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FUELING THE FIRE—Mapping out a fuel system with Holley and Earl’s


Written by Derek Putnam

Photography By The Author and Courtesy of the Manufacturer

It’s natural to always want more, but sometimes too much of something isn’t a good thing. For example, using a camshaft or cylinder head that’s too big for your engine combination can result in lackluster performance and some serious head scratching. But there are areas in the automotive world where too much can be okay, and going big on a vehicle’s fuel system can earn a check mark versus a head shake. But before allowing yourself to think a Dominator carburetor is the ticket to more performance on a 400 horsepower small-block, cool your jets. By going big on the design of a fuel system and picking the right fuel pump and sizing the fuel lines correctly, the ability to change engines and still have room to grow into more power is achieved. As an added bonus, not taxing out any part of the fuel system keeps the amount of heat generated to a minimum.

Having roots dating back to the late 1,800s for tinkering with engines, Holley is credited with being one of the four original suppliers to Ford Motor Company. That dedication led to the introduction of the now-common 4150-series four-barrel carburetor in 1957, as well as the “blue” electric fuel pump that gained cult-like use starting in the early 1970s. Today, Holley stands as one of over 20 brands under a single umbrella, with over 300 part numbers in the fuel pump and regulator segment alone. That can easily lead to confusion over what parts to choose for a fuel system, but with Blane Burnett from Holley and Jason Rollins of Rollins Automotive Speed and Custom in our corner, we can attempt to tackle the mysteries of fuel systems.

Choosing a pump for your fuel system can be easy but difficult at the same time. Lots of factors can come into play, and each one will affect your viable options. For example, some power levels and the flow rates needed to support them can eliminate most mechanical pumps, but now you’re faced with choosing from dozens of electrical pumps. Do you use an in-tank pump or an externally mounted one? Do you try to integrate it with an existing fuel system, or construct an entirely new one for better results? Will the pump only handle your current requirements or does it give you room to grow? And since E85 is becoming a popular choice, does your pump support the corrosive properties of this fuel? Holley has over 120 different pumps to answer those questions, and we selected part number 12-1800 from Holley’s Dominator line. Able to support 1,800 horsepower on EFI applications or 2,100 horsepower on carburetor-fed engines, and work with a variety of fuels including E85, this pump will allow us to increase power levels over time while keeping the same fuel pump.

“The key to understanding fuel systems is identifying your key factors,” said Rollins. “You need to establish the type of induction system, projected horsepower, and how the vehicle will be used.” With that knowledge in hand, a game plan can be designed. “You want to consider the type of fuel system the vehicle already has on it,” said Burnett, adding that will influence what pump options exist. “It may be easier to purchase a pump rated for higher horsepower that is a factory drop-in replacement unit that requires no modifications to the rest of the system for installation.” But in our case, a complete revamp of the system and possible four-digit power in the future meant selecting a pump that can handle a lot of load.

“Holley’s Dominator pump is designed with two separate veins/motors, so it can be set up to accommodate different needs,” said Rollins. “You could run one side for daily driving, or pit use only for a race car if needed. This will keep the heating of the fuel down versus using both when the volume isn’t needed. The second motor/vein can be routed to a toggle switch, a boost-referenced switch, a wide-open-throttle switch or even an ECM trigger when running fuel injection to bring it in.”

With the fuel pump selected, the next step is to map out how the fuel system will be run. Keeping fuel away from heat and moving parts might seem easy enough, but doing it without excessive twists and turns in the fuel’s travels from the tank to the engine can be difficult.

“Hard 90-degree forged fittings are sometimes a necessity in the tight confines of an engine bay, but they should rarely be used due to the flow restriction,” Burnett admits. “Compared to a 90-degree tube fitting, a hard 90-degree forged fitting is like adding eleven feet of line to a fuel system. Using fittings that require less changes in direction and take the least hard angles is always the way to go.”

The next decision is whether to use a return-style system or a return-less version, and while Burnett believes it is personal preference, Rollins normally goes for a return-style set-up.

“I’ve seen more consistent fuel pressures on a return-style system, especially with carburetors,” Rollins admits.

Choosing the correct line and size can be a common problem as well, and operating pressure and fuel choice will dictate your parameters.

Filters are an important part of fuel systems that can be overlooked, or not added to the system correctly. Running a filter before the fuel pump, as well as another after it, will help ensure fresh fuel makes its way to the carburetor or fuel injectors. It’s also important to keep an eye on length of time a filter has been in the system, especially with corrosive fuels like E85.
“For modern daily drivers, the best thing is to keep using your vehicle,” said Blane Burnett. “The problems start when vehicles like race cars are stored and fuel systems are not drained, cleansed and stored properly. It pays to be on top of maintenance when running those types of fuels and when the vehicles may not be used for extended periods of time.” The breakdown or corrosion of filter elements, hoses and other parts of your fuel system can find their way to the regulator, or worse yet your engine, possibly creating damage that far outweighs a simple filter element change. We added Holley’s 100-micron filter just before the pump (part number 162-572), and complemented it with a 40-micron filter (part number 162-571) between the pump and the regulator.

