may be a stupid Q about fueling

shuffbag · Post by **shuffbag** » Mon Jun 16, 2008 9:07 pm

im trying to wrap my head around surge tanks and why they are required?

i understand needing to add a return line but why could i not just use the factory fuel pump that came from the same car (ej22 lib) as the engine? as its has no forced induction nor is it going to be a performance beast.

this is my first engine swap and im trying to wrap my head around all this.

YouTube · Post by **El_Freddo** » Mon Jun 16, 2008 9:36 pm

Hey shuffbag,

I'm presuming that your fitting the EJ into an L series or MY? If thats the case, your fuel tank will not be designed to stop the fuel from sloshing around too much.

The idea of the surge tank is to create a small tank that is fed by the standard fuel pump as well as the returning fuel from the engine that is unused. From here the hi-pressure or EFI fuel pump takes its fuel from here without being allowed to starve of fuel. An EFI pump that starves of fuel for a few seconds too many times will toast itself.

This little tank, while not loved by everyone due to heating the fuel and a few other issues, are an easy fix to the non-efi fuel tank problem.

Cheers

Bennie

shuffbag · Post by **shuffbag** » Mon Jun 16, 2008 9:46 pm

so fuel pump with no fuel = no pump at all

so its all about constant fuel delivery even when the tank gets low. could the higher pressure fuel pump wiring just be spliced in with the standard L series pumps wiring? and could the factory ej pump be used as the high pressure pump, just asking because i still have the almost stripped lib in my backyard.

anyone want some cheap gen1 lib stuff?

YouTube · Post by **El_Freddo** » Mon Jun 16, 2008 9:51 pm

Shuffbag, It wouldn't be hard to run the standard EJ fuel pump off the power to the standard low pressure pump through a relay. You could also have a kill switch for the high pressure pump as a safety measure and to help prime the surge tank.

And yes, the high pressure pump needs constant fuel delivery with as little air as possible. There maybe some cavitation (air in the system) but so long as there is adequate fuel for cooling and lubricating of the high pressure pump all will be good...

The overflow from the surge tank goes back to the main fuel tank, otherwise you'd end up with a very pressurised system...

Cheers

Bennie

brumbyrunner · Post by **brumbyrunner** » Mon Jun 16, 2008 9:53 pm

Your doner Lib has an in-tank pump while the easiest way to plumb a surge tank is with an external pump. They are cheap and you'll know it's brand new.

YouTube · Post by **El_Freddo** » Mon Jun 16, 2008 10:24 pm

brumbyrunner wrote:Your doner Lib has an in-tank pump while the easiest way to plumb a surge tank is with an external pump. They are cheap and you'll know it's brand new.

My bad, I thought the Lib runs an external pump. In which case, pumps to price for the best bang for your buck are:

-VL commodore turbo
-5 litre VN commodore

These are the only two I know of. When in perth the VN option was $200, at my parts joint in romsey I know its about $150. The subi replacement option from perth was quoted at $390+!!!

Crazy.

Good luck with it.

Cheers

Bennie