Quote:
Originally Posted by Old Tele man
Obviously, 108" header pipes are both impractical and physically too long to fit, but the "longer-is-better" approach could be compromised to "fit" by making them as long as practically possible, and then transitioning directly from the header pipes directly into the obligatory muffler...thus eliminating more piping.
What engine RPM do you want the pipes to "tune" to? I don't know where the torque peak is for the that engine...I just guessed at 2,000 RPM for highway cruising.
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One of the things to know about header design is that due to packaging concerns, headers are often shorter than they need to be. This is not as bad as it sounds because the pulses traveling down the tube reflect off the "open" end at the collector and again at the closed valve. So, if you find that you "need" a length of 108", a length of 54" will also have good effect at your chosen RPM (and at double that RPM as well of course.) If you can make the length of the "midpipe" from the collector to the muffler that same 54", that will help to reinforce the pulses at your chosen RPM as well.
Additionally, the idea of running individual pipes with their own mufflers will also be disadvantageous. Having them come together in a collector will let the pulses from the other two cylinders affect the cylinder that is in it's exhaust stroke. As the other cylinders are operating 120* off of the cylinder in question, the effects come in at different RPM but they do help to balance out the entire torque (and therefore FE) curve of the motor.