Your membership to HeaderDesign.com will give you everything you need to design header-based exhaust systems for 4-stroke, naturally aspirated gasoline engines. At the heart of HeaderDesign.com is the Header Design Program. This program is the result of years of research in exhaust system gas dynamics and the interaction of headers with other engine systems.

The Header Design Program uses basic engine specifications (such as horsepower, peak horsepower RPM, compression ratio, bore and stroke) combined with intended use information to calculate header and collector pipe sizes and lengths. Use the program output as a guideline for buying, modifying, or scratch building a set of headers.

HeaderDesign.com members get their headers sized right on the first try. Use the Header Design Program to:

• Design custom headers that match your exact engine and operating RPM range.
• Calculate the optimal diameter and length of your primary header pipes. When considering the purchase of off-the-shelf headers, you must know the best primary header pipe size.
• Calculate the optimal collector diameter and length needed to work with your primary header pipes. Only the proper size collector will provide optimal scavenging and best engine performance. Headers you buy or already own can easily be modified to accept the right size collector.

HeaderDesign.com members also benefit from the following valuable tools and information. These include:

• Extensive information on selecting, building or modifying a set of headers
• Sophisticated advice on properly locating an X-pipe, Y-pipe, or H-pipe
• Guidance for selecting the proper diameter tailpipes
• An Exhaust Pipe Selection Guide
• A CFM Calculator that determines the proper size carburetor or throttle body for a particular engine and application

We plan to add valuable services in the future. Check back often to see what new features we have added to HeaderDesign.com.

While the Header Design Program addresses the vast majority of four-stroke, naturally aspirated, gasoline engines, there are some practical limits to its application. They are:

• Bore sizes can range from 2.800in. to 4.625in.
• Stroke length can range from 2.400in. to 5.250in.
• Bore to stroke ratio can range from 0.80 to 1.42
• Compression ratio can range from 7-to-1 to 16-to-1
• RPM at maximum horsepower can range from 2500 to 10500
• One header pipe per cylinder
• Collected header designed for independence

The Header Design Program adds significant value to many popular engine simulation products. These products can be used to provide sufficiently accurate performance estimates for the Header Design Program. In turn, many of these products assume you are using an ideally sized header exhaust system, which is what the Header Design Program produces. Use these products together with your HeaderDesign.com membership to plan for optimal engine performance.