Exhaust Info
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Joined: Feb 2008
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From: Atlanta, Ga.
Exhaust Info
I am considering an upgrade of my current exhaust for my sportster 1200C. Currently I have the stock pipes. In doing some research I found that equal length pipes perform more efficiently. Has anyone found this to be true in their experience with exhaust systems? This information I received from 'BigCity Thunder.'
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If you think of the cylinders as two seperate engins, which they are, then to keep them the same even equal length is best.
Now you have to take into consideration how many radious, bends, there are and how hard the bend. There are formules that you can use to figure bends and length to come out with a "Equal length" but I am old now and forget them. Somebody knows.
Longer helps torque, shorter causes "peakie engines" that are loud and not really good for preformance, except at 6000RPM. Which I haven't hit in 20 years with a Harley.
2 into 1 generally preforms best and the Manufactures try and get length equal as they can. But who runs these on a Sportster as I reread your question.
Then you get into pipe dia, collector size and collector length.
There are a bunch of good pipes for a Sportster Just don't go too short and probably will have to rejet.
Have fun.
Now you have to take into consideration how many radious, bends, there are and how hard the bend. There are formules that you can use to figure bends and length to come out with a "Equal length" but I am old now and forget them. Somebody knows.
Longer helps torque, shorter causes "peakie engines" that are loud and not really good for preformance, except at 6000RPM. Which I haven't hit in 20 years with a Harley.
2 into 1 generally preforms best and the Manufactures try and get length equal as they can. But who runs these on a Sportster as I reread your question.
Then you get into pipe dia, collector size and collector length.
There are a bunch of good pipes for a Sportster Just don't go too short and probably will have to rejet.
Have fun.
Last edited by Old Gunny; Oct 2, 2008 at 01:38 PM.
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Joined: Jul 2007
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From: Indy area
I'd like to add that although the two cylinders share the same intake material, they operate at different temperatures, thus have slightly different tuning needs. To get them to equally contribute to the whole output (as opposed to, say, strictly the most power each can make), which I'd consider the ideal situation, it just might take a slightly different length exhaust on one vs. the other. So in this respect, "equal length" could be a relative term and not a strict one. I don't have any particular thing or suggestion in mind, just saying that a very successful exhaust system may or may not have pipes the exact same length, and one which does have them perfectly the same may not be the most successful in providing a smooth-running engine. There are other factors also involved.
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