How to Build a Custom Exhaust System

The majority of factory exhaust systems are hefty, restricted, and, to make matters worse, quiet. Not to add that stock exhaust manifolds are rarely compatible with your hot rod’s chassis or engine compartment. You don’t want to put that brand new crate engine in your project and try to utilize the factory exhaust pieces that came with it, do you? Even if your crate engine does not come with exhaust headers, you will need to figure out how to transfer your wasted exhaust gases from the engine to the rear of your vehicle. This article includes a quick explanation of everything you’ll need to build your hot rod’s new exhaust system, as well as links to additional content to assist you in making your decision.

How to build custom exhaust system.

Where Should You Begin When Designing Your Exhaust System?

It makes sense to begin at the beginning and work our way back, doesn’t it? In that scenario, headers are the way to go! Almost all stock manifolds are cast iron, and casting fragments can be found in the exhaust pipe. This creates turbulence and restricts movement. The majority of approximately 800 different styles are tubular steel designs, ensuring optimum flow with minimal interruption. Some are long, some are short, and some are in the middle of the dump. It all relies on your application and personal preference. Most stock applications around 350ci can benefit from a 1-5/8-inch primary tube header, however, a greater power application will necessarily require a larger tube, ranging from 1-3/4- to 1-7/8-inch. There are custom manifolds such as LS swap cast iron turbo applications, and much more!

Tight-Fit Block Hugger Headers for Small Block Fords

We have made it abundantly obvious that you have numerous options for headers. However, we are not attempting to muddy the waters here, but rather to make you aware of the several possibilities available, such as primary tube size, short or long tube header length, coated or painted (or bare!), fully welded or kit form, and much more. Any exhaust header buyer’s guide should be your first port of call when it comes to configuring your hot rod’s new exhaust system.

What Exhaust Pipe Size Should I Use?

The classic rule of thumb that for every 100 horsepower, 1 inch of total pipe diameter is required across the system is a quick and easy approach to determine what diameter pipe you will need from the headers to the mufflers. A 500-horsepower engine, for example, would necessitate a 5-inch exhaust pipe (divided into the dual exhaust, which means a 2-1/2-inch diameter pipe for each engine bank). This is, of course, a rough approximation, and there are various complex mathematical formulas available to assist you in determining the “ideal” size pipe to employ for your hot rod project. There are also various online calculators available, such as this one. Simply enter your engine’s horsepower figure and the number of exhaust pipes you’re running to the back of the car, then click “calculate.” The calculator will perform the calculations for you and provide you with the minimum acceptable pipe diameter for your application. Then you can browse exhaust pipe kits and add the system to your shopping basket. You may also learn more about exhaust pipe sizing by reading an exhaust pipe sizing toolbox guide.

How Do I Decide Which Mufflers to Buy?

Your choice of mufflers should be based on performance as well as sound. Do you prefer a deep growl or waking up the neighbors on a Sunday? There are several options available to you.