return line to gas tank

[Clarence L.Snyder]

mrvette wrote:
> 
> Yeh, I hear you, but I duno about those immersion pumps, seems that most of them
> are totally out of the fuel when tank is down to say 2 gals or so....and the
> frame rail mounted external pumps of similar design don't seem to need
> that....GENE
> 
Don't need what? The extra flow provided by the fuel return is EXTREMELY
inportant in cooling the pump.
As for the new pumps, they control pressure by contolling delivery
volume, which is controlled by pump speed - pwm controllers. Old systems
controlled pressure by controlling delivery volume - by throwing away
what was not required to provide the required pressure - using diaphragm
type regulators. Different pumps entirely, so cooling is handled
differently as well.
> Dave Balfour wrote:
> >
> > ya it may heat the fuel i wont argue that but i mentioned that it was
> > to cool and lubricate the pump. dave
> > -----Original Message-----
> > From: mrvette <>
> > To: diy_efi at efi332.eng.ohio-state.edu <>
> > Date: Monday, October 19, 1998 5:36 PM
> > Subject: Re: return line to gas tank