tuned pipes
03-15-2008, 09:54 AM
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tuned pipes
Hey guys,
Did some searching and seems there is very little info on this topic.
I am wondering about the gap between header and pipe and what safe distances are? I seem to recall reading something about if you get too large you can melt the coupler? My setup is a bit too peaky for me and right now it's at 1/2" gap.. wondering what range is aceptable?
Did some searching and seems there is very little info on this topic.
I am wondering about the gap between header and pipe and what safe distances are? I seem to recall reading something about if you get too large you can melt the coupler? My setup is a bit too peaky for me and right now it's at 1/2" gap.. wondering what range is aceptable?
03-15-2008, 10:14 AM
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RE: tuned pipes
Rudy
I was thinking the same thing, how big of a gap is acceptable? I thought about a way to make adjustments and I came up with the idea of taking 1 inch aluminum tubing and cutting 1/2, 1, 2, 3 inch pieces. The coupling is about 4 inches long so you could slide the pieces between the header and the pipe, just let it "float" there and connect the ends normally.
What engine/header/pipe/prop are you using? What rpms are you getting? Is there a specific rpm that the pipe comes on at?
I was thinking the same thing, how big of a gap is acceptable? I thought about a way to make adjustments and I came up with the idea of taking 1 inch aluminum tubing and cutting 1/2, 1, 2, 3 inch pieces. The coupling is about 4 inches long so you could slide the pieces between the header and the pipe, just let it "float" there and connect the ends normally.
What engine/header/pipe/prop are you using? What rpms are you getting? Is there a specific rpm that the pipe comes on at?
03-15-2008, 11:33 AM
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RE: tuned pipes
You can always try it and see. I put this setup together a while back. After running it a while, I could touch the pipes without getting burned. They weren't as hot as I thought they would be. There's about a 1/4" of space between the header and pipe. I haven't made a mount yet for the pipes. I ran it anyway and was getting about the same RPM as before. I have long headers though. The needle is still responsive. I'm going to wait till after it flies before I do any cutting. Pipes sound alot better than the cowl mufflers.
03-15-2008, 01:37 PM
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RE: tuned pipes
I found this on my work bench, it's one of the canisters off a 3W 106. The coupler is about six inches long, about 3 1/2 inches appear to have been between the header pipe and the canister, no apparent damage to the coupler.
03-16-2008, 05:50 PM
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RE: tuned pipes
For testing I use two header lengths and a looong teflon coupler, than can be adjusted like a trombone. No signs of distress in the coupler., as long as the header does not touch the pipe.
03-16-2008, 06:03 PM
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RE: tuned pipes
Pe
How long of a header would you start with on a 60cc that you want to turn 8500rpm? Will I see any tune effect if I make a intake manifold that's longer than the stock carb block on a MT62(G-62)?
How long of a header would you start with on a 60cc that you want to turn 8500rpm? Will I see any tune effect if I make a intake manifold that's longer than the stock carb block on a MT62(G-62)?
03-17-2008, 01:52 PM
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RE: tuned pipes
ORIGINAL: soarrich
Pe
How long of a header would you start with on a 60cc that you want to turn 8500rpm? Will I see any tune effect if I make a intake manifold that's longer than the stock carb block on a MT62(G-62)?
Pe
How long of a header would you start with on a 60cc that you want to turn 8500rpm? Will I see any tune effect if I make a intake manifold that's longer than the stock carb block on a MT62(G-62)?
I wold start at about 400mm (16" ) and work down from there.
Use a set of four props to test each header length (20x10, 22x8, 22x10, 22x12). Plot rpm, and the power taken from my prop power calculator.
You now can draw the power curve and see where the engine peaks. If peak power location is lower than 8500, shorten the header 1" at a time.
By plotting the power curves, you also can see if the engine gets more peaky or not. If the power curve gets wider at the top, you are approaching the engine sweet spot. If it narrows, you are moving away from it, and the obtained extra power will cost you in terms of throttle response.
03-17-2008, 02:32 PM
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RE: tuned pipes
Pe
Thanks, I'll have to get the 22x10 and 22x12 so I guess it'll be a month before I can give the results of my testing. I used your power calculator on a LS Pro/GR Pro 50cc motor it seemed to be dead on on thrust, it said 19 pounds of thrust and my 17 pound plane could just pull up from a hover.
Thanks
Rich
Thanks, I'll have to get the 22x10 and 22x12 so I guess it'll be a month before I can give the results of my testing. I used your power calculator on a LS Pro/GR Pro 50cc motor it seemed to be dead on on thrust, it said 19 pounds of thrust and my 17 pound plane could just pull up from a hover.
Thanks
Rich
