<VV> Elec fuel pump

[Joel McGregor]

I thought we were talking about what passes for standard pump gasoline not just some random substance.  Last time I checked vapor lock happens as a result of a hot soak when the fan isn't running.  The lines between the carbs and pump have a direct heat path to the engine and only one end of the inlet line does.  The inlet line is also mostly just above tin where the lines to the carbs run above the heads.  I would agree that the air temp they are exposed to will be the same but the radiant heat will likely be higher.  The higher volume of the inlet line will also require more heat to bring the fuel up to the same temp as the lines between the pump and carbs -again because the problem is created when it's not running.  I haven't done the math to see what the linear flow rate comparison would be between the larger inlet line and the smaller outlet lines but I would guess that it's pretty similar since the inlet is flowing 2x a single outlet.  While running the inlet line should stay considerably cooler.  It has the coolest fuel coming into it which gradually warms up and then is heated more by the pump and then even more as it flows through the outlet tubes.  So as soon as fuel starts to flow the fuel in the outlet lines will be hotter than the hottest fuel in the inlet line so even if they were exposed to exactly the same about of ambient and radiant heat the fuel in the outlet tubes will be hotter than what's in the inlet tube.
You've got me curious now.  I need to take some temp measurements sometime.
Do you know of a chart on the internet that shows the point pump fuel vaporizes at various temps and pressures?

Joel McGregor
P.S.  I'm not offended by anyone being confrontational or not.  I like to think and learn and have fun doing it.  I'm not intending to offend anyone either.  I'm offended by someone ignoring what I say in their response which you certainly have not done.
I'm sorry if I've offended anyone on here.  That is not my intention.
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From: John Kepler [jekepler at amplex.net]
Subject: RE: <VV> Elec fuel pump

And you have largely articulated a semantic distinction without any
significant practical difference!  Your statement is based on some flavor of
absolute relativity.....and is still false (there are MANY substances that
will not vaporize at Standard Temperature and an absolute vacuum!) rather
than relative to STP (like I said, I'm an engineer, not a "blue sky"
scientist and so tend to think in terms of practical reality rather than
academic absolutism).

And, not being confrontational, but just for the sake of discussion.....how
do you figure that the discharge side of a Corvair fuel system is exposed
"...to higher temperatures"?  The feed pipe is actually longer than the
output distribution pipes, larger diameter with corresponding lower fluid
velocity relative to the distribution piping, not to mention that due to the
fan airflow, exposed to (relatively) uniform temps.

John