Mazda used to have a vibrator pump sitting on top of the left rear wheel house. It was a coil wound around a sleeve with a piston inside. The piston had a hole through the center and one way ball valves at both ends.

An SCR and perhaps a few other components would charge the coil pulling the piston to center up in the coil.

 

When the field was fully charged the SCR opened and a spring pushed the piston toward the fuel supply. And the cycle would repeat. The pump was mounted on rubber standoffs with a flex ground strap. These things were square laminated frames with a single wire lead. Very small. Maybe made 2 pounds of pressure.

 

The car would loose power based on how old the pump was. Mazda used a bypass to return fuel to the tank, and the carb (Niki 4BBL) used only about a pound of fuel pressure. So top speed died off with pump wear. That same pump worked fine when moved to below the fuel level, beside the tank, to keep it charged. It had good suction lift, but very low displacement/volume.

 

For 250 HP I use two Carter 7 PSI street rod pumps. I regulate with a Holly regulator to 6 PSI at the carb inlet.

One 7 PSI Carter could not hold 6 PSI to the end of a long straight. The Devils own fuel consumption at .666.

 

In unmodified form the Weber will not shut off more than about 3 1/2 PSI. Then if you run over some bumps and get fuel sloshing about in the bowl, you might get rich splash and poor running even at that.

 

Two Carter pumps is enough to run three race cars. However, it is the nature of race cars to unport the fuel pickups about half of the time. So you want a large displacement pump to re-acquire the fuel supply with great suction lift at high volume. This will also result in air being pushed to the carb in large quantities, and you want air pushed through and out quickly, so there is no loss in power caused by low fuel levels in the bowl (lean).

 

The pumps (most pump) are run full of fuel even the motor. They are fuel cooled and lubricated, so they last longer in a premix situation.

 

They are internally regulated to (depends on the model) to 7 PSI. You must regulate the output to less than that.

 

Carters use sliding vanes. The Holly's had little rollers and seized with the smallest piece of debris.

 

You can process much bigger stuff with a Carter. Use a filter in front of and after any pumps.

 

The advantage of the over sized pump is suction lift and large displacement. Much shorter quiet times in the event you run a tank dry or unport the supply in a slip. Or steep descent or Viking departure. Cheap enough to replace every year or two. 

 

Always installed lower than the lowest fuel level. Fuel under pressure has a higher boiling temp than fuel in a suction line.  

 

The Holly regulator has two outlet ports, so one can be used for the fuel pressure sender. They work great and are cheap. Sold under many brand names.

 

A gag used in race cars to keep from unporting the supply is to have a tall skinny cylinder in the tank or fuel cell. All return fuel from injectors rails or a transferr pump is dropped into this cylinder. All fuel for the engine is removed from the bottom of this cylinder. The top of the cylinder is open, so when over full the fuel is just dropped back onto the tank floor. 

 

You can run the fuel supply to very nearly zero with this system.

 

Similar to a make up tank but inside the fuel cell there is no worry of fuel leaks or exposed lines running everywhere. 

 

You can order the cylinder or bottle from Aeroquip in their cells. Aluminum or fiberglass works fine as well.

 

I can make a drawing if anyone needs it.

 

Lynn E. Hanover