pugwash

I have to design my fuel system from scratch right up to the ruel rails for the fitment of my LS1 into my off roader.

This is what i have so far:

22gal Jaz foam filled tank
feeding 2 x Facet red tops (working as lift pumps)
feeding 1 2l swirl pot
feeding 1 EFI fuel pump (which must be gravity fed)
feeding 1 regulator (which is t'd for a fuel return (the fuel rails on an LS1 are returnless)
feeding the fuel rails

A few things that i can't decide or don't know.

where do i put the fuel filters? on the low pressure or high pressure side? Does it make any difference and what sort of fuel filter is best for off road- one of the galss globe jobbies that separates out water? the facets have filters in the bottom anyway- are these enough?

where should the return line run to- the tank or the swirl pot? i would guess if it goes to the swirl pot i "could" end up with quite hot fuel as it will just be circulating through the system getting hotter- is this likely?

Does the swirl pot fill from the top, bottom or mid point? i assume i need a return from the swirl pot to the fuel tank- or else what happens when the swirl pot fills up?

how high will the facet pumps lift the fuel- the higher the swirl pot the better for my application, but i don't want the facet pumps to be struggling.

any advice gratefully received

G-Body

iTrader: (4)

I can help with a couple of the questions. You need to run a filter after the high pressure EFI pump. If EFI pump is an external pump you should also run a filter before it (they make special filters for this with less restriction and larger media size), if it is an internal pump the sock/strainer functions as the pre filter.

You don`t want to use the glass filters, use a filter rated for high pressure EFI systems. I just used a filter for a 98 LS1 f-body, it had the quick connect connections and is widely available.

I would run the return line to the main tank, you want to try to avoid allowing air into the secondary tank. I would put the fill for the secondary tank on the bottom and a return line on the top and back to the main tank.

xXxSilveradoxXx

iTrader: (5)

swirl pot = surge tank ???

pugwash

possibly called a surge tank.

in the UK it's a swirl pot and is designed to deliver 2l of fuel under heavy cornering or at extreme angles- stops the EFI pump from burning out due to a lack of fuel!

xXxSilveradoxXx

iTrader: (5)

here is a basic desingn for that surge tank/swirl pot



The EFI fuel pump feed (between the surge tank and the rails) needs to be on the bottom of the tank. The surge tank to main gas tank return line must be on the top of the surge tank. I don't think it matters where the other two lines feed/fill the tank.

I would probably run a fuel cooler after your EFI pump to keep temps low.

As for the filters, I'd agree with G-Body on that.

pugwash

is a fuel cooler necessary or just desirable? unde what sort of conditions can vaporisation occur?

pugwash

hey guys- here are some pics of my fuel rail connection. Why do i have 2 inputs if i have a returnless system (as i should on an 01 Firebird LS1)

bczee

iTrader: (12)

It appears to be a 01-02 F-Body engine (?).. and look like a single input (returnless fuel rail).

There is no EGR on the Intake and if it is a 01-02, it is a LS6 intake.

cherryelky305

iTrader: (2)

That second line is your evap line. It takes fumes from the tank and plumbs it to the front of the intake. If your doing a swap you don't need it but you can hook it up and make it work if you want. Depends on your application

bczee

iTrader: (12)

I removed the EVAP solenoid, I am justing a Charcoal Canister, just pulled a vacumn line line to the EVAP port is on the front side of the intake. The code was removed anyway.

Happy Jim

Do a search on EVAP, take the whole thing off and chuck it in the bin

Jim

pugwash

thanks guys.

Jim- that's the kind of instructions i can deal with!