After a previous post on exhaust back pressure, I’ve been watching in pit lane for how different manufacturers approach the challenge of designing an exhaust solution that maximizes engine performance.

Each solution depends on the engine layout, of course. The Yamaha YZR M1 has an inline 4-cylinder engine, so each exhaust port is adjacent to the others at the front of the engine, as opposed to a V-4 design where two ports are at the front and two at the rear.

With Yamaha’s inline 4, the exhaust pipes follow a 4 into 2 into 1 design. In this image you can see how two of the pipes join into one just below the engine block and beneath that, the other two join into a different pipe as the exhaust gases are directed toward the rear of the engine.

Now that there are two pipes instead of four, they are routed around the oil sump. The image atop this post shows the right side of this section. (Click on the top image to see a larger version.) The topmost image also shows the two pipes joining into one. The final section of single pipe is pretty short. It ends in an aerodynamic grilled opening that is much different from previous designs.

Up until Catalunya 2014, the pipe sported a traditional silencer like this and you can see that this exhaust design used a much longer section of single pipe.

After Catalunya the silencer design changed to this non-round shape. The single pipe section grew shorter, but there still appeared to be some silencing going on based on the thickness of the final section of the pipe.

The current design looks like this and similar to Honda’s pipe ends, does not appear to have any silencing properties as in previous versions.

As we will see in coming posts, exhaust designs can be radically different based on engine layout and the ideas of the engine designers.

Photographs: ©2014-15 by Scott Jones / PHOTO.GP – All Rights Reserved

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