Fuel’s Gold

Jun 30, 2010

It’s a simple premise. The fuel system of an automobile doesn’t entail much more than fuel going into a storage device and then being moved, via some sort of pump, to the induction assembly. And yes, there are important stops along the way.

If you’ve ever wondered what all goes into a fuel system or, maybe more importantly, how your shop could profit from selling fuel delivery products, then you’ve come to the right place. Let’s follow the fuel with the help of our tour guides-fuel system products professionals who know the insides and outs of these components.

Jesse Powell from Aeromotive starts with an absolute: “One thing to remember when it comes to fuel systems is that a good fuel system will not make power. It can only support power. However, if a fuel system is not adequate, it can rob horsepower and in some cases even lead to total engine failure. This is why it is so critical to understand your application and choose a fuel system designed to meet the performance demands of your engine.”

Elie Nahed of Mallory and ACCEL Digital Fuel Injection agrees. “Today’s high-tech, high-horsepower engines require a fuel system that is equally high-tech to supply the engine with the proper fuel flow to be able to generate and maintain all that horsepower.”

Follow the Fuel

David Barker of XRP starts the explanation of a fuel system.

“As for a basic flow, everything starts at the tank. This is either a fuel cell, a crashworthy container used in hardcore off-highway racing environments or a fuel tank, as found equipped on most passenger vehicles and on highway applications. The fuel enters the tank or fuel cell through the filler neck, either a vented or non-vented device.”

Fuel has two options for getting to the induction assembly. It can be moved by a mechanical fuel pump, usually mounted on the engine, or an electrical fuel pump that can be mounted just about anywhere including inside the gas tank.

But there’s another factor: basic physics. Pumping a fluid is not an equal-sided process. Barker explains.

“This is one of the key points of fuel system problems. People often don’t realize just how vulnerable a fuel system is to the pump suction side problems. All types of pumps generally push fluids very well, but their weakness is on the suction side. They are great pushers but poor suckers!”

For that reason, most performance fuel systems-when racing rules allow it-will run with the fuel pump located close to the fuel supply.

“Because pumps have their difficulty on the suction side, the closer the pump can be to the fuel itself, the better the pump is going to work,” says Barker. “This is exactly why many vehicle manufacturers today put the fuel pump right inside the tank itself. Any line or hose that leads from the tank or fuel cell to an externally mounted pump is going to have some degree of flow resistance and the longer the line or hose, the greater the resistance. Because an internally mounted pump is more difficult to service or to clean the intake screen, most racing applications find the pump mounted outside the fuel tank. We still want to keep the pump as close to the fuel source as possible and the supply line as large as possible going into the pump to keep the flow resistance to a minimum.”

That advice helps eliminate an old problem for carbureted engines.

“This used to be a cause of a common vapor-lock problem on the older carburetor engines,” he continues. “A pump would be mounted a fair distance from the fuel tank and a line was often used that was smaller than it should have been. As the fuel was sucked, a vacuum formed in the fuel supply line from the long line resistance. Since a fluid’s boiling point varies as to the pressure or vacuum on the fluid, under a high vacuum condition caused by a long, small-diameter fuel line, when the heat around the line was hot enough the fuel would boil in the line or the suction side of the pump, causing cavitation and thus the vapor lock.”

Size Matters

With such importance, Robbie Ward from MagnaFuel says, “The fuel pump is the heart of the fuel system. When adding more horsepower or a power-adder you need to have enough fuel delivery to support the power. This is a situation where more is better. Over-sizing the fuel pump to some degree is best.”

The history of fuel pumps has changed. Powell from Aeromotive says, “Since 1986, most cars produced have been EFI. The adoption of EFI changed the landscape of performance fuel systems.”

Before fuel starts its journey, there is one very important stop to be made: fuel filters.

“Fuel filters are the most overlooked part of the fuel system,” Ward says. “Having too fine of micron filter before the fuel pump can hinder its ability to flow. Proper sizing of fuel filters is a necessity. You need one fine enough to catch debris downstream, but not so fine as to cause a restriction.”

Barker adds, “Before the fuel is sucked into the pump, it is usually screened or filtered in some manner to protect the pump from any contamination that may exist in the tank. This contamination could be internal tank debris from a deteriorating inner surface of the tank, or dirt that gets into the tank from a refueling operation or off-road or dirt-track racing. This is one of the key points of fuel system problems.”

Nahed from Mallory and ACCEL adds, “Always use a primary and a secondary filter. The primary filter (40 to 100 microns) will keep any large contaminants from entering the inlet side of the fuel pump and a secondary fuel filter (5 to 20 microns) will keep any small contaminants from entering your carburetor or fuel injectors.”

With a fuel filter and pump in place, the next piece to the puzzle is controlling the flow.

