[Roadsters] Fuel Line size

[RWM (Out of the Office)]

3.5 - 4.0 psi is judged ideal.  Make sure you fit it with an inertial 
kill switch separate from the ignition.

I'll venture the larger diameter fuel line upstream of the pump is to 
lessen suction pumping losses.

- Bob Mann, '68 2000 Solex



steven boortz wrote:
> hi everyone
> i have a related question.  my H20 has 44PHH carbs.  i would like to change to an electric fuel pump.  at what pressure should the pump run?
> thanks in advance
> steve
> 675MIZU
>
>
>
>
> ________________________________
> From: Gary and Cindy Ault <aultgc at att.net>
> To: Paul <9laser3 at bright.net>; Eddie <eddietude at socal.rr.com>
> Cc: Datsun Roadster List <datsun-roadsters at autox.team.net>
> Sent: Monday, February 23, 2009 6:30:21 PM
> Subject: Re: [Roadsters] Fuel Line size
>
> Paul,
>
> Gasoline is essentially incompressible, so the fuel pressure will not 
> contribute to a difference in pressure loss upstream and downstream of the 
> pump.  Differences in fluid velocity will, but I doubt that the use of the 
> same size line upstream and downstream of the pump will make any difference 
> in fuel delivery.  But then, I'm not the engineer who designed the system, 
> so what do I know?  Why the difference in line size?  Beats me.
>
> Gary
> ----- Original Message ----- 
> From: "Paul" <9laser3 at bright.net>
> To: "'Eddie'" <eddietude at socal.rr.com>; "'Gary and Cindy Ault'" 
> <aultgc at att.net>
> Cc: "'Datsun Roadster List'" <datsun-roadsters at autox.team.net>
> Sent: Monday, February 23, 2009 6:20 AM
> Subject: RE: [Roadsters] Fuel Line size
>
>
>   
>> The fuel from the tank to the pump is not under pressure so it requires a
>> larger diameter.  Past the pump, it's pressurized to the carbs.
>>
>> Paul  (Just a guess?)
>> Ohio
>>
>> -----Original Message-----
>> On Behalf Of Eddie
>>
>> IT doesn't make much sense to have varying thicknesses in the fuel line,
>> because the least sized section determines the MOST amount of fuel flow.
>>
>> But, thanks for the info.  Do you have the metal line measurements in
>> fractions?
>>
>> Eddie
>>
>> Gary and Cindy Ault wrote:
>>     
>>> Eddie,
>>>
>>> The fuel line (metal line from the tank) in my '66 measures 0.265
>>> inches OD; the brake lines measure 0.195 inches OD. All lines are
>>> original.
>>>
>>> The rubber fuel line from the filter to the pump is 5/16-inch ID, and
>>> the rubber line from the pump to the carbs is 1/4-inch ID.  Why the
>>> difference, I have no clue.