a exh sound thread here somewhere. Yesterday I did my first with the HiPo manifolds, 40's and tips.
 
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Listen, If you want the best sound possible, go with the Flowmaster Delta flow 40 series. They sound way better than the Dynomax mufflers without the drone of the standard 40 series Flowmasters. I have owned all three- Delta Flow sounds unreal even on a slant!
 
Best sound is subjective. I did like the sound of the 50's but I drive my car a lot. Sometimes on longer trips and after dealing with the 40's being pretty rowdy, would like something quieter. The other consideration is performance.
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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?
 
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