Header Technology

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Today, advanced engine technology has helped the two-valve competition engine reach over 2.5 horsepower per cubic inch. Camshaft design and cylinder head technology has led the way to competition engines that easily spin well over 10,000 rpm. Current competition header technology is designed to actually pull air through (scavenge) the engine, using smaller primary tubes and properly sized merged collectors.

There are many factors that can help contribute to the performance of the competition engine. Overlap in the camshaft design plays an important role in how the header affects the characteristics of the competition engine. Today modern cylinder head design has led to less need for excessive overlap designed into the camshaft due to high flowing smaller intake ports. The current header technology now has an important role to help your competition engine reach its maximum efficiency.

Smaller primary tubes are used to keep the exhaust speed high in the header, which in turn, on overlap this exhaust speed is used to pull the air through the engine. Current header technology has proven that bigger is not always better on today's competition engine. Dyno results and track testing has shown that usually the best header combination is using the smallest size primary tube and merged collector throat. Track and Dyno testing has shown that you can literally choke a motor off by using too small of a header, and further testing has shown that you can hurt power and acceleration by using too large a header as well.

Primary tube size can be dictated by several factors in the modern competition engine. The engine cid, usable rpm, exhaust valve and port size, and horsepower of the engine are used to help determine the sizing of the header primary tube, length, and merged collector throat. Other important factors to consider in header design are the weight of the vehicle, where the engine is actually pulled down to on the shifts and how high the engine is spun at the finish. Consideration must be taken that a heavier vehicle will spend more time in the lower rpm range than a lighter vehicle, as will a race car with only a two speed transmission compared to a five speed clutch car. Primary tube length needs to be adjusted accordingly, as a shorter primary tubes tend to make more power in the higher rpm range and the longer tube is more powerful in the lower rpm range.

The merged collector is designed to pull air through (scavenge) the modern competition engine. The exhaust speed is kept very high in the collector, which in turn keeps the air moving through the primary tubes and literally sucks the air into the engine on overlap. This helps create the volumetric efficiency necessary to achieve the power results of today's competition engine. The merged throat size is mathematically determined using the primary tube size and horsepower of the engine, then can be slightly adjusted by using other factors in your racecars performance. As with the primary tube size you can literally choke an engine off using too small of a merged collector throat, and using to large of a throat slows the exhaust speed down in the collector, pulling less air through the competition engine.

Designing the competition header for today's modern race engine can throw the engine builder and the header fabricator for many curves. Each competition engine has its own inherit characteristics and when trying to reach the maximum potential, sometimes excessive trial and error is necessary with carburetion, camshaft, headers and many other components. Performance Welding Racing Headers has done extensive trial and error with many top competition engine builders to build you a competition header for maximum efficiency. Our competition headers are built using the widest radius tubing available creating a very smooth flowing primary tube for maximum power. Our merged collectors are mathematically sized along with extensive trial and error to create a header that will pull air (scavenge) through the competition race engine. Our craftsmanship, product quality, and attention to detail are absolutely second to none. Our competition headers have proven to be successful in NHRA drag racing, Bonneville, Winston West, Turbo, Nitrous, and Street applications.

Understanding today's competition header technology includes understanding today's modern competition racing engines. Performance Welding Racing Headers is constantly building competition headers in the four into one and Tri-Y design for our research and development program. We work closely with top competition engine builders, receiving header characteristic data on the dyno and racetrack, advising and receiving advice on future header designs to provide the fastest accelerating competition racing header in the industry.

- Mark Lelchook / Owner
mark@performanceweldingheaders.com