“Typically anything under 600 horsepower can be adequately supplied by -6 AN or 5/16-inch line,” said Burnett. “Above that mark, it is common to upgrade to -8AN.” But choosing E85 as a fuel choice will shift those recommendations. “All things being equal, an engine that that uses E85 requires 30 percent more fuel to supply the engine over traditional gasoline,” said Burnett. Fuel injection and boosted applications also raise fuel line requirements, and going to a slightly larger line is better than restricting the system’s ability to function.

“BSFC, or Brake Specific Fuel Consumption, is why fuel pumps are rated differently for EFI and boosted applications over a naturally aspirated carbureted one,” said Rollins. “Boosted and EFI systems can require 10-15 percent more fuel volume, and that requirement should also be figured into line selection.”

Building a turbocharged powerplant with a target goal of 850 horsepower as a starting point, Rollins wanted to build a fuel system that would not only handle the engine’s initial power level, but also be able to move beyond it.

“You need to look beyond your current status and not build a system that could be obsolete in a year,” said Rollins. “Doing a fuel system can be tedious, so taking a little extra time to make sure the right components are used, the right amount of line to cover it, and all the different fittings needed can mean the difference between an easy day and pulling your hair out. Even if you’re starting from scratch, the right parts and a clear vision means a system can be assembled in just one day, even if it’s on jack stands in a driveway.”

With the car on a lift, Jason Rollins starts removing the existing fuel pump, lines, filter and wiring. It also gave us a chance to clean up all the burnout and tire residue from years of abuse.
After stripping the car of its old fuel system lines and filter, determine if duplicating the pump mounting location and existing lines or mapping out a new pump and line location set-up is the better choice.
Holley’s Dominator fuel pump gets a permanent spot on the frame rail with an aluminum plate for support. Each end of the pump receives an Earl’s -10 AN ORB fitting to connect it to the lines and pre-pump filter.
With the fuel pump in place, Rollins added Holley’s 100-micron filter just before the fuel pump, which required a pair of -12 AN to -10 AN ORB fittings to work with the lines and pump.
To complete the connection between the fuel cell and the filter, Rollins used a two-foot section of Earl’s Premium braided hose in -10 AN size with a 90 degree -10 AN fitting on the cell, and a 45 degree -10 AN fitting on the filter.
The existing fuel pump relay and wiring was cracked and past its prime, so Rollins used a 40-amp relay and wiring kit from Big End Performance (part number 52010) to complete the circuit.
Cutting and assembling braided line can be intimidating, but Jason Rollins took the time to show us some tips on how to do it right. “You want to use a vise with a special set of inserts that are designed to hold fittings,” Rollins said. “After marking your cut location with household tape or black electrical tape, use a cutoff wheel to slice through the line.” The small particles that are left from the cutting can be blown out with compressed air, or as Rollins prefers, brake cleaner. Once the line is clean, start assembling the fitting by putting the slip collar over the end of the hose to where the bottom of the threads inside the collar is even with the end of the hose. The second step should involve a lubricant or anti-seize to install the fitting into the sleeve, and Rollins prefers the latter. “You want to start the fitting by hand,” he says. “If it won’t start by hand, the hose may be too far into the collar. As you continue tightening the fitting into the collar, watch the hose to make sure it’s not getting pushed out by the fitting.” After getting everything started, move to a wrench to finish the process.

Rollins was then tasked to finish the rest of the lines to complete the system and ran Earl’s -10 AN line up to the regulator to supply the fuel and Earl’s -8 AN line to return the leftover juice to the tank.
The final step was finding a good spot for the Holley 40-micron filter to call home. Rollins used a flat spot on the frame rail that was away from heat, and used a zip-tie to temporarily hold the filter in place (a clamp replaced the zip tie).
An engine build normally doesn’t happen without an intended use or vehicle in mind to accept it, and after building mostly naturally aspirated, nitrous, and even a few supercharged engines, Jason Rollins was ready to switch gears and try his hand in the turbocharged arena. But he didn’t want to change up the combination in his ’71 Nova, so the shop ’67 Chevrolet Camaro will start a new chapter for its thirteenth year of ownership. Purchased by Chip Rollins in 1987, the car housed a few different big-block combinations for bracket racing before becoming a test bed for Rollins’ first Procharger engine build several years ago. The car is currently powered by a pump-gas 383ci gen-one small-block that the author has used to win a few events at Gainesville Raceway. That engine will make way for a turbocharged build based on the popular 5.3 LS platform, and the estimated 850 horsepower will put the new fuel system Rollins just constructed to the test. The build will be documented on the pages of Fastest Street Car magazine, and Rollins plans to collect low 9-second time slips at close to 150 mph.



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