chris-m

need a little basic advice please as fairly new to carb installs. I'll be feeding a 650cfm carb and have been advised to use a Federal Mogul Electric Fuel Pump (72GPH) by my UK supplier, which is internally regulated to 6.5psi apparently. Assuming that i do not therefore need an external fuel pressure regulator, do i just feed the fuel line direct to the carb, or does it still need a fuel return back to the tank from somewhere for when the car is idling etc?

ie can you just feed fuel at 6.5psi direct to the carb from this pump without probs? or have i misunderstood and the pump has its own return line to the tank?

fuel pump
http://www.roadcraftuk.co.uk/index.a...egory=Electric

cheers

chris-m

anyone advise please? supplier advises that the pump in question doesnt need a regulator.

or shall i stick to a more regular pump with external pressure regulator and a fuel return port from that back to tank?

bczee

iTrader: (12)

If the pump is regulated to 6.5 psi.. basically you should be able to connect it directly to the Carb.. but I don't know this pump.

Does that pump have a return port ? I can not see from the picture. If it does, I would pipe it back to the tank. If not and it was me... I would feel better wtih a regulator and return line.

chris-m

yeah i was wondering that. if it doesnt have a return port then you have no option but to feed direct to carb, hence worries about carb flooding etc?

if it has a return i'd find it easier to understand as far as that goes, no worries then about carb flooding.

Andy1

I am not familiar with this particular fuel pump either, but it is not uncommon to run a regulated output fuel pump directly to the carburetor. Been done that way for many years. No bypass or return line is necessary. Carburetor flooding will not be an issue unless that particular carburetor requires a lower fuel pressure than 6.5psi. Now I did notice you said "apparently." Perhaps you should do a search on the NET to make sure the pump output (specifications) is what your supplier claims. Do you have the model number of the pump?

Andy1

bygblok

iTrader: (4)

internally regulated at 6.5? I'd almost have to see the GPH rating of the pump to make sure it will feed a high output motor like an LS. If you have anything done to it you'll need even more. I'd go ahead with a walbro 255(in tank) or a good aeromotive pump and run a regulator with a return line up by the motor. This way if you NEED more pump flow you have the option and don't limit yourself before you ever fire it off. Just my opinion......

Andy1

Do you really think he needs that much pump? It's only a 650CFM carb. An old style SBC stock type diaphram pump could feed that carb with plenty to spare........At least that's how I remember it The poster mentions the FM electric pump puts out 72GPH. 72GPH = 272 Liters/hr

Andy1

stevieturbo

Thats a pretty big pump !!!! at least in terms of flow.

I used one ages ago as a lift pump for a swirl tank, although I think mine was a 100GPH version from Real Steel.
There is no return port. Just inlet ant outlet.

For sake of cost, I would fit a fuel pressure regulator. I wouldnt want to rely on the pump controlling the pressure against the needle valve of the carb itself.
you could even use one of "Filter King" reg's, with built in filter. Demon Tweeks etc list a lot of crap like that in their red catalogue.

If it was possible, I would go for a full return style system with matching reg, although it will be more work to plumb up.
Probably isnt necessary though.

Oh, and I've just twigged on who you are

And from what I recall...those little pumps are noisy chug chug chug..not a nice sound. Although when engines running you wont hear it prob.

I had mine mounted in the boot of my first black car, drawing from the tank, then feeding to a swirl tank, which then fed an Aeromotive pump.

stevieturbo

In carb/low pressure form, most efi pumps will flow more than enough fuel for your goals.

Bosch pumps can be found on ebay pretty cheap, as can the in-tank Walbros if thats what you want.

These would def require a return style regulator.

ALthough pre pump filtration requirements of an efi pump, will be stricter than a conventional low pressure pump. EFI fuel supply needs to be clean, as the internals of the pump are small, and dont like dirt.
EFI pumps also dont draw fuel very well, they must be mounted lower than the fuel level.

Low pressure pumps, tend to suck better, so are more flexible in their mounting location.

Years ago before my black car was fuel injected, I ran the twin turbo with a blow through Holley. Fuel tank was from a Saab turbo, along with its Bosch efi pump, in-line style, albeit mounted in tank. Id guess it had around 400bhp, and I never had any fuel supply issues. I used a return style reg, same as fitted to a lot of carb#d turbo cars ( metro, maestro, Esprit, R5T etc etc )
I know for a fact, the Leyland turbo carb cars all used the same Malpassi regulator.

stevieturbo

http://www.federal-mogul.com/en/Afte...ps/RotaryVane/

Given that FM/Carter say it can generate up to 18psi.... I would defo be fitting a regulator.

chris-m

Hi Stevie ;-)

I was given that pump ref as a preference by the UK importer of the edelbrock /msd manifold kit thats all, he mentioned it being ideal for the job, not so sure now from comments! think i'll stick with a simple pump/regulator and return setup to be safe.
cost is negligeable anyway to stick in a regulator, it just seemed to make sense if a pump was available with inbuilt regulator to run it in one unit.
rgds