EFI system design for classic car

[diurno]

Hi guys,

We are currently restoring a MGB GT from 1975, we are in the process of redesigning the fuel system as the car is being fitted with a Mazda MX5 NB engine thus requiring a EFI configuration instead of the carbs.
Our design is going to be as following ~ fuel tank with sender unit --> pre slow continuous flow pump filter --> swirl pot --> pre high flow pump filter --> high flow pump --> t junction with a regulator at one end and the other end gong directly to the fuel rail. Return lines will be coming from the fuel regulator and the swirl pot itself so it drains to the fuel tank once full.

Any recommendations of fuel pumps to use, both to provide the slow continuous flow and the high flow. Or fuel pump shops we need to have a look at?

Thanks!

[Krikkit]

Would a V8 in-tank pump not do?

Also would it not be easier to convert the NB engine to carbs rather than run EFI? That way you can keep it simple, all it needs is a manifold and a couple of carbs of appropriate size.

[stevesingo]

Krikkit said:

Would a V8 in-tank pump not do?

Also would it not be easier to convert the NB engine to carbs rather than run EFI? That way you can keep it simple, all it needs is a manifold and a couple of carbs of appropriate size.

And an ignition system.

[CrutyRammers]

diurno said:

Hi guys,

We are currently restoring a MGB GT from 1975, we are in the process of redesigning the fuel system as the car is being fitted with a Mazda MX5 NB engine thus requiring a EFI configuration instead of the carbs.
Our design is going to be as following ~ fuel tank with sender unit --> pre slow continuous flow pump filter --> swirl pot --> pre high flow pump filter --> high flow pump --> t junction with a regulator at one end and the other end gong directly to the fuel rail. Return lines will be coming from the fuel regulator and the swirl pot itself so it drains to the fuel tank once full.

Any recommendations of fuel pumps to use, both to provide the slow continuous flow and the high flow. Or fuel pump shops we need to have a look at?

Thanks!

Demon tweaks, merlin motorsport etc are good starting points to see what's available for pumps and filters. There only seems to be one or two companies really, from memory lots of the different branded pump are actually made by the same people. Locostbuilders forum probably worth a look as there are lots of people building MX-5 based kit cars on there.

[Snake the Sniper]

Don't forget that the high pressure filter goes AFTER the pump, not before it. The pump has it's own filter and the big one is for the injectors more than anything.