Big block exhaust is still loud

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clementine

clementine

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Helloooooooo FABO!

I must be getting old.

1967 barracuda fastback
383
TTI headers
3" X pipe over axle and out the back.
20" Dynomax (no chamber)

So recently i switched out the mufflers as the 14" summit mufflers were not cutting it. Granted i have no interior in the car, and I'm running it in the garage, outside the car is still quite loud.

What is the solution short of going to a 2 1/2" pipe and choking the engine?

will a inline cherry bomb or "resonator" reduce the noise? Or.... it's just the way the big block is going to sound. Ive had big blocks before and yes, they were loud..... but i didn't care.... now, i kind of care.

I like being able to converse in the car and i think with enough dynamat and carpeting i can keep the heat/ noise out, but is there anything i can do for my fellow man? Also not looking to pick a fight at every light.

I might be dreaming.....guy has got to have goals right?

Thank you FABO!
 
I have a fresh 9:1 Ford 400 in my 75 F250, Gladys. It has 1 7/8 primary tube, 3" collector headers with 3" exhaust (with no cross over) to the rear axle with turn downs. I have the Summit welded, Flowmaster knockoffs on it. I was kinda worried it would be too loud, but much to my surprise, it's surprisingly quiet. I don't think there's any way I'd go back down to a 2 1/2" pipe. I can get a video if you like.
 
Imo, the secret to a quiet good flowing exhaust, is getting the proper size tubing, and then getting the biggest longest 3-pass muffler with that size tubing that will fit under the car.
In your case, since you already changed the mufflers without using the biggest that would fit, I would add the longest 3" glasspack I could find that will fit in the tailpipe alongside the gas tank.
Edit: did you use the triple pass muffler, or the straight thru?
 
without any interior it will be absolutely thunderous, and when you add that to being in a garage the echo can be darn near unbearable.

if you haven't run the car in quite some time, you may be sensitive to how loud it seems; even more so in a closed environment.

but you're spot on, some dynamat and foil back jute mat should keep the interior reasonable.
 
You need to take the engine down and lower the compression...... Five to one should do it ............ lol.
No Just kidding.
on my 367@ 11/1 the dual 3s are really loud at full-song. I installed the Longest 3-pass dynomax muffs offered in 1999 which quieted it right down. But to be even quieter I installed a GV od and 3.55s, for 65mph =2240rpm.
This set-up came to me from TTI, with an H-pipe. To install the GVod, I had to cut that H out. Afterwards, I notice right off that the engine had lost a very significant amount of off-idle torque, AND the exhaust system was quite a bit louder.
I solved the torque loss by installing a 3.09 low gear trans versus the 2.66 that was in it.
I got used to the louder exhaust around town. If I have company in the car, I just short-shift, or stay off the gas. Those long Dynomaxers are actually pretty good; they've been on the car since 1999.
 
33IMP said:
triple pass muffler, or the straight thru?
Click to expand...
Straight thru....

What's the longest that will fit? I am barely off the tirn from the X pipe before getting into the muffler. Maybe another 1"?

So a 3 pass is a chambered design?

#learnin
 
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clementine said:
Straight thru....

What's the longest that will fit? I am barely off the tirn from the X pipe before getting into the muffler. Maybe another 1"?

So a 3 pass is a chambered design?

#learnin
Click to expand...
Sorry, forgot I was on the A side. My b-body has a 5"x12"x22"body muffler (two actually) that probably won't fit under an A body. My other big block car has a 28" body straight thru magnaflow. Pretty quiet.
There are basically three types of muffler:
Triple pass. 95% of stock style mufflers, exhaust passes through the muffler in an "s" shape (turbo's)
Straightthru: glass packs, you can see thru em. (Cherry bombs) Louder than triple pass.
Chambered (Flowmaster and copies, hooker aero) distinct sound, can be quiet or loud, depending on internal baffles and number of chambers. Typically can have a nasty drone.
 
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Not that it's the best solution but 2.5" duals would be far from choking your 383 unless it's 500+ HP.

Going to 2.5" tailpipes and adding resonators there would quiet it down a lot.

Next best would just be adding 3" resonators in the tailpipes.

Triple-pass mufflers are significantly quieter than straight-through though as well. I've run Dynomax Super Turbos and they're too quiet for my tastes unless it's a real big rowdy engine. But then I like loud engines lol, as long as there's no bad drone inside the car.
 
I was running dynomax super turbos with 2.5 x pipe with the 340 stroker.
I found it very loud. Hard to converse and beat the crap out of you on long drives. Made the car somewhat unbearable. Everyone loved the sound.

Doing the big block swap now and keeping the 2.5 x pipe for now but I changed the mufflers to walker quiet flow 21856. We will see what the sound is like in a couple of weeks. I also changed the tranny to t56 and a lot less camshaft. So we will see if I miss the sound of power.
 
