At Clear Image Automotive our approach to header design differs from other manufacturers and fabricators. Throughout the industry, the terms "equal length" and "tuned" are used in header marketing.
Ideally, we agree a perfectly designed header should be equal length. However, because most customers are purchasing headers for their every day street cars and trucks, the header design must allow for clearance around accessories such as the air conditioning compressor and lines, ABS and brake lines, factory installed emissions systems, decorative engine covers, etc.
The header must also be able to be installed and removed without having to cut or modify OEM components and plenty of clearance must be provided for spark plugs and wires. With these requirements in mind, the header design must allow for an increase in exhaust flow (scavenging) in order to increase efficiency of the engine.
An efficient performing engine will produce more power, create less pollutants and increase fuel economy. In order to design an equal length header in such a tight engine bay, some manufacturers will add bends and turns to lengthen the primary tubes. This requires some rediculous tube routing which often resembles Chinese noodles.
The resulting headers may indeed be equal length or tuned, but exhaust flow is inhibited dramatically due to the design. Every time a bend or a turn is added to the design, friction is created and the exhaust flow slows down. In some cases where headers have been designed with so many bends, an exhaust restriction can occur which causes back pressure.
We take a much simpler approach to header design. As in our high performance exhaust systems, we minimize the amount of bends whenever possible to achieve point A to point B routing. The most efficient path between two points is always a straight line. Obviously it is virtually impossible to design headers, or exhaust systems, with no bends.
But by utilizing this point A to point B approach, exhaust flow (scavenging) is kept as efficient as possible yielding the highest power and fuel economy. Our approach to header design also has the benefit of cooler under-hood temperatures. Other manufacturers often have problems with their headers melting accessories.