Whats the difference between mufflers and resonators?

[ihavearustedz]

Really why does a muffler cost as little as 20 bucks and resonators start at about 70 (summitracing). And my real question is I have a 2.5 inch straight pipe exhaust with a Megan racing muffler on the end (looks something like this http://www.pdm-racing.com/products/i..._Exhaust_b.jpg ) but its kinda loud. I was under the impression that a resonator would do a better job of controlling the sound. Its too loud for me right now. Do you think i would be fine a with a glasspack muffler or go with a resonator like

http://store.summitracing.com/partdetail.asp?autofilter=1&part=HSH%2D12512300&N= 700+4294923429+4294922711+4294804382+4294891681+11 5&autoview=sku

 

thanks.

[jerryb]

(Wikipedia)......Automobiles

A resonator is one part in exhaust systems that works with the muffler to reduce noise, by making sound waves "cancel each other out"[1]. The "exhaust note" is an important feature for many vehicle owners, so both the original manufacturers and the after-market suppliers use the resonator to enhance the sound.

 

I believe the net effect of a muffler/resonator install will vary depending on how far apart they are, relative sizing of the two, engine type and even the rpm range they impact.

 

My resonator made the car sound deeper but it didnt really make the car more quite....I guess it wasnt as barky.

[e_racer1999]

i read on here that the only real difference is where it's placed. as mentioned above, the resonator is designed to reduce/eliminate resonance (hence the name) and the muffler is designed to make the full sound quieter.

[MJLamberson]

so its kinda like they serve a similar purpose but do it in different ways

[Tony D]

Yes, where they are placed determines their function. It is not necessarily resonator/muffler, or muffler/resonator. There may be multiple resonators to take out different harmonics or accoustic signatures.

 

Generally Mufflers have chambers which the gasses pass though in some fashion, and 'trap' accoustic signatures through change of direction. Resonators usually are simply straight through chambers that add volume at a given place. They may have baffles, there may be glass wool packing, or it may be simply a 'bulge' in the piping to add volume to the exhaust system. If there are chambers and change of direction involved within the unit, chances are very good it is NOT a resonator, it's a muffler---and anything else in the system is either a catalyst or resonator!

 

A muffler will work almost anywhere in the system, but a resonator requires very careful and specific placement to do what it does. Because they accomplish the noise reduction in different ways, it becomes critical that the resonator be placed at the proper location for maximum effect. Put a glasspack at the headpipe, and listen. Then put it at the end of the exhaust system... Totally different accoustic signatures. Because it's more suited for 'resonator' duty, it's placement within the system will change how it sounds. Then try it with a Flowmaster...sounds the same...may not be flowing the same, but that is the biggest difference between muffler and resonator.

 

More correctly than saying they serve similar purposes, but do it in different ways would be to say that a muffler is a 'general purpose' noise reduction device---it works on a broad spectrum of signatures. While the Resonator is a very specific tool that is designed and placed to remove specific noises (the boom at 2500 rpm that happens on 2.5" exhausts, it's a midrange drone that gets resonant and amplifies itself 3X near the low end of the torque plateau, for example).

 

A neat trick is to listen and see when your exhaust gets the quietest when on the road. It tells you a lot about the design of the system. My buddy had a Trust System on his Box Skyline, and as we were driving down the expressway one day at 140kph, we came to the sudden realization that the exhaust note was TOTALLY absent. Slowed down to 135 and like someone hit the stereo loudness switch bwaaaAAAAA. Speed back up to 140, and as you neared 138 it started getting quiet, and by 140 the exhaust was totally silent. From that point it was like 'starting over' as the exhaust started getting louder again at 145 and up... We noticed this was different depending on load in the vehicle as well. When 4 people were in it, silence occurred at 140 kph. With only 2 people it was closer to 120 kph... Obviously engine load has a bearing on the noise signature.

[Evan Purple240zt]

Tony, my exhaust has a pair of resonators on it. It is down right loud at idle and load but under normal cruise its quiet. Good design I suspect.

 

However, I have noticed I can totally kill the note alltogether if I drive close enough to the concrete barrier in the center of the road. The cancellation is just right, which obviously changes by how close to the barracade I am.

 

Cool stuff.

 

Evan