Fuel pump questions

[Shannen Durphey]

Frederic Breitwieser wrote:

> >Then, someone says the fuel shouldn't drop into the tank .... have
> >I done something potentially dangerous ?    been running like this
> >for almost two years !!   could it be that it creates more in-tank
> >vapors ??  (doesn't sound right to me ??) .... or that it allows the
>
> The trickling down the filler neck can in some cases cause the fuel to be a
> little aerated, however I don't think it would be anywhere near enough to
> be noticable, consider the flow back (trickle) versus the flow to the fuel
> rail (much more).
>
> It would be fun to try and figure out some math, but as you said, works for
> 2 years without a hitch, that's scientific enough for me.  Most in-tank
> fuel pump systems have a return line, that drops off the top of the tank
> fitting about 1", so if your tank has less than 1" of fuel, its falling
> through air to reach the fuel level, wherever that is.  So, I don't think
> running down the neck is a real problem at all.
>
> Frederic Breitwieser
> Homebrew Automotive Mailing List
> Bridgeport, CT 06606
> http://www.geocities.com/MotorCity/Downs/4605/index.html
> (Portable Webserver Link Address)
>
> 1989 AG Hummer 4-Door
> 1993 Supercharged Lincoln Continental
> 2000 Mid-Engine Sports Car <smile>
>
> ---

  GM runs the return line parallel to the feed line and ends one where the
other begins. They don't seem to like to allow the fuel to stir up too much,
either.

Shannen