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re: TR 4 cylinder intake/exhaust manifolds

To: "INTERNET:CarlSereda@aol.com" <CarlSereda@aol.com>
Subject: re: TR 4 cylinder intake/exhaust manifolds
From: Dave Massey <105671.471@compuserve.com>
Date: Thu, 9 May 2002 09:30:56 -0400
Cc: "[unknown]" <triumphs@autox.team.net>
Message text written by INTERNET:CarlSereda@aol.com
>Darrell
The connection provides heat transfer to the manifold tube dividers in the 
intakes. When your gas/air mixture hits the 'hot V' it atomizes the mixture

minimizing liquid drops of fuel and improves combustion. Notice older cars 
use this exhaust connection too and newer cars get their heat from the 
thermostatic controlled coolant - that's piped through the manifolding.
Without it you might experience innefficient combustion and 'icing' (ice 
buildup) on manifolds due to rush of cool air going through system. I
believe 
physical support was a secondary benefit.

Carl  - '63 TR4

The intake and exhaust manifolds (I think on all 4 cylinder TRs, but
certainly on the 4A) are attached to each other with two studs.  I'm not
sure what function that is supposed to provide, other than to possibly help
support the intake manifold.  But it also seems that it would provide quite
a good heat transfer, something that seems less that ideal.  Given that
none
of the headers offered appear to provide this support, and that I haven't
heard of any rash of intake manifolds falling off, I'm considering removing
the bracketry where these two attach.  Any reason I shouldn't do that? 
Darrell Walker
66 TR4A IRS
<

Carl's description explains it pretty well.  I would just like to add that
the fuel precipitation only occurs at low flow rates (idle).  Under way,
the air flow rate is high enough that the fuel does not have a chance to
form droplets and fall to the bottom of the manifold.  The flow rate is
also high enough that heat transfer to the intake mixture is negligible so
this has no effect on available horsepower.  It only improves the idle on
an engine whilst it is warming up.

Dave

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