Re: [DML] Fuel Cell Question.

["DMC Joe" <dmcjoe@xxxx>]

Walt said:
"The biggest reason for the pump being mounted in the tank is that all
electric fuel pumps in general are better at pushing fuel than sucking it.
In fact, they suck so badly [sic] that they try to get them as close to the
bottom of the tank as possible."

Walt is correct. In several other versions (Volvo, etc.) of the Bosch
K-Jetronic fuel system where the pump is mounted outside of the tank an
additional fuel pump (primer pump) is mounted inside the tank to assist fuel
delivery to the main fuel pump.

DMC Joe
DeLorean Help dmchelp@xxxx
www.dmc.tv
http://shopping.oraclesmallbusiness.com/dsvstore
----- Original Message -----
From: "Walter Coe" <Whalt@xxxx>
To: <dmcnews@xxxxxxxxxxxxxxx>
Sent: Monday, February 04, 2002 1:14 AM
Subject: Re: [DML] Fuel Cell Question.


> > Was the mounting of the fuel pump inside of the fuel tank to save
> > space, or was it a safety concern? In other words, if the pump
> > was mounted outside of the tank, is there a possibility that it
> > could be punctured, and the electrical connections exposed?
>
> The biggest reason for the pump being mounted in the tank is that all
> electric fuel pumps in general are better at pushing fuel than sucking it.
> In fact, they suck so badly [sic] that they try to get them as close to
the
> bottom of the tank as possible.
>
> There is another list member, Andrei Cular, who mounted his fuel pump
> outside of the tank. I think his goal was to save on buying a new fuel
pump
> boot, so he made his own that was basically a cap. I haven't heard him
give
> any complaints with this arrangement. So perhaps these fuel pumps suck
well
> [sic] after all.
>
> I doubt that locating the fuel pump in the tank has anything to do with
> safety or saving space. My biggest concern with what Andrei did is that I
> question whether or not a Bosch fuel pump can reliably suck that good [sic
> again!]. I have looked through a lot of high performance automotive
> catalogues and have yet to see anything that can begin to replace the pump
> used in the DeLorean who's Bosch continuous injection requires fuel
> pressures in the range of 72-81 psi. As fuel systems go, that is
extremely
> high. As a comparison, the Bosch intermittent injection requires 31-40
psi,
> domestic throttle-body injection uses 10-11 psi, and typical carburetor
> systems use 1-2 psi.
>
> For what it's worth, my humble opinion is to just use the OEM setup with
all
> it's quirks. But if you can come up with something that makes less noise
> and doesn't require an exotic fuel suction hose, then I would like to see
> that.
>
> Walt Tampa, FL
>