[V8Vairs] Oops... Shoulda changed subject line to Project Update...

[Rick & Janet Norris]

Doug,
Strange is in the mind of the beholder! It will be very interesting to hear 
the exhaust note from that instrument. My guess is the four smaller pipes 
will have a rack of their own.
Rick


>I don't know if there was as much 'reasoning' behind it as there was
> desperation.  Since the drive train and the live rear axle take up all
> available space to the rear of the engine compartment, I had no choice but
> to run the headers forward.  Design is based on the numbers generated by
> the HeaderDesign program, but have been somewhat perverted due to space
> constraints.  By running the headers forward, the muffler location had to
> be under the seats.  Little ground clearance exists at that point, so the
> muffler and any attached tubing had to very thin.  The finished muffler is
> only 2-1/8" thick.  I didn't have room for a conventional round collector,
> and so had to arrange the primary pipes in a flat configuration.  That, in
> turn, forced the use of a tapered flat collector.  For ease of
> installation/removal, I flanged the primary to collector joint rather than
> the more usual post-collector flange location.  There are a few flat
> mufflers on the market, but I couldn't afford them or the extensive number
> of oval pipe bends and straights that would be needed, so I chose to build
> my own muffler.  It has internal ducting to marry the banks together like
> an X fitting.  Since the incoming and outgoing exhaust paths are parallel
> and in a counterflow arrangement, I made the gas duct walls out of
> perforated sheet so that the pressure pulses will hopefully bleed across
> and create multipath averaging of the pressure waves.  Outside radii of
> the internal ducting is solid sheet to get the gas going in the proper
> directions.  The flow path looks like it will work pretty well, but only
> time and engine start will determine if it actually does any muffling. The
> quad outlet pipes were chosen for two reasons; the pair of smaller pipes
> provides more ground clearance than a larger pipe with the same flow, and
> since the outlet size is supposed to be 50% of the total primary tube
> area, using four of the same sized pipe works exactly.  The primaries are
> 1-3/4" by 36" and the collectors equivalent to 3" by 16" long.  Should be
> about right for the warmed over 500.  The exhaust outlets dump just in
> front of the rear wheels.
>
> The engine cover and air cleaner housing is designed to pull fresh air
> from the Corvair cooling air plenum though a 3" by 16" duct which rides on
> an aluminium plate bolted to the carb.  That plate also served as the base
> for the air cleaner element and so obviously must float with the engine.
> The engine cover has a lip inside to attach an air seal to isolate engine
> compartment air, and bubbles up to clear the element.  The transverse
> bulkhead and the three part engine cover also serve as the firewall.
> Strange what we get ourselves into, isn't it?
>
> Doug Evans
> '67 Coupe with very little remaining stock
>
>
>
>
>
> "Rick & Janet Norris"
> Sent by: v8vairs-bounces at corvair.org
> 03/28/2005 04:32 PM
> Please respond to
> v8vairs at corvair.org
>
>
> To
> <v8vairs at corvair.org>
> cc
>
> Subject
> Re: [V8Vairs] Front Wheel Size Capability...
>
>
>
>
>
>
> Doug,
> That's a neat exhaust system. What's the reasoning behind it?
> Rick Norris
>
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