No matter the exhaust header length in a car, the choice of a length matches the specific needs of the car. While short lengths, for example, are easier to install, long lengths are more difficult to install but best for high performance. If you know the Engine Cubic Inch Displacement, the Engine Maximum Revolutions Per Minute, and the Header Tube Outside Diameter , you can use the Bowling's Best Exhaust Header Predictor equation to determine the best exhaust header tube length for your car engine.

- Skill level:
- Easy

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### Things you need

- Calculator

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## Instructions

- 1
Define the parameters you will need. The equation you will use states that Exhaust Header Length (H) in inches equals Engine Cubic Inch Displacement (CID) in inches times 1900 divide by Engine Maximum Revolutions Per Minute (RPM) in revolutions per minute divide by Header Tube Outside Diameter (OD) in inches. Therefore, you will need three parameters: "CID", "RPM", and "OD".

- 2
Simplify the calculation. Calculate "CID" times 1900 with the aid of a calculator to obtain a single value, which we will call the numerator. Calculate "RPM" times "OD" with the aid of a calculator to obtain a single value, which we will call the denominator.

- 3
Perform the calculation. Calculate the numerator divide by the denominator with the aid of a calculator to obtain "H".

#### Tips and warnings

- Long engine pipe length is an important component in achieving maximum power, for example, when optimising the performance of an engine for racing.
- Short pipes and long pipes have both advantages and disadvantages; the decision to use an exhaust pipe length is up to you.