One key to a successful electronic fuel injection conversion is, and always will be, to employ a high-quality fuel delivery system. If constant, pressurized fuel can’t make it to the injectors the best EFI system in the world will perform poorly. This may sound simple enough, but the devil is—as they say—in the details, and the fine points will make or break a good installation.
It is in Holley’s best interest as a fuel injection manufacturer to come up with a quality system that will work under grueling street conditions and high-g loads. They offer a few different universal fuel tank conversion kits and the HydraMat filter/pickup works very well. But the best situation is to create a fuel tank with a built-in fuel reservoir and then make those tanks for the popular performance cars like Camaros, Chevelles, Corvettes, Novas, and even trucks.
That’s exactly what the Sniper fuel delivery system is all about. The kit comes with a Holley performance “pump-on-a-stick” system with a specific flange to mount the pump assembly inside a large reservoir located at the front of the tank. Alongside the pump assembly is a fuel level float assembly to drive the gas gauge.
Our plan was to upgrade our LS-powered Chevelle from a carburetor over to EFI using Holley’s HP EFI ECU to transform this Chevelle over to 21st century fuel control. When Holley released the Sniper line with a dedicated fuel tank for this conversion, it became a moral imperative to make the conversion. Our old system used an externally mounted fuel pump and stock tank pickup with a return back to the tank. It worked fine for our carbureted application, but it would have been inadequate for the constant EFI fuel pressure requirements.
Our new engine is an iron 6.0L LS with TFS heads that recently came off the dyno making 556 hp. The standard Sniper system uses a 255-lph (liter per hour) pump that is rated to deliver up to 550 hp worth of fuel at EFI pressures. Since one of the possible upgrades would be an NOS nitrous system controlled by the Holley HP, that entry-level pump capacity was going to be insufficient. Luckily, Holley offers an optional 400-lph pump intended just for gasoline that bumps the rated capacity to 750 naturally aspirated hp, which fits perfectly into our upgrade plans.
Perhaps the most important advantage to an in-tank pump is that the inlet to the pump is always submerged in fuel and does not have to “pull” fuel from the tank to the inlet as with an externally mounted pump. A standing column of fuel above an in-tank pump uses the weight of this fuel to push fuel into the inlet, improving pump efficiency. Plus, since the pump is submerged in fuel the pump will run much cooler, which improves durability.
Our current fuel delivery system was more than 10 years old and used older, rubber-lined braided steel hose. Because this car often sits for months at a time between test sessions, rubber fuel hose can quickly become brittle after alternating between wet and dry sessions. This drying cycle takes a toll on any rubber-lined fuel hose. We added a length of hard line, which helps, but the real solution was to replace the flexible hose lengths with a more durable material.
For years, the OEs have been using what is often referred to as plastic fuel line. The material is actually carbon-infused PTFE. This acronym stands for Poly-Tetra-Fluoro-Ethylene, which has also been known by the brand name Teflon. This material is extremely resistant to all types of fuel—even methanol and nitromethane—and if not abraded or exposed to open flame, offers an extremely long lifespan. Because of its strength and wall thickness, the material is somewhat stiff, necessitating a wide bend radius to prevent kinks.
Holley’s UltraPro hose uses a convoluted, or corrugated, wall construction that makes this hose both light and very easy to route with a very tight bend radius. When fuel is pushed through standard, white PTFE hose, the material is not a conductor so static electricity can build up on the line and cause pinhole leaks. UltraPro hose is carbon-infused (black), making it a safe conductor so there’s no chance of a buildup of static electricity.
Make no mistake, the UltraPro hose and its specific fittings are expensive, but we’re talking about a high-pressure fuel delivery system, which demands we make it as safe as possible. Investing in the Earl’s hose and fittings is likely to make this the last fuel delivery system this car will need. Plus, it is completely compatible with different fuels, such as E85, should we decide to experiment with that fuel in this car.
With this relatively simple installation, we now have a very nice in-tank fuel delivery system capable of feeding 750 hp that looks nearly stock when mounted in the car, and will work flawlessly with our new EFI system. It’s much cleaner than our previous effort, and that production-style fuel pump will last for years. Other than more horsepower, what more could you ask for? CHP
|EFI Tank and Fuel System Applications|
|We’ve combined different year spans of cars to abbreviate this list as there are specific tanks for each body style application. But if you’re driving a popular Chevy body style, it’s likely Holley offers a tank for it.|
|1978-’88 Malibu/Monte Carlo|
|Sniper Fuel Delivery system, w/ 400-lph pump||SNE-19-405||Summit Racing|
|Sniper Fuel Delivery system, w/ 255-lph pump||SNE-19-105||Summit Racing|
|Earl’s -6 AN male to -8 AN male reducer (2)||AT991912ERL||Summit Racing|
|Earl’s UltraPro PTFE -6 hose, 20-ft||682006ERL||Summit Racing|
|Earl’s 1/4-NPT to -6 AN black adapter fittings (2)||AT981606ERL||Summit Racing|
|Earl’s -6 straight Speed-Seal hose end (6)||AT600136ERL||Summit Racing|
|Earl’s -6, 90-degree Speed-Seal hose end||AT609236ERL||Summit Racing|
|Earl’s -6, 45-degree Speed-Seal hose end||AT604736ERL||Summit Racing|
|Holley 10-micron fuel filter, 3/8-NPT female||HLY-162-550||Summit Racing|
Photography by Jeff Smith