Short and sweet...

Read the book.

Editorial Review:
Book Description
This is one of the best-selling technical books in its field. For years,
engineers, engine designers, high-performance tuners and racers have
depended on this book to help maximize their engines' potential. Dr.
John C. Morrison is one of the foremost authorities on the analysis of
the induction and exhaust processes of high-speed engines. Together with
Philip Smith, he gives a thorough explanation of the physics that govern
the behavior of gases as they pass through an engine, and the theories
and practical research methods used in designing more efficient
induction manifolds and exhaust systems, for both competition and street
use.

Published by: (you guessed it!) Robert Bentley Publishers.

Available at Amazon for twenty bucks. If you live in a big city, the
library probably has it.

Jim

Jack wrote:
> The experts will correct - but I think a point being slid over too
> casually is that a race engine is really a different animal.  A clue is in
> the word "harmonics"; that's related to engine speed.  Race engines are
> designed to produce power over a much narrower range of RPM than is the
> street engine.  So, "tuning" the exhaust to those speeds is relevant.  The
> street engine is a huge compromise as it tries to deliver useable torque
> over a much larger range of RPM.  "Tuning" the exhaust is no longer
> particularly relevant.  So, again, it's apples & oranges.  That's not to
> say the exhaust can't be poorly designed for any application!
>
> //Jack
>
> On 31 Aug 2002, at 20:57, Jim Arnott wrote:
>
>
>>And Phillip K. Smith's "The Scientific Design of Exhaust and Intake
>>Systems" will tell you exactly how to select the proper diameters and
>>lengths. All you need to know it the displacement of the cylinder, the
>>cam timing, where you want the power to occur and a few other easily
>>calculatable data points from you engine and you can build something
>>*much* better than anything you can buy.
>>
>>Jim
>>
>>Kim Brennan wrote:
>>
>>>In a message dated 8/31/02 6:28:18 AM, clive.harman-smith@NTLWORLD.COM
>>>writes:
>>
>>>The wrong length pipe can cause a standing pressure wave in the exhaust
>>>system, this means that is is harder for the engine to get the burnt fuel out
>>>of the pistons, and causes a loss of power. Block your exhaust pipe and
>>>you'll see what I mean. If the exhaust can't get out, the engine won't run
>>>for very long. ON the other paw, if you have just the right length, the
>>>exhaust system acts as a partial vacuum and actually aids in removing the
>>>spent fuel from the pistons.
>>>
>>>Why? Harmonics. You have pulses being caused by the pistons. These occur
>>>rhythmicly and as with any other rhytmic system, you can get reinforcement of
>>>the waves in a positive or negative fashion. In this case the waves are
>>>pressure points in exhaust gases. High pressure is a positive reinforcement,
>>>low pressure is a negative reinforcement.
>>
>
> .
>