"Birddog" (maintmgt)
10/29/2015 at 12:00 • Filed to: None
3
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"Birddog" (maintmgt)
10/29/2015 at 12:00 • Filed to: None | 3
| 21 |
I ran across this while searching for “off-road” exhaust pipes for Crusty.
I’m not an expert on exhaust systems but I’m pretty sure multiple, tight radius bends is a bad thing.
spanfucker retire bitch
> Birddog
10/29/2015 at 12:02 |
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Has Science gone too far?
HammerheadFistpunch
> spanfucker retire bitch
10/29/2015 at 12:08 |
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or not too far enough?!
CounterTorqueSteer
> Birddog
10/29/2015 at 12:10 |
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F1 would like to disagree with you.
Azrek
> Birddog
10/29/2015 at 12:13 |
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This is how the tow truck can zero in on your location as you are trying to get outta a mud puddle and overreving the engine.
HFV has no HFV. But somehow has 2 motorcycles
> Birddog
10/29/2015 at 12:14 |
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It’s a cheap copy of a muffler Mugen made IDK if they still do or not. There was one on my GSR when I got it. It sounded pretty good actually.
wiffleballtony
> Birddog
10/29/2015 at 12:15 |
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I think I saw something like this on a stanced 350z with a vanity plate that said “eggrawlz.” What are these supposed to do?
gin-san - shitpost specialist
> Birddog
10/29/2015 at 12:17 |
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I actually don’t know what’s going on here - why does the exhaust exhaust into itself?
daender
> Birddog
10/29/2015 at 12:18 |
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I forgot the exact scientific reasoning behind it but that design is to help reduce droning. Pictured above in my comment is an OEM Honda S2000 muffler. Those seeking performance will ditch them instantly because of their heavy weight...only to come back complaining their exhaust drones badly at highway speeds.
AntiLag
> Birddog
10/29/2015 at 12:30 |
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I think they misunderstood what 180° headers are.
Supreme Chancellor and Glorious Leader SaveTheIntegras
> Birddog
10/29/2015 at 12:34 |
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jdm yo
Snuze: Needs another Swede
> daender
10/29/2015 at 12:49 |
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It’s based on wave cancelation. The 2 baffles are placed to give each chamber a certain volume, and the lengths and tapers of the pipes are calculated in such a way that there will be reflections of the waves going through them, such that the return wave strikes the incoming wave 180 degrees out of phase and cancels it out. I believe with that setup you could tune the exhaust to reduce noise at 5 to 6 primary frequencies.
I once designed a single frequency resonator for our FSAE car - the FSAE rules say you only have to be under a certain decibel limit at the engine speed that equates to some arbitray mean piston speed (I think it was 3,000fpm). So you figure out what RPM that is, take a broadband measurement of your sound, determine your frequency of interest, and you can calculate a resonator volume that will return waves 180 degrees out of phase. So our exhaust system just had this random pipe that went off to nowhere and was capped on the end. When you ran the car, you’d hit the gas and it would go BRAAAAAAAA.......AAAAAAAAAAA!!!! It had this weird lull at that specific RPM. Yay for rule bending!
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Snuze: Needs another Swede
> Birddog
10/29/2015 at 12:53 |
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When the exhaust hits the muffler it’s cooled sufficient and dropped a lot of velocity so the bends aren’t as detrimental as they would be say, up at the header. It’s not ideal, but its not awful.
It’s just kind of a weird way to build a muffler. Here’s the guts of a C6 Corvette muffler:
StndIbnz, Drives a MSRT8
> CounterTorqueSteer
10/29/2015 at 13:10 |
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Thats more to do with packaging while keeping them all equal length, but yes.
TheRealBicycleBuck
> Snuze: Needs another Swede
10/29/2015 at 13:15 |
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Performance R/C planes use two-stroke engines with a “tuned” pipe that, through the magic of sound waves, increases the performance of the engine. It does this by creating a high-pressure sound wave that pulls additional air & fuel into the combustion chamber before it closes.
There’s a good article about it here .
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Snuze: Needs another Swede
> TheRealBicycleBuck
10/29/2015 at 13:31 |
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Yeah, its the same theory just used a different way. It’s also how ITBs work - you can change the trumpet length to move the resonance effect up and down the power band.
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TheRealBicycleBuck
> Snuze: Needs another Swede
10/29/2015 at 13:55 |
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Just like a trombone!
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Snuze: Needs another Swede
> TheRealBicycleBuck
10/29/2015 at 14:09 |
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Exactly!
CCC (formerly CyclistCarCoexist)
> Birddog
10/29/2015 at 14:50 |
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Magically adds 20 hp
DarrenMR
> Snuze: Needs another Swede
10/29/2015 at 20:35 |
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Any pics or video of that? Id love to check it out.
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Snuze: Needs another Swede
> DarrenMR
10/30/2015 at 10:24 |
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Sadly no, we only ever messed around with it on the dyno. We ended up abandoning it, for two reasons. One is that we switched from a single cylinder engine to a 4 cylinder. It worked great on the single because you have one primary frequency that’s directly tied to engine RPM. On 4 cylinder your sound profile is a lot different. Also, FSAE changed the way they measured sound and what their limits were. It ended up being cheaper and easier to run 2 mufflers with virtually no weight penalty.
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DarrenMR
> Snuze: Needs another Swede
10/30/2015 at 11:12 |
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:’(