H pipe, X pipe and Y pipe Application Primer
07-06-05, 09:59 AM
#1
Lexus Champion
Thread Starter
H pipe, X pipe and Y pipe Application Primer
There has been much discussion on the header thread and elsewhere regarding X pipes, Y pipes and H pipes. I am starting this thread to discuss the pros and cons of each.
Headers make more power over a broader RPM range when the individual pipes are joined together with a collector. The same phenomena occurs with the secondary exhaust. There are three "categories" of "joining" the 2 secondary pipes (the 2 pipes from each exhaust manifold).
H pipe, Y pipe and X pipe.
Among these "categories" are several design variances.
H pipes are fairly consistant with a single crossover pipe going between the 2 main pipes generally at a 90 degree angle. This pipe does not carry much of any flow from side to side. It works by giving the accoustic energy an expansion area. Lowering the accoustic energy enhances flow and allows the engine to generate more torque and power. Placement of the crossover effects the performance.
X pipes come in 3 styles. The most common style is what I will refere to as a "window" X pipe. This style basically keeps both feed pipes the same size. These pipes are bent to touch each other, a small opening is cut in each pipe where they touch and they are welded together creating a window between them. Since the pipe size is barely effected by this window most of the flow stays in the side it starts in. The window works like the H pipe and allows the accoustic energy to expand. The shapes created are different than an H pipe so it sounds different but the effect is similar.
The next common style X pipe I will call the "plenum" style. This is the style that Bassani makes. The plenum combines and slows the flow. This allows the accoustic energy to expand but also slows the flow. I do not recommend this style.
The least common is the "merge" X pipe. The pipes actually form an X. Sizing and design is very important here but if done properly it is the BEST style X pipe. A merge X pipe works like a racing merge collector. It uses the heat energy, inertia energy and accoustic energy to accelerate the flow through the merge. If designed properly this acceleration allows the engine to make the most power over the broadest RPM range.
Y pipes work like a merge X pipes. Again, as with the X pipe, design and execution are very important to maximize a Y pipes power enhancement. A well designed window X pipe can outperform a poorly designed merge X or Y pipe.
Headers make more power over a broader RPM range when the individual pipes are joined together with a collector. The same phenomena occurs with the secondary exhaust. There are three "categories" of "joining" the 2 secondary pipes (the 2 pipes from each exhaust manifold).
H pipe, Y pipe and X pipe.
Among these "categories" are several design variances.
H pipes are fairly consistant with a single crossover pipe going between the 2 main pipes generally at a 90 degree angle. This pipe does not carry much of any flow from side to side. It works by giving the accoustic energy an expansion area. Lowering the accoustic energy enhances flow and allows the engine to generate more torque and power. Placement of the crossover effects the performance.
X pipes come in 3 styles. The most common style is what I will refere to as a "window" X pipe. This style basically keeps both feed pipes the same size. These pipes are bent to touch each other, a small opening is cut in each pipe where they touch and they are welded together creating a window between them. Since the pipe size is barely effected by this window most of the flow stays in the side it starts in. The window works like the H pipe and allows the accoustic energy to expand. The shapes created are different than an H pipe so it sounds different but the effect is similar.
The next common style X pipe I will call the "plenum" style. This is the style that Bassani makes. The plenum combines and slows the flow. This allows the accoustic energy to expand but also slows the flow. I do not recommend this style.
The least common is the "merge" X pipe. The pipes actually form an X. Sizing and design is very important here but if done properly it is the BEST style X pipe. A merge X pipe works like a racing merge collector. It uses the heat energy, inertia energy and accoustic energy to accelerate the flow through the merge. If designed properly this acceleration allows the engine to make the most power over the broadest RPM range.
Y pipes work like a merge X pipes. Again, as with the X pipe, design and execution are very important to maximize a Y pipes power enhancement. A well designed window X pipe can outperform a poorly designed merge X or Y pipe.
07-29-05, 08:06 PM
#6
Lexus Champion
Thread Starter
Originally Posted by Hollywood
But all out cat backs come as y style, are we really going to make effective use of an x pipe befor our y style cat backs?
Here is a properly designed Y pipe section:
Notice the narrown angle that the pipes merge together.
Notice the minimum collector volume.
Notice the diameter after the merge is relatively small and then expands up to the desired exit pipe diameter.
BTW, this is TOP END stuff from Burns Stainless. Cost on this 2-into1merge is over $250.
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