How much louder is a dumped exhaust than duals?

tbizzle · #1 08-30-2006, 01:02 PM

I have a Magnaflow Dual system on my 05 Screw 5.4L. I like the sound of the duals but I don't really like the look of the two exhaust pipes exiting. I like the clean look where you can hear the exhaust but cannot see it.

My question is: How much louder is it for the exhaust to be dumped than to run duals out the bac?

My buddy says the sound won't change much (loudness wise) and that the exhaust tip resonates the sound and not the pipes themselves. I think he is FOS but I could be wrong.

I can get it done at the local exhaust shop for around $50.

Let me know what you guys think and if anyone has had duals and then decided to get it dumped.

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BLUE20004X4 · #2 08-30-2006, 02:52 PM

It would be louder, but not much just because the sound waves hit against something (ground) and the bottom of your truck.

Socal858 · #3 08-30-2006, 03:05 PM

you need to be lifted to enjoy the benefits of a dumped muffler. if you are stock height or lowered it will be as quieter than duals out the back. i hate the look of duals too, i would also recommend a single out

DeathMetalTruck · #4 08-30-2006, 03:20 PM

Just curious so I thought I would ask, but is running a dumped muffler under your truck legal? I live in CT and not sure if they have laws that state that you need to run exhaust out from under your truck or not? I don't plan on doing it, but I was just wondering if anyone knew or not seeing as I know people do that.

torturekilla · #5 08-30-2006, 05:30 PM

my exhaust is gonna be dumped under the truck i hate the look of dual pipes or any pipes hanging out the rear ..... ima have them tucked in under the truck........jbas/dual 40 series....next step..

Patman03SprCrw · #6 08-30-2006, 06:00 PM

Quote:

Originally Posted by BLUE20004X4

It would be louder, but not much just because the sound waves hit against something (ground) and the bottom of your truck.

Yes and no. Mine actually got louder when i lowered 2/3 B.c it hits the ground sooner, it projects the sound outward sooner. Lifted trucks you can hear it a little louder sometimes b.c the truck is working harder to move bigger tires, and b.c there is nothing for it to hit.

At stock ride height, the dumped will sound a little louder inside the truck, and the tone shouldnt change. And it will not resonate, with anoying vibration in the truck as much. You should be able to get a shop to do it for much cheaper the 50 bucks. If i were you, i would cut off just infront of the axle at home. List the pipes/tips online for like 40-50 bucks, and then the shop should charge you like 20-30 at the most to bend the pipe and weld it on.

On trucks it is legal, to have it dumped at any point. If you see a large box truck you will notice the pipe is dumped like at the back of the cab.
Cars it is legal to have the tips dumped before the rear of the car, after the axle, assuming there is a trunk, and not "cabin" above where you are dumping it. Like on a camaro that has a rear hatch that connects to the cabin, it is not legal to dump the exuast. But say a taurus, you can dump it anywhere after the rear axle, before the back of the car.

DISCLAIMER: This is my personal understanding of Tx laws/ inspection rules, and may vary from state to state, so check with your local authorities.
-Patrick

Impact9 · #7 08-30-2006, 06:55 PM

Sorry being a bit off course here.

What exactly is "dumping"? Is that just where you cut the tail pipe where ever you want after the muffler? I got a saws all here ready to go!

Socal858 · #8 08-30-2006, 07:18 PM

exhaust not louder on lifted trucks because "they are struggling to move their tires," for a fact most 20s weigh as 35/12.5R16 wheel packages; but that is a pretty funny statement to hear.

the height amplifies the sound and deepens your tone because your whole bed becomes a large exhaust tip. the frequency (waves per second of time) between the sound wave contacting the ground and bottom of the truck decreases with height (fewer waves per second bc distance), hence deepening the sound.

