AEM High Volume Fuel Rails are CNC machined from 6061 T-6 billet alluminum and feature a 1/2 inch fuel bore capable of flowing enough fuel to support most high-performance engines. This larger bore also dampens the back pulse created by oversized injectors in high-output applications. The AEM fuel rail also works perfectly with stock injectors. Each fuel rail includes an additional port for the installation of a nitrous set-up or external fuel pressure gauge. The ends of the fuel rail are tapped to accept either -6 or -8 line and a custom fitting allows for the use of the stock fuel hose. AEM's High Volume Fuel Rail kit includes new injector o-rings, fuel line fittings, comprehensive installation instructions and AEM decals.
Key Features:No additional parts required. Specifically engineered for each application. Available in blue, red and silver with laser-eched graphics, for show quality look. Manufactured and assembled in the USA.
AEM High Volume fuel rails feature a 1/2-inch fuel bore to support fuel flow for applications up to 1,000 horsepower. This large bore also dampens backpressure pulses created by larger injectors and works perfectly with stock injector sizes. An additional 1/8th NPT port is included to accommodate a nitrous set up or fuel pressure gauge. A custom fuel line fitting is included for the factory fuel line, and the ends of each rail are pre tapped to accept -6 AN or 9/16”x18 fittings for users who want to use custom fuel lines.
No additional parts required for installation
Specifically engineered for each application
Manufactured and assembled in the USA
O.E. fuel pressure regulator or AEM adjustable fuel pressure regulator mounts directly to rail with no modifications
Comprehensive installation instructions, hardware, fittings and injector O-rings included
Will AEM Fuel Delivery components void my new car warranty?
A:
NO. The only time this can happen is from improper installation that causes damage to a vehicle system. If a service technician denies your warranty claim ONLY because the car is modified with an AEM fuel delivery component and the vehicle system failure was not a direct result of the installation and use of an AEM fuel delivery component, please refer him to the Magnusson Moss Warranty act. You can download the Magnusson Moss Warranty act from SEMA’s website at: http://www.enjoythedrive.com/san.
The Fuel Rail on gasoline is capable of flowing for over 1000 HP. The Fuel Filter on gasoline flows for 500 HP and the Fuel Pressure Regulators flow to the limit of the fuel pump, so its flow capabilities are governed by the fuel pump. We have run our regulators in 1,800 HP drag cars with no issue.
What is the warranty on AEM High Volume Fuel Delivery components?
A:
Advanced Engine Management Inc. warrants to the consumer that all AEM High Performance products will be free from defects in material and workmanship for a period of twelve (12) months from date of the original purchase. Products that fail within this 12 month warranty period will be repaired or replaced at AEM’s option, when determined by AEM that the product failed due to defects in material or workmanship. This warranty is limited to the repair or replacement of the AEM part. In no event shall this warranty exceed the original purchase price of the AEM part nor shall AEM be responsible for special, incidental or consequential damages or cost incurred due to the failure of this product. Warranty claims to AEM must be transportation prepaid and accompanied with dated proof of purchase. This warranty applies only to the original purchaser of product and is non-transferable. All implied warranties shall be limited in duration to the said 12 month warranty period. Improper use or installation, use for racing, accident, abuse, unauthorized repairs or alterations voids this warranty. AEM disclaims any liability for consequential damages due to breach of any written or implied warranty on all products manufactured by AEM. Warranty returns will only be accepted by AEM when accompanied by a valid Return Merchandise Authorization (RMA) number. Credit for defective products will be issued pending inspection. Product must be received by AEM within 30 days of the date RMA is issued.
If you have a warranty issue, please call (310) 484-2322, extension 203 and our customer service department will assist you. A proof of purchase is required for all AEM warranty claims.
In naturally aspirated applications where “bolt on” performance items are used the fuel delivery system including the fuel injectors do not have to be upgraded. When items that greatly enhance the power of the vehicle are added the stock fuel delivery components are not up to the job. The most accurate way to determine the fuel needs of the engine is to determine the anticipated power level of the engine and size the fuel delivery system accordingly. Here is an excerpt from our “Fuel Injection Basics” book supplied with our Plug & Play programmable Engine Management System:
Fuel Delivery System Requirements
Adequate fuel delivery is generally the greatest problem that we have encountered when tuning and calibrating EFI systems. We cannot stress enough how important it is to have adequate, consistent fuel pressure, and volume to the injectors. The use of a properly sized fuel line from the tank, fuel rail and return hose is imperative. Measures must be taken to eliminate excessive pulsations in the fuel rail so the injectors get even fuel flow. These instructions will review the entire fuel delivery system in the following section to help you design your own comprehensive fuel delivery system. On vehicles using the PNP version of the AEM EMS, all of the essential elements for adequate fuel delivery are designed into the stock fuel system. If you are using a PNP system on a vehicle that is heavily modified (forced induction, nitrous oxide, etc.) pay close attention to the following information regarding fuel delivery, as the OE fuel delivery system may not be capable of supplying an adequate amount of fuel.
