how to quiet down 3 inch exhaust

[dusterbd13]

ive got a full TTI 3inch x pipe exhaust on my duster. headers back to rear bumper. im running the kit just the way ot was delivered, with dynomax super turbo mufflers, clamps, their hangars, everything.

im only putting 425 at the wheeels off the bottle, so i know its overkill. but its paid for.

what im trying to do is quiet it down some. its really freaking loud, both inside the car and outside. really takes away some of the driving enjoyment when you have to almost shout at your passenger.

i know the best thing to do would be to sell it and get a 2.5 inch exhaust, but i wont get hardly any of the 600 bucks i spent on it back, and really dont have the 500 to spend on their 2.5.

any ideas of what i can do to get the note down some more? im looking for lower budget solutions here. i was thinking of a pair of canister style cats, resonators, something along those lines.

this is on a 70 duster, and real estate under there is pretty tight, so another pair of fullsize mufflers is not an option. a pair pf more quiet mufflers may be, though.

thanks for any help you can give me.

Michael

[Damn True]

You might look into a resonator downstream of your mufflers.

[badbu68]

Smaller tailpipes will help too.

[Tony_SS]

Inline resonators, both sides. The longest resonators you can find will help out a lot.

[rohrt]

My brother has 3" on his GTO with flowmaster mufflers and its horribly loud with drone. He going to be addressing his issue too this summer.

I would suggest the longest chambered muffler you can fut under the car and the 2.5 tailpipes. I would doubt you would loose much if any performance since your way under 500hp.

[Kenova]

I would try the 2 1/2" tailpipes first. If it is still too loud then some sort of pre-muffler resonator may help. If there is room in the back, you could also try using a resonator in the tailpipe. I've seen glass pack mufflers used as resonators with some success.

Ken

[dontlifttoshift]

Leave the key off.....works everytime.

Man, dynomax super turbo is a pretty quiet muffler I think your only chance is another muffler/resonator somwhere in the system. If there is a straight piece of tailpipe where you could replace it with a glasspack or hushpower i think it help a bunch. In order to quiet it down you need a larger volume muffler...or more mufflers.

Let us know what you find out.

[Zachalanche]

The easiest and probably cheapest way to knock a few decibles off would be to add restriction at the end of the exhaust. if you had an insert that choked the tail pipe off to around a 2 inch diameter I'm guessing you would hear noticble noise reduction. that short area of restriction at the end of the exhuast shouldn't cause too noticeable of a performance loss, and if it did, it could be easily removable so you could just use it when you don't plan on driving hard. I imagine you could fabricate this piece for very cheap, and I also think summit sells something like this.

I would try this before spending a lot more money to undo an expensive exhuast.

[OldMechanik]

Should be able to fit a resonator muffler under the rear/trunk area just before the outlets. 2 1/2 inch tail pipes/resonators would quiet it down.

[TheJDMan]

Check out Speedway Motors they have a number of noise reduction devices used in circle track racing which would work in a 3" pipe.

http://www.speedwaymotors.com/search...-mufflers.html

Their inserts are cheap enough that you could use several of them in combination if needed.

[OLDFLM]

This article may be helpful:

http://www.boyleworks.com/ta400/psp/exhaust.html

I'd suggest 2.5" tails out the back... if that's not enough add some resonators to the tails as others have suggested.

We'll be doing this same exercise to the FreedomBird this fall in fact!

2.5" tails out the back where the springs used to live...



Using these Pypes 4" round mufflers if they'll fit:

http://www.pysales.com/iw_products.m...0S?company=ppe

[Randy67]

Check out Speedway Motors they have a number of noise reduction devices used in circle track racing which would work in a 3" pipe.

http://www.speedwaymotors.com/search...-mufflers.html

Their inserts are cheap enough that you could use several of them in combination if needed.

The auger mufflers work pretty good in tailpipes. I used them with 18" Magnaflows on my El Camino, worked very well. Going with a similar setup on the Camaro.

