Electric fuel pump - dry prime height

[S2r]

Quick question, what does 'dry prime height' mean?

I'm replacing an electric fuel pump on a buggy and having looked, some such as facet say that they have a dry prime height of 300mm... what does that refer to?

[stevieturbo]

I presume it means it can prime if the pump is mounted 300mm higher than the fuel itself.

It's always best practise to gravity feed pumps, and always gravity feed EFI type pumps

[anonymous-user]

Broadly it is the height of fuel, vertically, up which the pump can pull when it is dry, ie there is no fuel currently in the pump.

So, a dry pump, mounted 300 mm above the surface of a tank of fuel must have at least a 300mm "dry prime height" in order to pull the fuel up into itself and prime. Once primed, the pump has a much easier time of pulling fuel into itself because the liquid fuel helps seal all the small gaps around the pumping elements. This is why the "dry prime" height will be less than the "wet prime height"

However, i'd recommend trying to get the pump as closer too, or even below the tank if you can, and make sure it's fed with a bigger pipe than leaves the pump on the pressure side, in order to minimise suction losses and maximise the pumps efficiency

[S2r]

Thanks for the replies, that's great... the pump will be below the tank so it sounds like it should be fine.