Fuel Tank or Fuel Cell
In most cases the stock fuel tank is acceptable for street use. Most OE fuel tanks have internal baffles to reduce fuel slosh in the tank, which reduce the chances of intermittent fuel delivery.
Fuel cells are the best means of fuel storage because they eliminate the chance of fuel slosh by using a foam liner that dampens the fuel travel. Fuel cells also have the fuel pick up placed in a position that is at the lowest portion of the tank—or in the case of a drag racing car—in the rear of the tank where the fuel shifts to during acceleration.
In either case, the tank must be vented to provide air for displaced fuel as the engine consumes it. The tank must also have provisions for fuel return. It is important that the fuel return be placed as far away from the pick up as possible to prevent foaming or bubbles at the inlet.
Fuel Pump Sizing
To achieve proper fuel delivery, you must select the right fuel pump for your vehicle. In most cases, where the engine has been modified only with “bolt on” performance items, there is rarely need for a larger fuel pump or larger injectors. Vehicle manufacturers typically design a “safety factor” into the fuel pump to accommodate the deterioration of the fuel system over time. This safety factor is intended to compensate for a fuel filter that is nearing the end its life, or for deposits in the injector orifice. Our research has revealed that generally there is about a 15%-20% oversize in most factory fuel pumps.
If the engine is enhanced via forced induction or nitrous oxide, the stock fuel pump is inadequate. If the engine’s power is increased more than 15-20% fuel delivery must increase as a factor of the power gain.
The way to determine the proper-size fuel pump is based on the desired brake specific fuel consumption (BSFC) of the engine. This term refers to how much fuel in pounds per hour (pph) the engine consumes per horsepower and is a measure of the efficiency of the engine. It is a useful term in determining the total fuel requirement of the engine.
On vehicles equipped with forced induction or nitrous oxide, higher BSFC’s are required as an added measure of safety to prevent detonation or high combustion chamber temperatures. Below is a guide of BSFC’s with standard CR that AEM uses for various engines that run on gasoline:
• Naturally Aspirated engines have a BSFC of .48 to .50
• Forced Induction engines have a BSFC of .65 to .68
Methanol (alcohol) powered engines require twice the amount of fuel so the BSFC’s are doubled.
Calculating the total fuel requirement of an engine requires simple equations that we outline in the following section. You must know how much power the engine is anticipated to make and we recommend that you guess on the high end. The fuel requirement will be determined in pounds per hour of fuel flow. Since most pumps are rated in gallons/hour you must know the weight of your fuel/gallon. (The vast majority of gasoline based fuels run at 7.25 lbs./gallon.)
The equations to determine your fuel requirement is as follows:
• (Power x BSFC) x (1 + Safety Margin) = pounds/hour
• Pounds/hour / 7.25 = gallons/hour.
An example of this equation is:
• 500 hp gasoline engine using moderate boost with a 30% safety margin
• (500 x .625) x 1.30 = 406.25 lbs./hr.
• 406lbs/7.25 = 56 gallons/hour.
• If the pump that is being considered is rated in liters per hour, use the conversion factor of 3.785l/gallon. The pump described above would be rated at 56 gallons x 3.785 liters = 211.96 liters/hour.
In the fuel pump sizing, always use a safety margin greater than 20%.
Fuel Pump Location
The fuel pump should be located at a level that corresponds the lowest part of the fuel tank. This does NOT mean that the pump should be in a vulnerable position such as hanging below the tank. The pump should also be positioned so that it is protected from the road hazards (speed bumps, curbs, road debris etc.). In the event of an accident, the vehicle structure around the fuel pump should not deform to a point where the pump and its electrical connections are compromised.
The wiring for the fuel pump MUST be rated for the amperage of the pump. As with all high current wiring, a fuse rated for the amperage of the pump should be used. It is always better to err on the large side for the wire size. The ground for the pump must be the same size as the power lead and be mounted to a location that is clean and clear of any undercoating or paint.
Fuel Injectors
The AEM EMS requires the use of “saturated” or high-impedance fuel injectors. If “Peak and Hold” or low impedance injectors are to be used, an injector resistor must be used or you will damage the ECU. Resistors can be purchased from AEM. The PNP version of the AEM EMS is configured for the stock injectors and no additional parts are required.
