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Building a Fuel System for a 630hp Twin-Turbo Small-Block Engine

Feeding The Beast: Competition Specialties uses Holley Performance products to fuel a twin-turbo small-block

Chuck Vranas May 30, 2018
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One of the most important facets in setting up your performance car with a hopped-up V-8 is making sure that all of its systems interact well when it comes time to doing their jobs. From selecting the right cam and cylinder heads to ignition and induction, it’s all about getting the right formula that will earn you the most horsepower and bang for your buck. You can assemble a truly wicked engine, but without delivering enough fuel your performance will surely suffer.

On a recent visit to Competition Specialties in Walpole, Massachusetts, shop owner Peter Newell was mapping out a new fuel system to support the latest engine combination in his ’68 Camaro. Having updated the car with a fierce 630hp twin-turbo 350ci small-block spinning a pair of Nelson Racing Engines 61mm mirror-image turbos at 9 psi of boost, the layout would need to flow just the right amount of fuel to meet his needs.

Starting out back with a fresh fuel tank from Summit Racing, the system moves toward the front of the car and includes the pre-pump and post-pump filters, pump, relays, regulator, and carb along with proper fuel lines and fittings. It’s a great idea to draw up a simple schematic diagram to illustrate your needs and measurements for everything from system placement to line routing and fitting needs.

With a plan in place, he contacted Holley Performance to incorporate their line of cutting-edge products into the new system, including their exclusive fuel pumps and regulators, a Quick Fuel Technologies carburetor, and Earl’s Performance plumbing (lines and fittings).

Regardless if you need to outfit your small-block, big-block, LS, or any other engine combination they’ve got you covered. Since the engine incorporates twin turbos, it’s imperative to feed it the correct amount of fuel regardless if it’s for normal driving or under extreme demand. To accomplish this, Newell selected Holley’s 160-gph Dominator in-line billet fuel pump (PN 12-1600-2) with dual inlets, capable of supporting up to 1,600 EFI or 1,800 carb horsepower. The twin-pump design allows for the use of both pumps to be wired simultaneously or independently where the second pump can be activated to support the demands from power-adders such as boost or nitrous. Hence, you can use one pump for cruising and activate the second pump when building boost or adding nitrous. Newell independently wired his pumps using twin 30-amp fuel pump relay kits (PN 12-753, x2) from Holley. Other key components include selecting just the right Holley fuel filters and regulator as well as a Quick Fuel Technologies carb to handle the job. Let’s follow along and take a deeper look into setting up a system to accurately support your fuel system needs. CHP


1. To lay the groundwork for a perfect fuel system you’ve got to start with the basics, including fuel line, fittings, and clamps. Earl’s Pro-Lite 390 Series hose comes in various sizes to fit your application needs and works perfectly with matching black-anodized aluminum AN fittings.


2. The heart of the fuel system relies on delivering clean fuel to the engine for ultimate performance. Holley’s 160-gph Dominator in-line billet fuel pump (PN 12-1600-2) with dual inlets pushes enough fuel to support up to 1,600 EFI or 1,800 carb horsepower. Matched with 260-gph billet Dominator 100-micron fuel filters (PN 162-572), it delivers the ultimate punch.


3. Since the fuel pump is a dual-inlet model there will be two filters mounted between the tank and the pump and one filter mounted after the pump. Newell used Holley’s black billet mounting brackets (PN 162-574) to get the job done to the inside of the framerail for a nice, clean installation.


4. With the post-pump 260-gph billet Dominator 10-micron fuel filter (PN 162-570) mounted and AN O-ring fittings in place, it was time to measure the length of #10 fuel line needed from the filter to the regulator.


5. After determining the length of fuel line required, it was cut to the desired length and prepared for assembly. With the AN fitting apart, the end was then pushed onto the line.


6. The threaded end was lubricated and set in place, hand-tightening it first.


7. The fitting was then tightened using a pair of wrenches until complete.


8. Once the lines were completed, they were set into place. The fittings were then lubricated and hand-tightened to the fuel filter. Always follow the directional flow noted on the filters from the tank to the carb.


9. After tightening the fittings until snug, you can see how nicely the lines are laid out and fastened in place to the inner framerail, including the return line to the gas tank.


10. Once an area to locate the pump was selected—allowing ample room for lines and pre-filters—it was secured in place. Make sure the pump outlet faces forward following the arrow on the pump body. Note that it must be located to the rear of the car even with or below the bottom of the tank.


11. Carefully thread the recommended -10 AN O-ring sealed fittings to the inlet/outlet ports of the pump using ones such as PN AT985010ERL for the application. Then torque to the recommended specifications.


12. The fuel pump main fuel feed line was then secured in place to the pump outlet.


13. For ease in serviceability and a clean installation, Newell used a weatherproof electrical connector when wiring the fuel pump.


14. Here you can see just how well balanced the installation of the fuel pump, pre-pump filters, and lines came out once completed.


15. Holley’s four-port VR-Series Fuel Pressure Regulator for carbureted applications, machined from 6061-T6 billet aluminum for strength and durability, can support 3,000-plus horsepower and is adjustable from 4-9 psi base pressure.


16. The four-port version of the regulator features -10 AN O-ring inlets and -8 AN O-ring style returns. Using Earl’s exclusive AN adjustable wrench, the fittings were installed to the regulator.


17. Here’s the completed regulator ready for installation to the fuel system.


18. Once the location was determined, the regulator was mounted to the firewall using the supplied bracket. Always check the reverse side of the firewall to be sure the mounting points will not interfere with another existing system.


19. All the fuel lines were then connected to the regulator.


20. For moving plenty of fuel to feed the twin-turbo beast, a Quick Fuel Technology Q-Series 850-cfm Blow-Thru Annular Booster carb (PN Q-850-BAN) takes on the task. After placing the base gasket, the carb was lowered onto the intake and secured in place.


21. Earl’s annealed 3/8-inch aluminum tubing was shaped using a standard Blue-Point TBS300 tubing bender combined with Earl’s AN fittings to create the dual inlet fuel line.


22. Newell then installed the custom dual-inlet fuel line to the carb.


23. Here you can see a close-up of the fuel line installation, showing just how clean and balanced everything looks.


24. The throttle linkage was then connected to the carb, completing the installation.


25. An Extreme Velocity blow-through carb hat was then bolted into place.


26. This 15-gallon Jaz Products aluminum fuel tank, constructed out of 5051 aluminum, from Summit Racing is TIG-welded for extra strength and was a perfect choice for the application.


27. The Jaz Products tank is safety foam filled and comes complete with a flush-mount cap assembly and sending unit, making it perfect for custom installations.

Photos by Chuck Vranas


Competition Specialties
Summit Racing
Akron, OH
Bowling Green, KY 42101



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