According to Ward, that requires one smart part. “The regulator is the brain of the fuel delivery system. It needs to control the fuel pressure but not restrict the flow. The regulator has to compensate for needle and seat opening on carburetors and injectors opening on an EFI system. It has to instantly change to keep the pressure as stable as can be to keep from affecting performance.”

Connecting the tank/cell, pump and regulator is the actual fuel line. Nahed gives us a good baseline.

“Most vehicles come with 3/8-inch line from the factory, which is more than adequate to support a naturally aspirated engine up to 600 hp. Nitrous or boosted applications making the same horsepower will require a 1/2-inch fuel line due to a higher BSCF (brake specific fuel consumption). That also goes for naturally aspirated engines making over 600 hp. And always remember that the fewer 90-degree turns for lines in the system will help with better fuel flow.”

Gas ‘n Go

With all these precision parts, there is definitely money to be made in fuel delivery system upgrades.

“There is a real opportunity with performance fuel systems, mostly due to their necessity,” Powell says. “Plus, the margins have remained fairly good on these types of components, making it a profitable line to carry.”

Along with what’s on the shelf, your professional expertise can be a determining factor for making the sale.

“One of the most important things that you can provide your customer is information,” he continues. “Reminding them when they buy a turbo kit that there is a good chance they need to upgrade their fuel system. This seems obvious and small, but it can go a long way. The other side to this is being able to make recommendations that make sense and putting the right product in their hands the first time. Fuel systems can be complicated, and understanding every aspect might not be necessary, but contacting the manufacturer before you make the sale will go a long way.”

And don’t forget the accessories.

“Retailers need to stock the support equipment for a great fuel system,” Ward says. “Having the parts to finish the job completely enables them to sell more equipment because it’s needed. Fittings, fuel lines, filters and gauges are all necessary parts to complete a fuel system.”

And Barker adds, “In order to have profits in a speed shop, you have to have a repeating and satisfied customer base. Most of the performance users are not going to do a one-time build or modification and be done with it. We in this industry are tinkerers. We often get something done and then we decide to make changes or try something different. It is very competitive in the performance marketplace for a speed shop with a store front and overhead to compete with the online and mail-order houses. A speed shop that is going to service that customer must have a knowledgeable staff that understands the products and inventory. That is something the online and mail-order houses have a difficult time with.”

Having the correct parts available also helps.

“A speed shop that is going to be successful in plumbing has to make a commitment to have a large inventory of it on hand and be able to know what is available to satisfy the odd requirement,” says Barker. “A customer that needs 10 or 15 items but can only get 6 or 8 of them is not going to be very happy having to go shop around for the parts he cannot get. Once he finds the speed shop that can fill his needs, that shop will become his first visit next time he is buying.”

And finally, understanding the capabilities of a customer’s current system is important to finding the areas that need improving.

“Most speed shops take the customer’s word that the fuel system on their vehicle is adequate for the upgrades that the shop is about to do,” Nahed says. “We always hear how they read an article or how their buddy still uses the stock fuel system on his 700-hp daily driven car.

As a speed shop, it is up to you to do the math and show your customer firsthand that his or her fuel system is not adequate to support the horsepower for the upgrades that are about to be done.”

Strong Links

As far as why offer fuel systems, Nahed says, “You should offer your customers a proper fuel system or system components to complete their performance buildup or engine upgrade while you are estimating the job. Your customer relies on your knowledge to point them in the right direction. If your customer picks up his or her vehicle and finds out that you failed or forgot to address the fuel system, which is now causing issues, you will not only have lost an opportunity to maximize your profits, but now might have lost that customer to a competitor-not a good thing to happen in today’s dog-eat-dog marketplace.”

Powell notes, “When it comes to knowing what to stock or what to sell, it’s important to think past just the fuel pump. A fuel system is like a chain-only as good as its weakest link. A pump needs the right filters, lines sizes, tank or cell and fuel pressure regulator. Making sure these components all speak the same language is critical. If you can offer a consumer a complete package, or at the very least matched components, then you have a chance for a happy consumer likely to bring repeat business and an increased sale.”

An important thing to keep in mind is improved fuel delivery is critical to a successful performance upgrade.

“You cannot make horsepower without fuel. Everyone that is upgrading performance is a candidate for a fuel system upgrade,” Ward says.

And Barker adds, “Fuel systems are one of the easier and more popular modifications to make or change. Performance users and racers will often change over from one system idea to another. Filters that are easy to clean can be put into an existing system very easily and quickly and are very popular sellers. From a custom look standpoint, the fuel system is what shows up all over the top of the engine and that is what many enthusiasts want-to look very high-tech on their engines.”

If nothing else, it’s fuel for thought.