To determine the size of the injectors, the total engine power must be estimated or known. The fuel pump calculations and BSFC information mentioned in the previous section provides a good understanding of the fuel requirements for an engine. The following equation will allow you to determine the requirements of your injectors:
Using the same engine as above:
• ((Power x BSFC) x (1 + Safety Margin))/Number of Injectors = pounds/hour
An example of this equation is:
• 6 CYL. engine rated at 500 hp on gasoline using moderate boost with a 15% safety margin on the injector
• 500 x .625 = 313 lbs/6 = 52 lbs/hr/ injector. 52 x 1.15=60lbs/hr/ injector
If we take the flow of the injector (60 lbs/hr) and multiply it by the number of cylinders (6), we arrive at a total of 360 lbs/hr of flow. As you can see, the fuel pump described above has enough capacity to feed the engine with a little room to spare.
It is a good idea to know the maximum operating pressure of the fuel injectors. In some cases the fuel injector will not open if the fuel pressure exceeds the design limit of the injector. Also, at the higher pressures the injector fuel flow may become non-linear and cause inconsistent fuel delivery, usually creating a lean condition. Most injectors can withstand up to 70 psi. Many of the pintle style injectors can withstand higher pressure.
In the fuel injector sizing, always use a safety margin between 15-20%.
Fuel Hoses & Routing
Even with proper injector and fuel pump sizing, a fuel system will not flow adequately unless the hoses that deliver the fuel to the fuel rail are of sufficient size and are routed properly. On systems that use the PNP version of the AEM EMS, there is no need to replace the fuel delivery hoses unless the engine is heavily modified.
NEVER route fuel hoses through the interior of a car. Put bluntly, this is a dangerous thing to do. Whenever possible, use a delivery tube to make the connection from the pump discharge to the filter in the front of the car. The lines should be rated to withstand at least twice the maximum pressure of the EFI system.
Using the above parameters of our sample engine with moderate boost, we expect to see pressures in the 65-70 psi range. This will require a line with at least 140-psi rating (most AN hoses exceed this by a large margin). When routing fuel lines, it is imperative that they are protected from road hazards and the exhaust system. The fuel line should NEVER be routed near battery cables. Use clamps to secure AN hose every 15 inches, or 24 inches if a rigid tube is used.
The following table will help you determine which hose size is correct for your application: These sizes are based on a nominal fuel pressure of 40 psi.
Fuel Delivery Hose Sizes
Gasoline Powered Engines
Up to 499 HP .344” hose -6AN
500 - 799 HP .437” hose -8 AN
900 – 1100 HP .562” hose -10 AN
Methanol Engines
Up to 499 HP .437” hose -8 AN
500 - 799 HP .562” hose -10 AN
900 – 1100 HP .687” hose -12 AN
The above table should be used for typical passenger car applications. However, for custom applications the hose run length will affect fuel delivery. If you have a long hose run, then the actual flow will have to be determined by running the fuel pump into a graduated cylinder, then measuring the flow vs. time and calculating the flow in gallons per hour (g/h). Also note that if fuel banjos are used in the system be sure they have adequate fuel flow capability.
The fuel return hoses should be one size smaller than the delivery hose. For the sample engine described above, we would use a .437” (- delivery hose and a .344” (-6) return hose.
Fuel Filter and Fuel Rail
Often overlooked in EFI installations, the fuel filter must have the capacity, filtering efficiency and burst strength to withstand the pressures of an EFI system. It must be able to flow the amount of fuel that matches the maximum fuel pump output. The filter is always located after the fuel pump, however it does not matter if it is positioned in the front or rear of the vehicle (we prefer to put it toward the front for easy serviceability). AEM carries fuel filters for high-powered engines, which use an easy to find, high volume, replaceable element.
It is imperative that a pre-filter be mounted to the fuel pick up in the tank. These filters are very high volume and create very little pressure drop. The use of a pre-filter ensures long fuel pump life and can eliminate low flow conditions caused by debris entering the pump inlet.
The final link in the fuel delivery system is the fuel rail. The fuel rail should be consistent with, or larger than, the hose size. The additional capacity of a large-diameter fuel rail helps to dampen the pulsations created by the fuel injectors and ensures even fuel delivery under all conditions.
Fuel Pressure Regulator and Pulse Dampener
The fuel pressure regulator maintains a constant pressure across the fuel injector. The inlet manifold pressure varies with throttle angle, and engine speed. Small throttle angles and high engine speed produce low manifold pressure (high vacuum). While high throttle angles and low rpm give high manifold pressure. In addition to these conditions, low manifold pressure is associated with idle and high manifold pressure is at full throttle. It is the fuel pressure regulators job to keep a constant fuel pressure across the injector(s) regardless of manifold pressure.
