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Common Definitions for an Exhaust Fabricator SHop

Centerline Radius
On bends, this refers to the radius used to create the bend. The smaller the radius is, the “tighter” the bend. It is difficult to physically measure on anything but a U-Bend (180 degree bend). It is measured from the center point of one leg to the center of the other leg and divided by two. An easier way to measure is from the outside of one leg to the inside of the opposing leg. Remember that if the bend isn’t exactly 180 degrees it will affect your measurement.

Conical Length
Conical length is also the height, measured down the centerline of the cone. Conical length is not affected by taper of the cone.

For stock items, dimensions are stated in inches. The point they are measured from is stated in the specifications for that product. This link is to a popular conversion calculator.

Included Angle
The entire angle that contains the taper. Included angle is two times the taper.

For cones, inlet generally refers to the smaller end of the cone. On collectors, the inlet is where the header pipes come into the collector.

Inside Diameter (ID)
Measured across the inside of the diameter. ID will vary from OD based on thickness of the material. It is equal to the outside diameter MINUS twice the material thickness. Typically you need to know an ID when you want one part to fit INSIDE another part. Cone Engineering designs components utilizing an ID with a fitment factor to allow room to insert the OD of the other part. For example, a flange for 1.50” OD tubing will be slightly oversized to allow insertion without additional fabrication.

Material Thickness (also Wall Thickness in tubing)
Measured in decimal or gauge (also gage). We generally use gauge as the decimal equivalent can be slightly different based on different measurement factors. Several good reference sources are available on the internet to assist in converting from one basis to another. Here is a link to a favorite web-based conversion chart.

Outlet generally refers to the larger end of the cone or on collectors, refers to the exit end of the collector.

Outside Diameter (OD)
Measured across the outside of the diameter. It is also equal to the inside diameter PLUS twice the material thickness. Use this when you want one part to slip OVER another part or if you will be butt welding two parts together.

Side Length
Length of the cone measured down its side. Side length is affected by the taper of the cone. The greater the taper the larger the differential between the side length and conical length.

Taper (also known as “occluded angle”)
Taper is half the included angle of the cone. It is expressed in degrees and measured from vertical to each side of the cone. Each edge of the taper forms a leg of the angle which is a right angle. Click here for a Cone Calculator >> Cone Calculator to determine taper based on your desired cone dimensions.

The “Right Size” Exhaust for Your Car or Motorcycle
Size does matter when it comes to exhaust in cars and motorcycles but bigger isn’t always better. Determining the correct size is as much art as it is science. Many exhaust fabricators have a wide variety of sizes they recommend to suit a particular application of which engine displacement is just one factor. Cone Engineering gives you a wide array of options so that you can fabricate the exhaust you feel best suits your needs. Our stock parts are designed to offer flow characteristics suited to a broad range of uses. They can further be customized by the end-user with simple modification.



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