flow with silencer in ???

dumbskate · Post by **dumbskate** » Wed Apr 13, 2005 9:29 am

im getting a straight through muffler put on and as it comes with a silencer that looks like it's only 1 1/2 inches in diameter i was wondering if i will still get the same free flowing benefits with it in ??

i hoping to leave it out but until i get another resonator in there n/a + straight through muffler = very noisey

azn2nr · Post by **azn2nr** » Thu Apr 14, 2005 8:02 am

no. youll have more back pressure than you did before.

maybe its because i have 2 resanators and a muffler but my 3 inch system isnt loud at all. i mean it is compared to stock but compared to a hks or a blitz its not. my resanators and muffler are all 3inchs id so there is no restriction

BAC5.2 · Post by **BAC5.2** » Thu Apr 14, 2005 8:50 am

Mufflers and resonators DO offer restriction, reguardless of their ID.

A straight through muffler with a 3" ID still has area in which exhaust is vented into baffling (all of those holes in the muffler/resonator). The exhaust is then blown around in and out of that baffling creating turbulence and restriction.

A 3" straight pipe will flow better than a 3" pipe with resonators and mufflers.

As far as the silencer setup, it depends on the design. If it's a cone type that's very long (sits deep into the exhaust) and doesn't simply BLOCK flow (really rudamentary way of reducing noise), it will flow almost the same as without it, but it will create turbulence at the end of the exhaust which will baffle noise very slightly.

Summit sells deep cones who's open area has greater surface area than the diameter of the pipe it's placed in. They are designed for cars running open header at the track, just to take some of the edge off of the noise.

The question is... It's on an otherwise stock or mildly modded N/A, so does it matter? Will you be taking advantage of the additional flow? Probably not. So if you like the noise of the no silencer, go for it, otherwise toss it in and rejoyce. Either way, you most likely won't notice a performance difference.

VRoman · Post by **VRoman** » Fri Apr 22, 2005 2:09 am

Please explain me, why a resonator would restrict the flow? Isn't it empty from the inside?

BAC5.2 · Post by **BAC5.2** » Fri Apr 22, 2005 2:17 am

It's an open chamber with baffling inside of it. The inner diameter of the resonator might be 3 inches, but the resonator chamber might be 4 inches, which allows the air flowing through to expand into the resonator area of the muffler, and thus slow down creating restriction.

A 3" straight pipe will flow better than any resonator or muffler.

dzx · Post by **dzx** » Fri Apr 22, 2005 2:19 am

No, the sound waves have to be made to bounce back and forth to cancel each other out and therefore the gases would also bounce around creating back pressure. At least thats how i see it happening.

VRoman · Post by **VRoman** » Fri Apr 22, 2005 2:36 am

How much back pressure do you expect from adding a resonator?

dzx · Post by **dzx** » Fri Apr 22, 2005 2:41 am

Less than a muffler. I think it would depend on the company and maybe the design of the resonator. But I'm definately not an expert on exhaust so maybe someone else will chime in here.

BAC5.2 · Post by **BAC5.2** » Fri Apr 22, 2005 3:45 am

dzx wrote:No, the sound waves have to be made to bounce back and forth to cancel each other out and therefore the gases would also bounce around creating back pressure. At least thats how i see it happening.

A lot of times, don't resonators absorb sound waves and muffle them much like a pillow does? Slowing the air down in order to muffle the noise?

That's how I see it at least...

VRoman - Probably not a lot. Let's put it this way. I'd probably only make 2 more whp if I had a straight pipe. An insignificant amount, for sure. But restriction all the same, and when you are pushing for every last ounce of combustible power output, that could mean the difference.

dzx · Post by **dzx** » Fri Apr 22, 2005 5:22 am

Resonators are like glass packs right?

BAC5.2 · Post by **BAC5.2** » Fri Apr 22, 2005 5:24 am

There are all kinds of resonators, which usually are composed of a perforated tube (the main tube) inside a larger tube with some sort of sound dampening material between the two tubes. Exhaust gas bleeds out of the holes in the main perforated tube, and is slowed down by the dampening material, and is forced back into the flow by more air entering the perforations. Hence, turbulence and restriction in flow.

At least that's how I see it, but I'm no fluids engineer...

dzx · Post by **dzx** » Fri Apr 22, 2005 5:35 am

Ok, i took the time to look it up. Resonator has the base resonance and resonance is two frequencies that cancel eachother out. Which is why if you match the specific natural frequency of an object, it will break apart. (i.e. a rock)

http://auto.howstuffworks.com/muffler3.htm

The sound waves actually travel down the exhaust faster than the gasses. So slowing down the gases wouldn't necesarily quiet the car. This was taken from the muffler section but im sure a "pure" resonator would work pretty much the same way as just a resonator.

A chamber called a resonator is connected to the first chamber by a hole. The resonator contains a specific volume of air and has a specific length that is calculated to produce a wave that cancels out a certain frequency of sound.

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flow with silencer in ???

flow with silencer in ???