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Post by chcknugget on Mar 22, 2005 13:27:28 GMT -5
Hello,
I've heard of mufflers and expansion chambers and I know what they look like, but what is the actual performance difference between the two?
I assume mufflers just quiet down the exhaust, but it seems like expansion chambers may improve performace somehow.
Also, is the biturbo exhaust a type of exhaust, or is it for a specific type of bike?
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Post by EJ on Mar 22, 2005 15:59:37 GMT -5
An expansion chamber applies to 2-stroke engines only. It uses sound waves to pull/push a fresh charge into the cylinder. Versus a straight head pipe, a well designed expansion chamber can yield better performance. Here's a detailed explanation on 2-stroke expansion chambers: www.motorcycle.com/mo/mcnuts/em-pipes.htmlAnd your right, mufflers are used to quiet the exhaust noise, but the muffler design also plays a part in performance. The Bi-Turbo is just the name of an exhaust made for Tomos, Puch and some other 2-stroke mopeds. I don't believe the term "Bi-Turbo" has anything to do with the design. |
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Post by chcknugget on Mar 22, 2005 19:33:44 GMT -5
Thanks for the reply,
So what type of exhaust is ideal for a 4 stroke? I'm thinking of fabricating some pipes up this summer.
I had a 43cc 2 stroke ebay scooter and I broke the pipe off by mistake. It really helped acceleration, and throttle response was amazing. I figure it should have hurt to have no backpressure, but it didn't feel like it.
It sounds like mufflers are not necessary (except for noise violations) with 4 stroke engines. Would I gain the best performance by running a straight pipe?
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Post by aeholton on Mar 28, 2005 12:04:29 GMT -5
You need to re-jet the carb and change intake arrangement if you run straight pipe. Otherwise, it can run too lean and burn the top of the piston.
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Post by Steamboat on Mar 28, 2005 13:40:44 GMT -5
Next time you see a Nascar race, look at the stove pipes they run. Jm.
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Post by aeholton on Mar 28, 2005 14:32:34 GMT -5
Yeah...but they also have free breathing intakes and jetting to match. They also tear down and rebuild the engine after every race.
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Post by Steamboat on Mar 28, 2005 14:56:13 GMT -5
When you are running for that kind of money, you use a new engine for each race but the people who run on saturday night get as many runs as they can some times a whole season. It is strange to be at a Nascar track during practice and see the crew doing plug chops just like we do. PS a couple of years ago they would use a new engine to qualify and a new one to race. The little man doesen't have a chance. Jim.
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Post by Kevin on Mar 31, 2005 21:29:06 GMT -5
 Whats a plug chop?
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Post by Steamboat on Apr 1, 2005 10:34:49 GMT -5
www.mopedarmy.com/forums/discuss/read.php?f=7&i=12772&t=12771 ---This is from the Moped Army Forum but it will explain a plug chop. 2-stroke mopeds are built to be inexpensive transportation with low Hp, are run wide open much of the time and are very sensitive to any change in the fuel or exhaust system so when a change is made they have to change the carbs main jet to keep from running a lean mixture. In Nascar racing the engine runs near wide open most of the time so they do plug chops to find the proper jet for that throttle setting. Jim.
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Post by mark on Apr 13, 2005 20:11:15 GMT -5
Look for helix pipes on ebay they are awsome bolt ons it made my bike sound like a harley  |
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Post by chcknugget on Apr 13, 2005 21:29:47 GMT -5
Look for helix pipes on ebay they are awsome bolt ons it made my bike sound like a harley What kind of scooter do you have? The Honda Helix is a 4 stroke, and I wonder how my geely 4 stroke would handle the muffler! |
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Post by mark on Apr 25, 2005 20:10:02 GMT -5
I have a GL-50 by Jialing
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