Cross over exhaust Pipes ..Why ?

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Apr 16, 2007 | 11:47 PM

conch54

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6th Gear

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Cross over exhaust Pipes ..Why ?

Dose anyone know the reasoning behind HD use of the cross over exhaust on the dual exhaust touring models , instead of a true dual like are sold by everyone? Just curoius....thanks... Luis in Miami.

[IMG]local://upfiles/28174/0F521A2931DC4057B0B2F6E9C4968246.jpg[/IMG]

Apr 17, 2007 | 12:04 AM

txfxstrider

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RE: Cross over exhaust Pipes ..Why ?

Yes, but the answer is too long and complicated to type now. This info is available almost everywhere.

Apr 17, 2007 | 12:04 AM

geargrinder

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From: Omaha Nebraska

RE: Cross over exhaust Pipes ..Why ?

Because an exhaust equalizer provides a broader power band on dual exhaust systems.

Apr 17, 2007 | 12:50 AM

wesd41

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From: Winslow, Arizona

RE: Cross over exhaust Pipes ..Why ?

What geargrinder said, plus this- the only reason HD puts a left side muffler on the bike at all is so it looks balanced.

Apr 17, 2007 | 12:57 AM

Retired_Ted

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RE: Cross over exhaust Pipes ..Why ?

A crossover system provides a scavenging effect in that the exhaust from one cylinder provides some momentum in the exhaust system to help clear out the second cylinder - best example is a 2 into 1 system - they have the best dyno figures for our engines. By disabling the crossover system, we cut our power potential - most don't mind the power loss.

Apr 17, 2007 | 06:06 AM

RBJones

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From: East Tennessee

RE: Cross over exhaust Pipes ..Why ?

Quote:

ORIGINAL: Retired_Ted

A crossover system provides a scavenging effect in that the exhaust from one cyclinder provides some momentum in the exhaust system to help clear out the second cylinder - best example is a 2 into 1 system - they have the best dyno figures for our engines. By disabling the crossover system, we cut our power potential - most don't mind the power loss.

Good explanation. True duals do look good and eliminating the crossover is nice. I think true duals can probably have as much power as anything else, but only at certain points along the power band. The misbalance between the pipes due to their different lengths is going to cause flat spots and dips along the torque and power curves regardless of what you do and you have relatively little control even by changing efi MAPs. You can't fight the laws of exhaust physics. But they do look good and if you've got wads of power to spare anyway, you're probably going to be very happy with them.

Apr 17, 2007 | 10:06 AM

HogBack

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From: Snowflake, Arizona

RE: Cross over exhaust Pipes ..Why ?

As the others said, the scavenging benefits are a real plus. Take for example the headers on a V-8, on a high performance application where they run WITHOUT the crossover muffler exhaust system, they get the important scavanging for the four cylinders on each cylinder bank with each header. Dynos show that an even better benefit is an equal length header tube design. A 2 into 1 is based on the header principal. IMO a crossover is a very good design to stay with when you go with an aftermarket dual exhaust.

Hogback