return line to gas tank

[mrvette]

only problem I had with  'hot aerated' fuel into the engine was that the fuel
pump made noise, a sure sign of cavitation,  not good for it's design i was
sure......but at 30-40 pounds pressure,  the fuel is not aerated by the time it
gets to the engine....at least not significantly  so it was a pump longevity
problem, and I tend to want to err on the conservative side....GENE

Walter Sherwin wrote:
> 
> I think there was some confusion.  All I was trying to say was to discharge
> the return fuel below the liquid level line most commonly in the tank, and
> make sure that the discharge was not pointed right at the pickup.  Of course
> the fuel tank must be able to either vent to the atmosphere, or to a
> charcoal evaporative cannister.  Otherwise a pressure build-up will occur.
> You are right, GM does not do this in a lot of cases, but often this has
> been to accommodate efficient manufacturing and assembly (IMHO).  Think
> about it, why would you want to immediately recycle hot, aerated fuel back
> to the engine?  By the way what is the reverse system you describe?  Sounds
> funny.
> 
> -----Original Message-----
> From: mrvette <mrvette at bellsouth.net>
> To: diy_efi at efi332.eng.ohio-state.edu <diy_efi at efi332.eng.ohio-state.edu>
> Date: Monday, October 19, 1998 6:58 PM
> Subject: Re: return line to gas tank
> 
> >In fact the General does not do it that way,   there is a reservoir as you
> say,
> >but the return line is aimed rite at the pickup....I tried to recirculate
> the
> >fuel by a reverse system, feeding into the suction line, and it did not
> >work...engine ran ok, but pump was in obvious distress, listening to it
> run,  so
> >I put the return into the tank, as per normal, and have tolerated the
> problems
> >previously mentioned...GENE
> >
> >Walter Sherwin wrote:
> >>
> >> I think you may want to address two different aspects, when designing
> your
> >> TBI recirculating fuel system.  You want to create a replenishing
> reservoir
> >> (dam) around your in-tank fuel pump pickup point in order to prevent
> >> starvation during braking and cornering.  However, you should always keep
> >> the return line discharge as far away from the pump pickup point as
> >> possible.  In fact,  you should make sure that the return line extends to
> >> the floor area of the tank and discharges away from the pump pickup.  If
> you
> >> don't,  then you will have a lot of trouble with foaming, hot fuel, and
> >> vapor related issues.  When possible, it is always best to use an in-tank
> >> fuel pump with strainer sock.   OEM's often try to isolate the hot return
> >> fuel, from the rest of the bulk fuel, in order to improve evaporative
> >> emissions.  However, I would think that you would be more interested in
> >> cool, bubble free fuel.  Bye.................

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