return line to gas tank

[Walter Sherwin]

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.................