[V8] returnless systems and vapor lock

[dsaad at icehouse.net]

This is how I see it too Tony - but how is returnless cheaper?
You still need regulated pressure, and the FPR we all know and love is modulated
by manifold vacuum as it should be, so how does the returnless work?

And Steve - you hit it - the fuel picks up a lot of heat in the fuel rails.
Back in the bad old carburator(sp?) days, they went to a return line to prevent
vapor lock (I think anyway). With higher fuel pressures, that is probably less a
problem than it used to be, but still a problem

Dave


>
> Tony Hoffman <unsnip>
> Actually, in my understanding, it's quite the opposite.  Fuel cooling
> through
> recirculating to the tank is considered a plus (the tank is the cooler) and
> the return system provides a means to purge air that might be in the system.
> A
> return system also promotes better hot re-starts 'cause the hot-soaked fuel
> is immediately replaced with fresh, cool fuel. Yet another advantage of a
> return system is the ability to modulate fuel pressure through control of the
> FPR.
> The reason mfrs went to a returnless system was cost-reduction, pure and
> simple.
>
> YMMV
> Craig Nicol
> _______________________________________________
> Audifans V8 mailing list
> Send posts to: mailto:V8 at audifans.com
> Manage your list connection: http://www.audifans.com/mailman/listinfo/v8
> Have an Audi V8 question?  Check the Audifans Knowledgebase!
> http://www.audifans.com/twiki/bin/view/Audi/V8
> Have a V8 answer? ... Please help others by adding to the KB ... all
> contributions welcome!
>