Holley's Hydramat is now shipping - fuel starve solution?

phunk

The concern with running the Z1 second pump full time is that the driver side of the fuel tank in a Z is generally empty during normal driving, if the fuel gauge is at 1/2 or below.

This is because the factory fuel pump housing has a venturi jet pump that is recovering fuel to the passenger side of the tank so that the fuel pump can pick it up and send it to the engine. The recovery of fuel is quicker than the consumption of fuel, thus if you were to pull over the average Z on the average drive with a 1/2 tank of fuel and open both sides of the tank, you will find that the driver side is empty and the passenger side is full.

The reason the Z suffers starvation is because the fuel sloshes to the driver side of the tank on hard turns, and then there is none for the fuel pump to grab. The venturi jet pump is literally "powered by" bypass fuel leaving the regulator. So when the pump starves, the jet pump dies also. This is why a real bad case of starvation can leave you on the side of the road even with a significant amount of fuel in the tank. If you slosh it bad enough, there is just none for the pump, and the jet pump is dead due to no fuel leaving the regulator.

The Z1 kit eliminates starvation by "supercharging" the recovery of fuel to the passenger side by pumping it there with an actual fuel pump. This will make the driver side of the tank far more prone to just being entirely empty when driving the car at 1/2 tank or below, especially on the street where you will rarely turn hard enough to slosh fuel back over to it.

Electronic fuel pumps dont have a great lifespan when they run dry because the gasoline is what cools and lubricates them.

So if you DO use your Z1 kit on the street, I would highly recommend you put a toggle switch on it so you can turn it off. On the track it should be fine as it will constantly get sloshed fuel. On the street, it will run dry for long period.

The CJM RRP is a surge can system that operates under an entirely different principle and it is normal and required that both pumps run all the time.

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