A question for all you EFi guru's

I am trying to work out my fuel delivery and have decided I need a low pressure fuel pump to a swirl pot and then i want to use the original sierra EFi pump.

My question is this - do I need to match the delivery rate of the LP pump to the delivery rate of the HP pump ? (I am worried that the swirl pot will be emptied faster than the LP pump can refill it!) and if so how do I find out the rate for a standard sierra 2.0 Pinto EFi pump ?

Cheers

quote:

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Originally posted by DaveFJ
A question for all you EFi guru's

I am trying to work out my fuel delivery and have decided I need a low pressure fuel pump to a swirl pot and then i want to use the original sierra EFi pump.

My question is this - do I need to match the delivery rate of the LP pump to the delivery rate of the HP pump ? (I am worried that the swirl pot will be emptied faster than the LP pump can refill it!) and if so how do I find out the rate for a standard sierra 2.0 Pinto EFi pump ?

Cheers

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Yep, as long as HP pump returns back to swirl pot, the LP pump only needs to replace what the engine uses, though in practice you would want a fair bit more flow than that.

any reccomendations for an LP pump then ? been looking at the facet pumps and can get them fairly cheaply on ebay so just need to know what type... do I need one of the little square jobbies or do i need one of the cylindrical ones? red/silver top ?

any advice gratefully recieved!

cheers

It would also help if the fuel return to the swirl pot went through a cooler, such as a small oil cooler.

Most cars rely on the airflow under the car and the surface of the tank to keep fuel temp down.

Cheers,
Syd.

nice tip... I am currently working out exactly how to install my pumps/filters etc so can look to include some form of cooler as well.

I am going to try to mount most of the components on a plate for convenience of fitting and future maintenance. I am going to use the standard sierra HP pump for now with a view to upgrading it later if/when I finally change from a Pinto to a cosworth lump...

so here is a very quick sketch of my plan so far - have I missed anything ? fuel px reg will be at engine post hp filter - is this correct?



Description

[Edited on 7/6/06 by DaveFJ]

The pressure regulator is fitted into the return side, usualy mounted on the end of the fuel rail in OEM systems.

mhhh

i wouldnīt cool the fuel..

i would just mount 2 efi pumps!!

one from a 3,5 liter engine the other from a 2,0 engine..

should be enough difference to have the swirlpot filled up...

also i donīt like the idea that one pump pumps in while the other does that to!!

sow in fact energie gets loss...

if you want cold petrol i would mount that fuel cooler in front of the radiator

also while stationairy it will heat up..

Tks

the problem is that the EFI pump must be gravity fed. My tank has connections on top therefore I need a pump that can draw the fuel up and into the swirl pot....

If you can find an automatic Metro, they've got a nice little oil cooler, with JIC fittings. Give it a good flush and it should work fine. As long as it gets a little airflow, it should be OK. The idea is not to 'chill' the fuel, just get rid of accumulated heat.

The cooling is necessary because the fuel is heated by ...the pump... radiated heat in the engine bay, ...and the injectors.

Too much heat and vapour locks can happen, and usually at the worst time possible.

At least that's the story in the cars I've been working with. When they have to run flat for 24 hours, you want everything right.

Cheers,
Syd.

my efi pump is standard sierra and isnīt gravity fed!!

would be very bad haveing connections downwards..

if they leak!!

i use a complete sender,return,pickup,filter unit from a old beamer (635i)

i folded the perfil plane and screwed it with tapers in a bath of front screen black silicone...

Tks

In general HP pumps are not too good at sucking & like a head of fuel above them. The hot ticket is definitely a facet LP pump feeding a swirlpot as in the above diagram. The LP pump can be specified to match the engines fuel requirement which shouldn't be too great for a 2 lt.
Cheers
Ian