Flow master makes one that quiets it down without the power loss or so they claim
 
I can barely hear this 440 run. Stock manifolds, 2.5" head pipes into an X and 3" tail pipes. Wouldn't have been the way I did it, but the way I bought it and it's damn near silent until you get on the loud pedal!
1964dodge440cleanup2023pta 054.jpg
 
I checked the box and I think these are them.....perfect English.

Dynomax Performance 17233 Dynomax Ultra Flo Welded Mufflers | Summit Racing

I have the pipe to run out the back, but for giggles Ill check to see what the cost is to reduce to 2.5 from the axle back.

Maybe need to just get it out of the shop to hear it outside like a previous member noted.
Thanks fellas!!
 
dukeboy_318 said:
I doubt the reduction in noise will be much.
Click to expand...
The 3" kit I have now needs some tweaks to be heading out the back the way I want it so Ill need to visit an exhaust shop for that. Ill finish it out and if its too loud still, I can easily cut in some resonators, or glasspacks of some sort......I still cant see the difference between the two. A resonator looks like a short glasspack to me.
 
clementine said:
I checked the box and I think these are them.....perfect English.

Dynomax Performance 17233 Dynomax Ultra Flo Welded Mufflers | Summit Racing

I have the pipe to run out the back, but for giggles Ill check to see what the cost is to reduce to 2.5 from the axle back.

Maybe need to just get it out of the shop to hear it outside like a previous member noted.
Thanks fellas!!
Click to expand...

Ultra Flos are definitely louder than Super Turbos, I'm surprised @dodgedifferent2 found the Turbos loud but I guess it goes to show a LOT of the sound depends on the engine making it. Maybe he had the exhaust rubbing the chassis/body somewhere or the hangers weren't all rubber isolated properly? That can cause tons of drone and interior noise that'll drive you crazy, just a thought. But then I've never heard in person a set of Turbos on a proper high-output big-displacement engine.

I have Ultra Flos on my '72 D200 pickup and they're hardly louder than whatever mufflers were on there before, I'd assume stock replacements. That truck has a 360 with long tube headers but stock 2-barrel cam, I drove it a few times before getting the rest of the exhaust hooked up and it was very quiet at idle, could hardly tell it had open headers until it was under load.

I had a 1993 Jeep Cherokee XJ with the 4.0L inline-6 that was my daily driver for about 10 years. I first put a Classic Chambered PowerStick muffler like I have on my Duster and it was loud to the point of being borderline obnoxious. Some years later I put a Super Turbo on it and it was way too quiet, almost like a factory muffler. Last 5 years or so I had it I ran an Ultra Flo and it was a perfect balance, you could hear the engine at idle and when heavy on the throttle but at cruise it was very mellow. Again though that was essentially a stock "truck" engine, very mild compared to any Mopar V8 with a decent camshaft.

@clementine I doubt there will be much noticeable volume reduction just going to 2.5" tailpipes with no other changes. You are correct though, resonators are pretty much just small glasspacks. They are interchangeable for all intents and purposes.
 
Taking the vehicle out of the shop will not change the level of noise at (or close to) the source, as the noise is the noise.
What will change by going outside is the perceived level of sound in the car or at any distance from it. IF that change is enough for your comfort or expectations is entirely subjective and up to you to decide. I wouldn't go through the expense of making more changes until you (1) listen to it outside the shop, from inside the car and standing nearby. (2) listen to it as you are driving it. (3) listen to it as a helper drives past you driving normally. and (4) Drives past you while getting on it.
Then make any changes you feel needed. Maybe you only need to stay out of the pedal when driving through neighborhoods.

Flat panels (walls) reflect sound. Flat parallel surfaces (2 side walls) bounce sound back & forth between them. A square cube of a room is the worst, a rectangle not far behind. The size of those walls will determine which frequencies are affected more than others. Corners reinforce (amplify) lower frequencies (single corners, wall to floor, wall to ceiling, wall to wall,) and even more so at double corners, (wall-wall-floor or wall-wall-ceiling)
 
I've never heard this before, my big block exhaust is still loud, what language is that???
I love a fast car that is pretty quiet though
My friend who is almost 60 told me 45 I'm old for liking that.
I'm going to try to quiet mine down. Man I love the sound of the terminator mufflers I had on my charger back in the 1990s
 
clementine said:
Helloooooooo FABO!

I must be getting old.

1967 barracuda fastback
383
TTI headers
3" X pipe over axle and out the back.


What is the solution short of going to a 2 1/2" pipe and choking the engine?


Thank you FABO!
Click to expand...
It seems to me that the 3" setup may be overkill for a 383. I have a 3" system in my 440/495 in my Charger. I ran 2 1/2" exhaust for years with the 440/493.
 
The Welded Ultraflows do not have as much ceramic/glass fiber inside as the polished ones. They are more rumbly and will roar more. Walker Dynomax used to have a great 3" one; let me look.
 
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