Upgrades are the backbone of what we do as car guys. No matter what brand of car you favor, we are all constantly looking for ways to improve our rides. Whether that upgrade is a camshaft or intake and carburetor swap, improving how our car or truck runs is the goal. But how many of us plan for future upgrades? I can’t tell you how many times I have seen an upgrade that was unceremoniously discarded after a short time because it didn’t work with another upgrade the car owner decided to include. One of the areas where this happens quite often is the fuel system.
There are an untold number of enthusiasts who would like to eventually upgrade their ride to include electronic fuel injection (EFI). There is no arguing it is a great upgrade for anyone. But, what some don’t realize is it takes various ancillary parts to make it all work. Unfortunately, buying all those parts at once can get expensive. So, with a budget in mind, many enthusiasts buy and accumulate parts when they can afford them. For instance, if purchasing a complete EFI kit at one time is out of your price range, why not start with a fuel system beforehand, That way, you’re ready at a later date?
The only problem with doing this is that the system you build now — while your car is carbureted — needs to be compatible with both the current carb and the future EFI. To find out how to create an EFI-ready fuel system that will work with a currently installed carburetor, we decided to talk to the guys at TANKS Inc.
One would think that upgrading the fuel system would be easy. You buy an EFI-capable fuel pump, plumb it into your fuel system and you’re ready. In reality, a carbureted system and an EFI system have different needs and requirements. For instance, a carbureted system only needs 6-1/2 to 8 psi of fuel pressure to sufficiently feed the engine. Many EFI systems require 45 psi or more. So, how do you make your fuel system EFI-ready but still utilize the carburetor?
It’s All Inside
The advent of in-tank fuel pumps has made fuel delivery in classic cars better than ever. No longer do enthusiasts need to rely on a mechanical or inline pump. For starters, a mechanical fuel pump would not feed enough pressure for EFI. That said, a surge tank is an option, but the cost is comparable to that of an in-tank pump. Also, you will have a “fuel tank” mounted under your hood. As far as an inline pump, while they are less expensive than an in-tank pump, it is critical that they are mounted close to and level with the bottom of the gas tank. Mounting them higher will cause poor performance and premature failure. They also have noticeable noise and vibration characteristics. If you are thinking about upgrading your fuel system, TANKS Inc. has several EFI-ready in-tank pump modules ready to go. As a bonus, they even have complete tank kits that include an all-new tank combined with a fuel-pump module already mounted inside.
Upgrading to a high-pressure fuel system while still using a carburetor will require a fuel pressure regulator. When purchasing one, you need to know there are two variations — a dead-head and a return style. Most EFI systems require a return line to reroute unused fuel back to the tank. However, most carburetor-dedicated regulators do not have a provision for a return line — this is a dead-head regulator. The problem with this is the unused fuel has no place to go and a lot of pressure builds before the regulator. This will cause the fuel pump to get hot, which drastically shortens its lifespan. By installing a regulator with a return system, the unused fuel is able to return to the fuel tank and your fuel will remain cooler as it is not “heated” by the fact it has hit a dead-end. A pump that is trying to move fluid but can’t, will not last as long as one that constantly sees recirculating fuel.
Once you have the fuel pump addressed, you need to get that fuel from the rear of the car to the engine. Many classic cars were equipped with a 5/16-inch fuel line. While this might have been adequate for a stock 327, 302, or 318, not so much for today’s upgraded mills. TANKS Inc. offers a complete fuel system (P/N: CARB-LINE-KIT) which includes 25 feet of hose (-6 AN which is comparable to 3/8-inch) and the fittings needed to connect the in-tank fuel pump to the engine.
Fuel System Regulations
When shopping for a bypass regulator, you need to make sure that you buy one that can keep pressures within the parameters needed to work with a carburetor. There are a couple of ways you can accomplish this regulation. One is to use the fuel pressure regulator in the CARB-LINE-KIT which is adjustable from 5 to 10 psi and is compatible with fuel pumps up to 250 lph. However, this configuration will require you to buy another regulator when the EFI is installed.
A second option is available from Holley. They have two regulators (P/Ns: 12-879 which uses 3/8 NPT threads or 12-880 which uses -6 ORB O-ring fittings). Each has a range of 4 to 65 psi. The regulators come configured as a high volume, low-pressure, unit but can be reconfigured to control high pressure simply by changing a spring in the regulator. This is designed for those currently running a carbureted system who plan to eventually upgrade to EFI.
But, when designing a system, does it matter what fuel pump you use? Of course, it does.
There is a myriad of fuel pump options available to enthusiasts, and knowing which one is right for your application can be confusing. According to Justin Somerville of TANKS Inc., “horsepower is the biggest factor when considering a fuel pump. A pump that will sufficiently feed an 800-horsepower engine that is carbureted, could also be rated to feed a 600-horsepower engine running EFI. The problem is, if you chose a pump that is “too large” for a given situation, it could overpower the carburetor, even with a good bypass regulator.”
Since pump selection is crucial, and so many factors need to be considered when selecting, the folks at TANKS Inc. thought it a good idea to give you some insight into selecting the right pump. In fact, you can check out their pump selection page by clicking here.
In a nutshell, the best way to select a fuel pump is to consider three factors:
- How much horsepower your engine will produce.
- What fuel pressure is required for your engine.
- How much voltage is supplied to your fuel pump when the engine is running.
Not only does an upgrade from a carburetor to EFI require a different fuel system and pump, but with the advent of late-model engines being swapped into many cars, an electric pump is also required. This is because, for starters, newer engines have no provision for a mechanical pump. By installing an in-tank EFI-ready pump, not only can you feed a carbureted engine, provided a bypass regulator is incorporated, but your ride is ready for that LS swap or an EFI upgrade when you are.
Another thing that Justin wanted to mention is fuel pump safety. “An electric fuel pump really should have some sort of switched-power control. A few examples of why, are the engine can stop running and the pump continues to run. Or in case of an accident, the pump should know to stop running.” We found this Safety Switch and Relay kit that will not only provide a continuous supply of voltage, but it also features an oil pressure safety switch to turn the fuel pump off in the event of oil pressure loss (i.e., the engine stops running).
Although the fuel system is not something many spend much time thinking about, it should be. If you plan to eventually make the switch to EFI on your classic, now might be the time to focus on securing a fuel system that will meet the needs of your current induction and the future fuel injection you know you want.