🚀 go-pugleaf

In article <1992Nov7.194728.27568@ee.ubc.ca> kenb@ee.ubc.ca (Ken Buckland) writes:
>vanderby@mprgate.mpr.ca (David Vanderbyl) writes:
>> jmorriso@ee.ubc.ca (John Paul Morrison) writes (and draws a fancy picture):
>> > vanderby@mprgate.mpr.ca (David Vanderbyl) writes:
>> > >(This, incidentally, is why a hole in your muffler cannot help
>> > > you pass emissions testing.)
>> > 
>> > Depending on the shape of the hole, and its position, the exhaust gases
>> > could easily, and conceivably create a vacuum, and suck in more air into
>> > the hole, thus diluting the exhaust.
>> 
>> As to this vacuum theory, yes it is conceivable that fresh air may enter
>> the system.  However, it is extremely unlikely since the muffle/tailpipe
>> create a back pressure in the system.  This is why air pumps are necessary
>> for air injection anti-pollution systems, and the engineers who designed
>> the car cannot simply strategically place a well shaped hole to achieve
>> the desired effect.
>
>I was assured by three different muffler technicians (all from reputable
>muffler institutes) that exhaust system holes *do* suck air into the
>exhaust.  This might be due to a vortex effect - I don't know.  Further,

That seems to settle it. Here on the net we've had theoretical conjecture
and argument, then the muffler shop confirms with empirical evidence.

The scientific process goes on. SO it follows that we should now all
put in for NRC grants, write a paper, take on grad students, neglect
teaching, and then sit back doing nothing. :-)

>
>Ken Buckland
>kenb@ee.ubc.ca
>

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 John Paul Morrison                     |  
 University of British Columbia, Canada |  
 Electrical Engineering                 |   .sig file without a cause
 jmorriso@ee.ubc.ca              VE7JPM |  
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