VR_IV_MR
Well-known member
I recently threw in 3g lifters, but would solid lifters be quieter? Are there any reasons that I shouldn't use solid lifters?
Will an upgrade to evo springs/retainers or titanium springs/retainers make the engine run quieter?
Will a resonator or a muffler be better?
Will dynamat or a similar material be beneficial if it is only used on the firewall and floor? (and not in the doors and ceiling)
Is there anything else that is noise related that I should know about? My engine bay is particularly loud- not my exhaust.
can anyone confirm some of the following information that i found on a Z forum? where is the rpm range where our cars create the drone? will it be different with 2.5" or 3" pipes? or different cams/turbos/etc?
Quote:
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.
Will an upgrade to evo springs/retainers or titanium springs/retainers make the engine run quieter?
Will a resonator or a muffler be better?
Will dynamat or a similar material be beneficial if it is only used on the firewall and floor? (and not in the doors and ceiling)
Is there anything else that is noise related that I should know about? My engine bay is particularly loud- not my exhaust.
can anyone confirm some of the following information that i found on a Z forum? where is the rpm range where our cars create the drone? will it be different with 2.5" or 3" pipes? or different cams/turbos/etc?
Quote:
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.
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