fladawg
Big Dawg
my poor scoot
Posts: 22
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Post by fladawg on Aug 22, 2006 18:44:05 GMT -5
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Post by mgreenfield on Aug 22, 2006 19:36:27 GMT -5
A waste of $$. Much more effective at reducing pressure drop in length of pipe is simply increasing inside diameter of single pipe.
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Post by sussexscooterhead on Aug 24, 2006 8:09:42 GMT -5
But as a way of balancing noise and flow wouldn't this be a good idea?
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Post by mgreenfield on Aug 24, 2006 8:43:28 GMT -5
Nah. Noise suppression is a function of muffler design. Flow is mostly a function of area of the pipe ID. A 1" ID pipe has 0.79sqin of area. Two such pipes would have a combined 1.58sqin of area. A single 1.375" ID pipe has 1.48sqin of area.
However, there's friction of the flow against the walls of the pipe, which is also a function of pipe diameter. The single 1.375" pipe will have 30% less pipe wall in contact with the flow when compared to the two 1" pipes.
So, just going from 1" ID pipe to 1.375" ID pipe will easily double the flow capacity of the pipe. And one pipe is lots easier to work with than two.
Resonant exhaust pipe design for 2-stroke engines is an entirely different game, full of magic and witchcraft, and I know zip about this.
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Post by sussexscooterhead on Aug 24, 2006 9:17:13 GMT -5
Not that I have a vast amount of experience in the matter but I've never seen differences in muffler design when it comes to performance exhausts. They all seem to be straight baffles in packing.
How would you propose redesigning the straight through baffle in order to reduce noise?
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Post by mgreenfield on Aug 24, 2006 13:57:15 GMT -5
Not a clue. I suspect this game is one of doing a barely-good-enough job at silencing, at the lowest possible manufacturing cost. Assembling the bits/pieces of baffling/tubing into an OK muffler at a decent production cost has to be a challenge with lots of trade-offs.
An ideal muffler would probably be dead silent, have zero backpressure, weigh half as much, BUT cost 50-times more than the ones we get.
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Post by sussexscooterhead on Aug 24, 2006 14:30:22 GMT -5
Well, because I like the discussion of ideas, I'll continue the conversation. I think you're dismissing this idea a little too hastily. I don't know how well this Turbo pipe works and don't much care for it's looks but think the notion of increasing baffle area while not increasing restriction is a good idea and the engineers at Honda and Yamaha would seem to agree with me. powersports.honda.com/motorcycles/motocross/model.asp?ModelName=CRF250R&ModelYear=2006&ModelId=CRF250R6www.yamaha-motor.com/sport/products/modelimage/6/19/2/0/image.aspxYour earliler numbers are correct, a 1.375" diameter pipe would flow more than 2 of 1"dia. but no one is saying two 1" pipes are the only option and what I was getting at is that flow isn't the only concern. A muffler's job is to muffle and the performance mufflers do this by allowing the packing to absorb energy. So if we can put together something with a larger 'absorbtion area' while not reducing flow, wouldn't this make sense? |
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Post by mgreenfield on Aug 24, 2006 15:24:15 GMT -5
Sure, ....as long as you could find a place to hang it/them on the bike, and didnt add ton of weight and expense. And sometimes it is easier to find a flat space to squeeze in two 1" pipes rather than a larger space for a single 1-3/8" pipe. But I think the biggest factor is styling. Single fat stack is ugly. Two smaller pipes are symetrical & pretty.
Some mufflers have no packing. Just baffles.
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Post by Admin on Sept 7, 2006 14:57:48 GMT -5
Joel Martin (MRP) told me the pipe was great....but he doesn't always know. He was going to send me one but then didn't follow through and sent some other stuff instead. Also, I've got to say it. I can't recommend Miamimoto as a place to purchase anything. You can trust our friend Stan for such orders and cbxman is also now an MRP dealer. I and some others have had very bad experiences with that other place.
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