[aerohead]

Originally Posted by JulianEdgar

The nearest parallel I can think to all of this is the old argument about engines 'needing back-pressure'.

I used to have this argument all the time, especially with older modifiers, about 20 years ago. They, too, would quote outdated magazine articles, outdated books, etc. Then they'd tell me the results of their tests - how power went down with free-flow exhausts. They had all sorts of theories as to why back-pressure was needed, and what terrible things would happen without enough back-pressure.

And, unfortunately, some people modifying their cars listened and were terrified of putting on large exhausts and freeflow mufflers.

I very much doubt 'engines needing back-pressure' was ever a valid concept, and with the advent of engine management and the ability to tune an engine so much more finely than with points and carbies, it is of course now just rubbish. But to this day, some people believe it.

That's why I hate seeing BS being spread in car modification - unless it is challenged, it gets a life of its own. And I really like seeing people succeed, not following bad advice and so going on to achieve substandard outcomes.

Back issues of HOT ROD Magazine are your friend.They have published for decades on this topic and have the controlled,laboratory,engine test-cell, dynamometer data to back up all the dialogue.