return line to gas tank

[Shannen Durphey]

Here's a thought.
The regulator can be mounted on the tank, especially if it is a simple
spring type like the TBI units.  The regulator is mounted to a tee
which vents the majority of the fuel back to the tank without ever
reaching the engine.  But this leaves a dead end at the far side of
the fual rail, and no way to purge vapor.  (Vapor will form, in hot
climates, high loads, and especially engine off hot soak.)  So, a
small bleed line returns some fuel from the rail to the tank.  Sure it
will absorb some heat, but it will be far less than the traditional
system we're familiar with.  The part that needs figuring out (Gee
Whiz engineering for me) is correct bleed tube size for sufficient
fuel at WOT.  Since I'm not familiar with fuel pump #'s I can't say
whether or not a stock capacity pump could handle this.  At this point
I'd bet so.

BTW, the returnless EFI systems typically run higher pressures.  My
opinion is that the pressure increase is an attempt to overcome vapor
problems.
Shannen 

Stowe, Ted-SEA wrote:
> 
> that's interesting, are those TBI or real EFI ?
> what is the fuel pump pressure ? on second thought, it might be hard to
> mount this dude in my mgb tank. return to plan A.
> 
> -----Original Message-----
> From: David A. Cooley [mailto:n5xmt at bellsouth.net]
> Sent: Monday, October 19, 1998 6:07 PM
> To: diy_efi at efi332.eng.ohio-state.edu
> Subject: Re: return line to gas tank
> 
> If you look at the late model Chryslers, specifically the neons, they use
> an in-tank pump for the EFI with the fuel pressure reg. built into the pump
> assy.  No return line at all
> 
> At 07:46 PM 10/19/98 -0400, you wrote:
> >No the canister systems are either built into the tank or of an
> arrangement they
> >won't fit an earlier tank...so I just live with the suden loss/power when
> under
> >hard acceleration....it's a reminder to fill up....;-(((.....Oh I know how
> the
> >Bosch vac reg fuel pressure thingy works....but I hear there is a SS
> driven pump
> >of quick enuff recovery to get away from that system, so just one fuel
> line is
> >required....
> >
> 
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>            David Cooley N5XMT           Internet: N5XMT at bellsouth.net
>      Packet: N5XMT at KQ4LO.#INT.NC.USA.NA   T.A.P.R. Member #7068
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