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Post by g2kmobile on Nov 14, 2015 19:35:58 GMT -5
Hi all, I have a gutted muffler that was originally for a 50cc motor. I am wondering if, assuming it will bolt up to the head, a gutted muffler for a 50cc will provide proper back pressure for a 150cc motor? 1) Will the gutted muffler create too much back pressure? 2) Will the gutted muffler be about the same back pressure as a stock muffler? 3) Will the gutted muffler have not enough back pressure? I would love to hear the feasibility of this idea, and your thoughts on this, thanks.  |
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Post by pistonguy on Nov 14, 2015 20:08:14 GMT -5
I dunno if the Fiddy fart Can gunna fit a One Fiddy. But All that Back pressure stuff has Much More Effect on a Two Smoker. Sound Waves in Heat Mediums work With Back Pressure to Scavenge Exhaust. Jetted Correctly yo can run on the Head Pipe Alone if ya wanted. The Gutted Can has Removed Most of the Back Pressure. I dunno why anyone does this and Skips the Head Pipe is Smaller than the Exhaust Port and Most Likely the Flange is Welded Off Center Blocking More of the Exhaust Port.  You Squirting into a Straw. Free Flow Systems are Available with Larger Stainless Dia. Head pipes for under $80 bucks.  Just Going to Annoy the Neighbors with a Gutted Fart Can  |
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Post by pistonguy on Nov 14, 2015 20:08:49 GMT -5
Hi all, I have a gutted muffler that was originally for a 50cc motor. I am wondering if, assuming it will bolt up to the head, a gutted muffler for a 50cc will provide proper back pressure for a 150cc motor? 1) Will the gutted muffler create too much back pressure? NO 2) Will the gutted muffler be about the same back pressure as a stock muffler? NO 3) Will the gutted muffler have not enough back pressure? Not Relevant. I would love to hear the feasibility of this idea, and your thoughts on this, thanks. |
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Post by scooter on Nov 14, 2015 20:37:08 GMT -5
I don't have an educated guess. I don't know the pipe diameters or lengths, the dimensions of the inside of a 150 exhaust, or how exhausts work on a deeper level than "air comes out of that hole". There are issues with pressure and inertia of flow, etc that I don't know anything about. As usual though, I believe there's more to it than "more air is better".
According to wikipedia, you'll get some difference when you change the design of the pipes, like more power at low rpm, or more power at high rpm, increased fuel use, etc.
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Post by lain on Nov 14, 2015 21:03:52 GMT -5
Things to think about are the pipe inner diameter and header size, if the 50cc pipe is thinner in diameter than the 150cc then it will obviously have some bit of a restriction, but like others have said the exhaust pressure or lack of does not effect a 4 stroke much, that's why exhaust mods are usually left to be the last things or not done at all on most 4 strokes. On a 2 stroke exhaust pipes can make or break the entire setup.
If you removed everything from the inside of the muffler can, then it basically has no use and there isn't any point in having it except to shape the sound leaving the pipe but would not muffle without the fiberglass packing stuff in it.
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Post by cyborg on Nov 15, 2015 10:41:43 GMT -5
I am in pistons camp on this one,,,the less restriction the better on a 4t,,,,proper carb/injection setup required for fuel/air ratio but the best results on a 4t is free flow exhaust
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Post by JerryScript on Nov 15, 2015 10:56:27 GMT -5
It would be interesting to see some results comparing stock, free-flow, and 2T expansion chambered exhuasts on a 4T.
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Post by g2kmobile on Nov 15, 2015 19:50:38 GMT -5
I currently have one of those generic "free flowing" exhausts sold online and the sound is actually quite nice. The system offers good low end, quick(er) mid range, and tapers off on the high end.
My curiosity stems from the fact that I happened to ride a completely stock scooter that is the exact make/model as mine. His scooter seems to have the same top end ~60 - 65 mph, while mine has quicker mid range: say from 40 - 55 mph. We both seem to have decent bottom end speed.
So I was wondering if I took a 50cc muffler that was gutted would I be able to achieve the same performance, without having the extreme LOUDNESS, that my "free flowing" exhaust has? Since these "Hi-Perf" mufflers don't seem to do very much over "stock" mufflers.
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Post by pistonguy on Nov 15, 2015 20:19:23 GMT -5
It would be interesting to see some results comparing stock, free-flow, and 2T expansion chambered exhuasts on a 4T. A 2-T wouldn't work at all. Two Smoker Pipe tech is Deeep. It works with Sound Waves and Heat Medium's, Sound works better within higher heat mediums. The System Scavenges (sucks) Exhaust and Helps (sucks) the Incoming Charge from The Transfer Ports. The Sound is controlled by Two or more Cones of various Angle and Lengths with a Medium (Chamber) of Various Lengths and end'd with a Skinny Stinger. Sometime's a Silencer on the End also of various lengths for different tunes. Short generally is Low-Mid Power. Here is a Working Fatty, Stinger on the end is tiny compared to the Exh. Port  . This motor is so built around a working pipe its simply Wont Run Without it. Port Timing, Squish Angle, are Altered for a Low-Mid range Power Monster. A Shorty Ti Silencer was fitted to the Stinger |
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Post by pistonguy on Nov 17, 2015 16:30:13 GMT -5
I currently have one of those generic "free flowing" exhausts sold online and the sound is actually quite nice. The system offers good low end, quick(er) mid range, and tapers off on the high end. My curiosity stems from the fact that I happened to ride a completely stock scooter that is the exact make/model as mine. His scooter seems to have the same top end ~60 - 65 mph, while mine has quicker mid range: say from 40 - 55 mph. We both seem to have decent bottom end speed. So I was wondering if I took a 50cc muffler that was gutted would I be able to achieve the same performance, without having the extreme LOUDNESS, that my "free flowing" exhaust has? Since these "Hi-Perf" mufflers don't seem to do very much over "stock" mufflers. Oh Its too LOUD like mine. Gotcha Without pics to see you saying the oe Fiddy Can is longer/larger, gutted should be quiter than the free flow fart can. Probably. This is the only pic I have of a OE 150, is the Top one. The Head Pipe is my concern. its tinny and Smaller than your exhaust port, not good. Do you have Stock Intake? You Wont get much out of Just a Exh mod. Its All About the Combination. Intake and Exhaust  |
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