[billyrb]

if you are running a 3", then restricting it to a 2.5" will quiet it down, but I never like adding a restriction for sound purposes. Inline resonators are great too. Is the noise too loud from inside the car, outside, or both? If you are concerned about inside the car, you might consider adding some dynamat especially near where the mufflers are as it will help a lot with sound abatement

[rustomatic]

You'd probably actually gain power with smaller tailpipes--they help to increase torque. I just tried to talk a friend out of putting a three inch system on his '65 Suburban, as with its stock 350, he'd lose power for sure, especially where he needs it (down low). Otherwise, what everyone else said. Far too much has been spent on exhaust marketing in recent years--see the awesome performance of an 800-pound Harley for illustration.

You could of course quiet the thing down by installing a turbo...

[wmhjr]

You'd probably actually gain power with smaller tailpipes--they help to increase torque. I just tried to talk a friend out of putting a three inch system on his '65 Suburban, as with its stock 350, he'd lose power for sure, especially where he needs it (down low). Otherwise, what everyone else said. Far too much has been spent on exhaust marketing in recent years--see the awesome performance of an 800-pound Harley for illustration.

You could of course quiet the thing down by installing a turbo...

Sorry - have to partially disagree. You won't gain any torque by changing tail pipes. Your exhaust gases have already cooled to the point where it frankly doesn't matter at the tail pipe. You "might" (big emphasis on the might) gain torque in a lower RPM range by reducing exhaust from the collector back. While 800lbs is a bit of an exaggeration for most harleys (most are in the 610-720 range) actually the opposite has been proven using them. It's true that "drag pipes" are performance killers for most bikes, however well designed 2-1 systems factually improve both hp and torque. I've got the dyno sheets to prove that, comparing pipes like the D&D FatCat, the Bassani Road Rage, the (crappy) Thunderheaders, etc. The key isn't the size. It's the design.

I completely agree that 3" is excessive for most people, and that your buddy with the stock 350 would be absolutely nuts to put that on his suburban. I almost went with 2 1/2" tail pipes on my 3" exhaust specifically because with the gases cooling, that "constriction" wouldn't do anything to hurt me. Nor would it help, other than changing the sound.

[dusterbd13]

im truly grateful that this thread has picked up, because im almost caught up enough to start tinkering with the duster again.

couple of notes to ssteer the discussion:
1. a pair of turbos would be VERY fun, but not in the cards.
2. there is no room in the tailpipes for resonators. i had to dimple them to clear the springs, and that was after clearencing the gas tank.
3. the whole car is done with undercoating, 2 layers of dynamat, a layer of 3/4 foil backed jute, and 3/4 regular jute above that. trunk done as well, and insulating material in the back seat.
4. the mufflers are just under the rear seat
5. im not that worried about killing a little power if it makes it that much more enjoyable. killing a lot of power on the other hand.....
6. i dont believe that i can pup anythin before the mufflers either, due to the ground clearance i already dont have.

i do believe that im going to try a set of baffles first, as that seems to be the group consensus on a workable solution. found some threads on homemade verions over on the HAMB, with some parts made by cone engineering. im also really looking at the auger style at speedway. seem to be right up my alley. also found a thread about making baffles for open headers from glasspacks on the hamb, and i think if i could find one for free id try to adapt it for my tailpipes.

the step after that would be 2.5 inch tailpipes, with some resonators in them. go cheapest to most expensive.

i dont want to kill the discussion, as my mind is most definately NOT made up, so please keep up the ideas and discussion.

thanks so far
Michael

[BonzoHansen]

Call Axel Foley


I'd try 2.5" tail pipes first. You already have somewhat quiet mufflers, unless you can put longer ones in.

Are you running an OD trans? I didn't see it mentioned.

[dusterbd13]

this may be showing my ignorance, but whos axle foley?

and no OD yet. planning on doing a five speed as soon as i can after purchasing and installing the AC

and there is just no way to do longer mufflers at my ride height.

[BonzoHansen]

Do OD before AC, it is the #1 best improvement to a muscle car, hands down. How loud will your car be when you drop the cruise RPM 600-1500 RPM? Here is my cruise RPM @ 65 mph in my car
4th 3066
5th 2269
6th 1533


You never saw Beverly Hills cop? D'oh, I'm getting old! Axel Foley=guy putting banana in the tailpipe.

[dusterbd13]

i knew it sounded familiar.....

been a lot of years since ive seen that movie


and in the area i live, i can only drive my car from october to may without dying of heatstroke. and then by the time i get off of work, its too dark. so AC is more important at this point in time so i can enjoy my car throughout the year.

Michael