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/cgi-bin/YaBB.pl General Category >> Rubber Side Down! >> Home made exhaust question /cgi-bin/YaBB.pl?num=1349697230 Message started by Greg on 10/08/12 at 04:53:50 |
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Title: Home made exhaust question Post by Greg on 10/08/12 at 04:53:50 I am going to try my hands at another exhaust/muffler. I am wondering about the baffle. Does it need to go at the end or could it go in the front near the head pipe? |
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Title: Re: Home made exhaust question Post by Dave on 10/08/12 at 06:33:13 The idea of a baffle is to even out the pulses - which will reduce noise by smoothing out the pressure pulses. Ideally you want to have a resonance chamber where the sound can bounce around and leave the tailpipe in even flow....instead of pressure waves. This is not completely possible on a big single - but the more restrictive the baffle and the larger the resonance area....the more effective it will be. I am currently of the opinion that a muffler with a baffle reduces noise in the lower frequencies more effectively than the higher ones, and a baffled muffler makes a higher pitched exhaust note.....while mufflers that have a perforated core and sound batting make a lower exhaust note as the packing absorbs the higher pitched sounds more effectively. So......I believe the baffle should be about in the middle - with room to resonate on both sides of the baffle. The Harley Dyna muffler has a center pipe with a holes on both sides of plug. The exhaust comes down the small center pipe and then goes through holes into the large outer shell where the pulses can even out.....then it goes through holes back into the center pipe and out the rear. Installing a baffle without a chamber for the exhaust to resonate will not be nearly as effective. |
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Title: Re: Home made exhaust question Post by Gyrobob on 10/08/12 at 07:12:57 The more pipe you have downstream of the last baffle, the deeper the tone. Conversely, if you have the baffle at the very end of the muffler, you'll get a flat tone. Unless you have a pretty big muffler it is hard to get a deep tone (a manly sound) AND have it quieted down much. |
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Title: Re: Home made exhaust question Post by Charon on 10/08/12 at 08:23:12 You really need to make some preliminary decisions about what you want the system to do. Is it supposed to be quiet (or loud), is it supposed to enhance performance, or look good, or some combination of the three? If it is to enhance performance, you need to decide where in the RPM range that is to happen, because that affects the placement of the baffle as well as the location of the expansion volume where the header enlarges into the muffler(reflected pulses). If it is to be quiet, larger volumes are more effective than smaller. Appearance is in the eye of the beholder, of course. Naturally, all this has to be done within the rather limited space available on a motorcycle. |
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Title: Re: Home made exhaust question Post by justin_o_guy2 on 10/08/12 at 08:39:28 Have you decided a Dyna just isnt gonna work for you? |
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Title: Re: Home made exhaust question Post by Greg on 10/08/12 at 10:58:35 Thanks everyone. JOG, I am well past the Dyna. Not nearly loud enough. I am running a Screamin' Eagle that is just a little to "lawnmower-ish" sounding and just a hair loud. That is the one the baffle was rusted in. I did get it out to the end but still can't finish removing it. Anyway, I want it almost as loud as the Screamin Eagle. I don't want high pitch sound. I don't expect a deep sound from a single, but don't want something that makes my ears bleed. I still want to do an upswept fishtail. I can get the extension fairly cheap but it has no baffle. I can't install it at the outlet due to the fishtail. So, from what I am reading here, if I install it towards the inlet end and wrap it in glass/steel, it should tame the high pitch and be as low sounding as possible. I am not figuring on any performance gain. That is not my goal. Looks and sound, which are both subjective, are my goals. |
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Title: Re: Home made exhaust question Post by Arnold on 10/08/12 at 11:52:23 I went from screamin eagle with no baffle (was pretty loud, nice sound, not high pitch, that rusted out eventually) to a HD pull out fishtail, has the original baffle, pretty quiet now, I kinda miss the noise. |
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Title: Re: Home made exhaust question Post by CalisOsin on 10/08/12 at 16:20:39 Have you went and listened to the "Sounds" page yet? http://suzukisavage.com/cgi-bin/YaBB.pl?num=1151331237 I'd give these a listen and maybe that will help you make a decision. |
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Title: Re: Home made exhaust question Post by Cavi Mike on 10/08/12 at 17:12:15 79424F5849455E58434B46592A0 wrote:
A baffle is a perforated core. What you seem to be calling a baffle are those half-round plates that are welded into exhausts. They are restrictor plates, not baffles. Those restrictor plates are what cause that tingy high-pitched sound - the rasp you tend to hear. A cheap and easy way to bring an exhaust note down at a specific RPM but can also amplify other frequencies and due to their design as "restrictor" plates, they do exactly that - restrict the exhaust flow. A long, large diameter baffle with some type of packing around it is going to give the lowest exhaust note possible. Those short small-diameter things that pop into the end of the pipe aren't going to be enough to bring the note down. Look up some replacement baffles for other exhausts that will fit your dimensions. I used a Cobra replacement baffle in mine. |
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Title: Re: Home made exhaust question Post by Greg on 10/08/12 at 17:26:05 1C3E29361236343A5F0 wrote:
What are your thoughts on the placement of the baffle, inlet or outlet? |
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Title: Re: Home made exhaust question Post by Cavi Mike on 10/08/12 at 18:13:57 I guess it depends on how large your pipe is. If it's large or mega-phone shaped, the exhaust is going to get amplified if the baffle is at the inlet. If the outlet is small in diameter, I don't think it's going to make much of a difference. |
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