Triumphrat

SCCTrim

Recently I attended a local small bike show, there was a dyno present...( and primarily Harleys )...and a couple guy's made some pull's on their bikes. One in particular was a Fatboy with "Torque tubes" installed. This thing pulled like hell. 124 lb ft of torque, and something like 67 horses.

I was curious if anyone make's them for the smaller exhaust on bonnies?

Opinions?

SC

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rodburner

Is that the same as "power cones" anti-reversion inserts? If so,they are in the J&Pcycles Harley catalog. :???:

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SCCTrim

Not certain if it's the same or not....I have never seen them myself in person. Will have a look around....

I don't think these are the same items. I was under the assumption that this was something that inserted into the header and had a flat piece of metal inside...as if to create a small chamber in the "tube"


.....maybe I'm wrong

SC



[ This message was edited by: SCCTrim on 2006-06-24 20:13 ]

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SCCTrim

Turn's out they are actually "Torque Cones"

Inserted @ the head end of the pipe, apparently they create a slight amount of back pressure for the harleys.

I read a article yesterday eve. about exhaust and the science behind it, very technical...

SC

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dazco

I made some of those about 6 months ago in hopes of lowering volume. Didn't work too well. Lowered volume along with power.

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Scrambler900

Another term for them would be "reversion tubes", or, venturi. White Brothers is a firm that makes a slip-on set for open drag pipes, as can be found on Harley's. They function by adding some "back pressure" to the exhaust.

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SCCTrim

What I read was very informative....there was mention of gas velocity, and other stuff I cannot presently remember.

In short, my take of it was that it would need to be engineered for my bike.

...lot's of testing

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raproe

Weird engine. 124 lb-ft of torque and only 67 horses. Since Horsepower=Torque*RPM/5252 the torque must fall off like crazy at higher RPMs. I would expect well over 100 HP from an engine having a peak torque of 124 lb-ft.

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Pete_Twizz

As I understand, these items are used to compensate for aftermarket pipes which don't create enough back pressure. There is a tendency, particularly among the HD fraternity, to go for large bore exhaust systems for their appearance. The misfiring and backfiring of bikes equipped with such pipes suggests that the design did not take into account gas velocities or the resultant pressure changes.
In short, torque cones (or tubes) are a fix for poorly designed exhaust systems.

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sweatmachine

Those numbers are suspect at best.

The device you're talking about, torque tubes/cones/backpressure cones, etc is to give the proper amount of back pressure in really short pipes.

You know those short pipes on the TV shows, that are really loud? There's no way they make enough back pressure for those engines to run correctly, so they machine these little cones that drop in the header pipe at the exhaust port.

They restrict the flow enough to act like the pipes are longer, making it possible to run short pipes and still have adequate backpressure.

It's not really a performance mod, it's more like a rig-job to fix the pipes that really don't work right.

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