how to quiet down 3 inch exhaust

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

Add a 2.5" sandwich plate where the flange bolts up, it will restrict the flow but will reduce noise also,

Room for a couple of short glasspacks in the tailpipes?

turbos, 2 or 4 of them.

~Alex

Where is the noise coming in? Where does it originate?

Streetwiseguy wrote: Room for a couple of short glasspacks in the tailpipes?

+1, glasspacks were litterally the first thing that came to mind

MrJoshua wrote: Where is the noise coming in? Where does it originate?

I am gonna take a wild stab and say the combustion process

Dunno if a 2.5" exhaust alone would really be that much quieter. You need more mufflers, either larger ones to replace what you have, or additional glasspacks/resonators.

The 2.5" exhaust I have on my LS1 944 is damn loud too.

is the 'turbo' in the muffler name denote a turbo application or just their name for the muffler? if its for a turbo its going to be a LOT louder on a non turbo'd car and see if there's an NA version. if its just a name then i'd say just needs more muffler/resonator in the system.

resonator

which Super Turbo mufflers do you have? i'm thinking that a 3" dual exhaust kit is going to come with some shorter body mufflers for less restriction. you might be able to get some longer mufflers that will quiet things down a bit, and add some 2.5" glasspack mufflers back by the bumper. the smaller mufflers way back there won't restrict the flow too much, and the X pipe makes the exhaust appear "bigger" to each cylinder, anyways, since it all gets blended together at the X.

Curl the end of the tailpipe in or put a cheapie chrome tip on it that curls in. Seriously, most of the noise is traveling along the wall of the pipe. Block it and it bounces back up the pipe to the engine.

ditchdigger wrote:

MrJoshua wrote: Where is the noise coming in? Where does it originate?

I am gonna take a wild stab and say the combustion process

Jerk!

To rephrase: Does the excessive noise all come out the end of the tailpipe or does a lot of it come through the header walls, through the resonator walls, from areas of rapid size transition, through the x-pipe walls, etc...? Thinner walled piping of aftermarket systems can cause noise problems from areas other than just the end of the pipe. Sometimes adding a resonator under the passenger compartment can actually cause more noise in the car while quieting the outside. Another issue can be the ends of the pipes. Do they terminate under the car and cause the noise to drum off of the floor? The noise through pipe walls can be quieted with wrap or kept from coming through the firewall or floor with sound deadening material on the car. If the problem is truly the lack of sufficient muffling, there are many options to improve that including the resonators mentioned by others.

I'm sure others will disagree but in my experience, nothing but baffling does any real jack poop to reduce noise. When I tried to get my car to meet the noise limits of some tracks, I tried Corsa resonance noise canceling, resonators, glass packs, a huge magnaflow straight-through. I got it just under with the Corsa and magnaflow but it was still damn loud. The car was quieter when I first fired it up with just the stock midpipe to direct exhaust gases - the cats alone did more to muffle the noise than any of that crap, because it put something directly in the path of the gas.

So in my opinion, if you're serious about shutting it up, you need baffled muffler. Everything else might just take some edge off the sound, or change its quality, but not db measure.

te pipes terminate at the rear of the car. mufflers are where most of the noise origonates from, and they are located under the back seat and rear footwell area.

the super turbos from dunomax is just a name, and supposedly theyre quietest performance muffler.

there is NO room for a glasspack back there. i had do dimple my gas tank just to get the pipes in. would race b ullet style mufflers do the same thing?

i like the idea of the "restrictor plate" may have to make some and try them.

anyone have any experience with walker soundfx mufflers? i can get a pair of those pretty cheap.

I'm running the TTI 2.5" system on my Barracuda. Headers to H-pipe to 2.5" Dynomax Super Turbos to turn downs at the rear bumper . It's not bad at all.

Is the noise in the Duster across the board, or only resonating at certain RPMs/MPH?

To tame down the 3" across the board, you might be able to swap out the Super Turbos under there for some longer body Hemi Super Turbos (I don't know if they make a 3" version) or a pair of longer body Ultraflows. Would take some tweaking of the pipes to get them to fit, but you won't be scrapping them.

The next option would be to put some glass packs/Race Bullets in the area between the rear axle and tips, on the sides of the gas tank. I know that area is pretty tight on my Barracuda with the 2.5" pipes. Maybe neck it down to 2.5" at the glass pack/race bullet to gain some clearance. Won't hurt flow at that point.

You could try some soundproofing the interior.

What about adding sound deadeding material to the car and leaving the exhaust?

Edit: Damn you quick draw Bill!

Had Super Turbo's 2 1/2" on my C4 and they were terrible. Whole car buzzed and resonated. Replaced with plain 'ol glasspacks and was much, much better. Later dropped the big bucks on a Corsa system and totally loved it.

http://www.dynomax.com/mufflers.php?muffler=racebullet

Putting one on my car dropped it from 100+dB to low 90's. Putting a second one in line dropped it to mid-80's.

Rustspecs13 wrote: turbos, 2 or 4 of them. ~Alex

Obviously the best solution.

Simple 3 step process:

1 Put your hand on the key.

2 Turn key counterclockwise.

3 Enjoy the quiet.

arent there some baffles that can slip into the outlet flanges of some headers? that might help. Also sound deadening material under the carpets helps a lot, and some materials are better than others.

Make sure the exhaust exits past the rear bumper or at least exits in a pair of turn downs. A lot of noise and resonance is worsened by exhaust that exits under the car.

The Dynomax Super Turbos aren't the greatest chambered mufflers for killing noise. I'd look at bigger mufflers of similar configuration that can fit in place of the super turbos. Walker and Magnaflow are both good alternative brands. Spintech is another that I've not heard much about, but they look interesting.

The only issue with glasspacks are that the fiberglass packing burns up over time and they get louder and louder. Stainless steel packed mufflers last a little longer, but aren't cheap.

I've been a big fan of Thermal Research and Development mufflers for a long time.

I know it's not really comparable, but I ran a 2.5" single exhaust on my S52 with no resonator/cat and just one oval TR&D muffler. It was quiet as stock at idle and cruise, growled like a beast under WOT and still didn't have nearly any of the straight 6 rasp so common in aftermarket exhausts.