Exhaust pipe sizing -Ensure compatibility -Ⅰ

We are going to discuss exhaust pipe sizing.

When building a custom exhaust system out of miscellaneous components, it is important to understand how the industry sizes different components that are going to be necessary to build that system. Exhaust piping, mufflers, collector reducers all are going to be sized differently from one another to ensure compatibility and to make sure they mate up with one another.

What we are going to discuss is the difference between the measurement of these items when it comes to OD in comparison to ID and what components are going to go ahead and fit together with one another as an end result.

The first component we are going to discuss in building one of these systems is exhaust piping. Most exhaust flexible pipe is going to be measured using OD dimensions which is outer dimensions of exhaust flexible pipe or the outer diameter. That means if you were to purchase a three-inch pipe—let’s say like the one we have here—the outside diameter of exhaust flexible pipe would actually be three inches. This creates a situation where exhaust flex pipe is designed to be a slip fit or slip into a component that has a three-inch inner diameter.

That will essentially create what is known as a lap joint between those two components where one fits within the other component. This is important to understand because sometimes you have to connect one pipe to another, say from a collector reducer over to the pipe itself. This creates a situation now where the two items cannot actually be slipped in one another and it makes it not possible to have that lap joint like we mentioned. This is known as a butt joint. Exhaust system components such as mufflers and exhaust tips normally use inner-diameter dimensions on the piping used to build these components. Most of the time, this does create a lap joint fit when it comes to connecting this pipes to these components in the system.

The most common type of connection when connecting a piece of exhaust piping to a component such as a muffler is what is commonly known as a lap joint connection, which essentially means that we are going to be able to insert the pipe into the component as shown here.

This type of connection is probably easiest to deal with as well because you can typically take a standard saddle clamp or the proper band clamp and get these two connected to one another, or you can just weld the seam between the two for a leak-free fit. These will always have some measurable leakage though if using a clamp to connect the two, because what will happen is you will always have that seam between the two components that is going to give it the ability to have just a small amount of leakage between the two.

To be continued……..