with a stock height truck, your observation of tone depends on your previous setup. if you ran the muffler with pipes capped wtih large tips, you wont be anywhere as deep. the existence of resonation has nothing to do with how much pipe you have, it is a property of the muffler. some mufflers will resonate more than others, but yes all mufflers will be louder in cab being dumped , and you will notice more resonation depending on the type o fmuffler you have chosen

Patman03SprCrw · #9 08-31-2006, 02:20 AM

Thats my exuast dumped, basically means no tips, and the pipe is pointing to the ground. I would agree that a big rim weighs alot, but i dont have big rims

I have factory.... So i dont see how that is relevent in my case.
i do also agree that a lifted truck can be louder, but that may just have to do with the pipe/muffler being closer to your ear, meaning closer to you if you are riding in another car, or standing on the street.
I can understand what you are saying about the harmonics of the truck, but its usually the frame that creates the sound not the bed. But i would think that if anypart of the truck makes harmonics, it would be more significant when lowered b.c the sound would be bouncing up and down under the truck, and not just passing by.
Im not an expert on this subject, i just know that when i lowered my truck, my exuast got louder. Thats all my point is.

And weight wasnt my point on the tires quote, i was saying larger diameter wheels/tires, and effectively lowering the gear ratio, loosing torque, and thus has to work harder to get moving....
-Patrick

Socal858 · #10 08-31-2006, 02:31 AM

i understand what you are saying about the frame rails , etc; that makes sense theres a dead spot in height where you neither get body resonation or height resonation; just a theory at the moment from combining what we both observe. the rim thing wasnt targeted at you, i was assuming you were going to do a lifted / lowered comparison. you are pretty cool to dialog with, you dont go into tampon mode like most people so id definitely beer you

i still find the lifted truck thing pretty assinine, power has nothing to do with it, height will affect the sound simply because its height; yeah there are plenty of underpowered lifted trucks (id say 90% of them cant get out of their own ways frankly) but im speaking about amount of noise per RPM, or hell, even revving at a stop

Patman03SprCrw · #11 08-31-2006, 02:20 PM

Quote:

Originally Posted by Socal858

you are pretty cool to dialog with, you dont go into tampon mode like most people so id definitely beer you

heh

No really tho i can trust your word about lifting and getting louder, it sounds logical, but i think you just didnt quite have the source of the harmonics down. Anyways tho. I was just making a point about the rims b.c i wasnt sure if you were dirrecting that at me or not.
thanks for the kind words. Same in return to you.
-Patrick

Redf150-2wd · #12 09-07-2006, 06:52 AM

i had the flowmaster 40 series SIDO and had it dumped after getting my lift b/c the piping was rubbing on my shocks

it was actually quieter after i dumped them, but if ur looking for something reaaaaaaaally loud, go with an exhaust cutout and keep either a stock tip or w/e setup you had before.
its not exactly legal but it sure is loud and if u keep the tips on there its harder (visually) to tell that you have an exhaust cutout

as for legality on dumping ur exhaust....i dont believe that theres laws on if ur pipes have to run out from the truck or not. you still have a muffler and it will pass inspection. But you never know up north, they seem to have some ridiculous laws about trucks

next time u see a cop at the local doughnut store

, just pull over and ask him

gixxerjay · #13 09-11-2006, 08:27 PM

Dumped will be deaper sounding, but not any louder. Used to do this on my old mustangs back in the day.

Derk · #14 09-12-2006, 08:47 PM

Yeah when I dumped my magnaflows on my old mach 1 it didn't make it any louder, but the sound became deeper. Like I turned up the bass a few notches.

01Screw17 · #15 04-22-2009, 05:09 PM

I know im reigniting an old thread, but I just cut my exhaust off before the rear axle and dumped it, and it sounds horrible. It is way quiter than before when I had tailpipes with tips at 45 degree angles. I'm tring to figure out right now how to get my sound back, because right now it is way quite and way less deep sounding than before. I dont know if it has to with may glasspacks being so close to my dumps or what.