The days of electronic fuel injection referred to as Black Magic are over. It has taken hot rodders long enough to figure out carburetion, and with the advent of EFI, the fear of "something new" struck deep. That isn't the case any longer.
The movement in the world of street rods toward technology is accelerating faster and faster. Rodding has long been the bearer of "things old," but technology is currently embraced in both its "natural" and "altered" states. Techno rodders are split into two groups: those who embrace technology and its appearance and those who embrace it but want the vintage look. The rush toward technology started slow enough; first there was electronic cruise control, power windows and antennas, digital gauges, electronic ignitions, and then came the computer. It wasn't long before electronics "slipped" into our world of engines, transmissions, and all matters mechanical.
And that brings us to the first of a multi-part series on the whys and wherefores of converting from carburetion to modern electronic fuel injection. To gather the background info, we worked with COMP Cams (fuel injection camshafts), FAST (Fuel Air Spark Technology on computers for engine management), Tanks Inc. (fuel injection gas tanks), Street & Performance (complete EFI engines and accessories), Pure Choice (plumbing), and Lokar (cables).
When entertaining the idea of converting from carburetion to fuel injection, an old axiom comes to mind: "Plan your work, work your plan." Aside from removing the carburetor(s), we will give consideration as to what type of fuel injection, throttle body (atop a carb intake), or a plenum chamber/throttle body style we will want to run. Each has its advantage, whether it's initial cost, ease of installation, and/or which will work best with the engine management system you select. Next up is the gas tank, which now requires a return line; the fuel pump-no longer will your mechanical pump be sufficient-and then there's the matter of an external pump (typically mounted to the frame) or an internal pump (such as an OEM submersible); plumbing, remember you will need a feed line (which you have), but you will require a return line to bring back unused fuel to the tank; revamped throttle cable and at least the upper radiator hose (and possibly rework the water inlet), this isn't difficult as there are components on the market to achieve this goal.
There are a number of minor to major adjustments such as the possibility of finding a new location for your alternator, new air cleaner positioning, and finding a home for the engine control unit (CPU, computer) and the wiring loom (more wires for a complement of sensors).
Fuel Delivery System
Let's begin this project at the back and work our way to the front. The gas tank and the fuel pump are important decisions to be made before you purchase any of the fuel injection components. The gas tank will require a feed and a return line. Always use fuel line that is rated for fuel injection use as the pressure with this system is greater than that of a carburetor-equipped engine. Hard line, rated rubber, or stainless steel braided line will work with a 3/8-inch supply side hose and a 5/16-inch return hose.
You will have to make a decision on external or internal (submersible gas tank) fuel pumps. There are things to take into consideration with both, but we will get more into that in part two. However, two experts in the field, Mark Campbell of S&P and John Pazik of Tanks Inc., prefer the in-tank fuel pump for several noteworthy points: smooth and quiet operation, fuel pump is cooled (helps to eliminate vapor lock) by the very gas it resides within, and much longer pump life expectancy.
You will need to replace your fuel lines within the engine compartment as well as come up with fittings that get the job done and look good as well. We dropped by Pure Choice at the Nats and picked up some fittings, fuel filter, and bracket as well as some good info.
Injector Size
This is a tough one for street rodders since we all think our engines produce gobs more horsepower than they really do. Just as in carburetors, oftentimes smaller is better.