Corvette Fuel Systems - Fueling The Fire

Planning & Setting Up A Fuel System For Your Corvette

Wayne Scraba Jul 20, 2009 0 Comment(s)
Corp_0908_02_z Corvette_fuel_systems 2/11

This is the MagnaFuel pump we're using in a home-brewed 572. This pump can support an EFI or carbureted engine that produces 1,500 HP. For the modified normally aspirated application (and most others), this pretty much exceeds the engine requirements. This pump can deliver anywhere from 20-120 PSI in use. When it was designed, MagnaFuel took other considerations into account. One of the most important was a steady fuel delivery curve from idle to full throttle. Another was quick response coupled with maximum cooling. Because of these design factors, reliability isn't a problem. The body of the pump is machined from 6061-T6 aircraft grade aluminum alloy. Internally, the pump uses a proprietary gear drive, flow-through configuration, allowing for big pressure capability, reliability and quiet operation in one package.

The pump is also quiet. Now, that's not a big deal for a Corvette with a large displacement, barely muffled engine on board, it's probably not a big consideration, but if you have something a wee bit tamer, there's a good chance the drone factor could drive you nuts. Internally, this particular pump incorporates double support bearings and uses polymer wear plates (which obviously contribute to the low noise and smooth operation). The actual layout and construction of the pump eliminates the need for shaft seals. Without shaft seals, then there's nothing to leak (aside from an O-ring, which as most know are regularly reliable).

One thing we mandated for our application (a home-brewed 572 cubic inch combination) was a pump that didn't require an electrical step down device to reduce current draw. This particular fuel pump is based around a high-torque custom motor with very low current draw (12 amps at 45 PSI). This also means you don't have to wire in a relay for the pump (although you can). The other piece of the puzzle as far as we were concerned was the capability to rebuild it if necessary. The MagnaFuel pump is completely rebuildable with a simple O-ring and wear plate kit.

Sharp readers will note this piece is actually an electronic fuel injection pump. How can you use it with a carburetor? Simple. Remember that by-pass arrangement mentioned above? MagnaFuel offers a by-pass package for these pumps and it is much like the system used in the big Pro Stock fuel delivery systems. It simply threads on the outlet of the pump. In operation, you set the final outlet pressure (from the pump to the regulator) you desire by swapping out by-pass springs. The balance of the fuel (excess) is by-passed and sent back to the tank. That process eliminates the "dead-heading" dilemma we alluded to earlier.

So how do you regulate the fuel? Even though unnecessary fuel is bypassed back to the tank, some form of device to control fuel pressure is essential (that's no secret). Typically, two different types of fuel control devices are available. One group is engineered for carburetors while the other is designed for fuel injected engines. Electronically fuel injected engines mandate operating pressures ranging from 35-85 PSI. Meanwhile, carbureted engines typically see operating pressures in the 4-12 PSI range. You can get two or four port (outlet) regulators, and you can usually obtain them with or without boost reference capability (meaning the regulator is designed to work in conjunction with a blower of some sort). In both families (EFI or carburetor), you'll find regulators grouped into the horsepower level (engine) they are designed to sustain. For a serious performance application, an adjustable regulator is an absolute necessity.

Remember when we mentioned the capability of field-servicing an electric fuel pump? The same applies to the regulator. You should look for something like the MagnaFuel regulator design where a removable cartridge is employed. Here, the basic internals of the regulator can be inspected or replaced without removing the regulator body from the respective mounts or without removing the hoses.


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