Currently, there are several types of fuel pressure regulators in use. Many late model cars use a return-less system where the fuel pressure regulator is mounted in the fuel tank adjacent to the fuel pump (and therefore requires no return line back to the fuel tank). In most naturally aspirated applications these types of systems are adequate. With forced induction or heavily modified engines, an adjustable fuel pressure regulator with manifold vacuum reference must be fitted.
The two common types of fuel pressure regulators used are non-adjustable and adjustable. As the name implies, a non-adjustable regulator is set at a fixed value and is manifold-vacuum referenced (whenever a regulator is said to be vacuum referenced, this means that the inlet manifold vacuum/pressure is ported into the chamber above the regulator diaphragm).
As manifold pressure increases, the pressure in the top chamber of the pressure regulator increases along with it, allowing the regulator to compensate for the increased demand of the fuel delivery system.
Keep in mind that at idle or low throttle openings with high rpm, there is very low manifold pressure (vacuum). This tends to literally draw fuel from the injector. As manifold pressure increases (as the throttle is opened), this vacuum dissipates and it is harder for the fuel to discharge from the injector. The regulator reacts to the differences in manifold pressure to maintain constant fuel pressure across the injector. There is a spring in the vacuum (top) chamber of the fuel pressure regulator. The spring’s pressure on the diaphragm determines the fuel system’s static pressure. The system’s static pressure is the amount of pressure measured with the vacuum hose disconnected or with the engine turned off. The fuel system’s static pressure is higher than the fuel pressure at idle or under high vacuum conditions.
When the engine is running, the engine vacuum acts against the spring and the effect of the vacuum diminishes as the throttle is opened. At idle, there is a high amount of fuel returned to the tank because the vacuum is pulling the diaphragm seat off of the fuel return orifice, reducing fuel pressure. As the throttle is opened, the diaphragm seat starts to close off the orifice, restricting the amount of fuel flow through the return line.
An adjustable regulator allows the static pressure to be raised or lowered via an adjusting screw that acts on the diaphragm spring. On most adjustable regulators, when the screw is turned in pressure raises and when it is turned out pressure is reduced. Although we highly recommend installing a proper fuel delivery system, raising or lowering fuel pressure can compensate for fuel injectors that may not be properly sized for an application.
Most aftermarket fuel pressure regulators (and OE regulators) use a 1:1 ratio of fuel to boost pressure for increasing fuel pressure in applications where forced induction is used. This means that for every psi of boost, fuel pressure is increased one psi. This ensures adequate fuel delivery under boosted conditions.
Many vehicle manufacturers use a pulse dampener to reduce the pulsations in the fuel rail caused by the opening and closing of the injectors (a dampener also reduces the noise of the injectors). In applications where a new fuel system must be installed, a fuel pressure dampener is integral to ensuring consistent fuel flow to the injectors. AEM fuel rails have a provision for a pulse dampener. The dampener assembly part numbers are:
Before the fuel system is assembled in the vehicle inspect for debris and damages. Before the fuel system is checked make sure to have a fire extinguisher near by in case of fire. After the fuel system is installed you must inspect the integrity of the entire system. Begin by purging the lines. To do this, run the fuel pump with the hose that connects to the fuel rail placed in a grounded container. This will eliminate any debris left in hose during its manufacturing process. Inspect the fuel rail for cleanliness before starting the engine. Make sure that the fuel pressure is set correctly for your application. Then, reattach all of the hoses and run the fuel pump by switching the ignition to the “ON” position (DO NOT turn over the engine at this time), and visually inspect all of the connections for fuel seepage or leaks. If any seepage or leaks are present in the system, repair them before proceeding.
Locate the source of the leak and repair it before continuing any work on the car. Be sure that all gaskets and seals are in place and all hardware is tightened to the proper torque specifications. If after doing this you still have a fuel leak, please call us at (310) 484-2322, extension 203.
The fuel rail is the best location, and AEM Fuel Rails include a 1/8th NPT port for installing a fuel pressure pickup or gauge. Our Universal Pressure Regulator also includes an auxiliary port to install a fuel pressure gauge.
Where should I pick up fuel for my wet nitrous system?
A:
Assuming there is adequate fuel delivery (see “When do I need to upgrade my fuel system?”) the easiest and best place to pick up the fuel is from the fuel rail. If an AEM Fuel Rail is used, there is a 1/8th NPT port on the top of the rail for a nitrous pick up or fuel pressure pick up.
Why don't you make fuel delivery components for my car?
A:
In some cases there is simply not enough demand to warrant the R&D and manufacturing cost to develop fuel delivery components for a specific application. In other cases (mostly newer vehicles) the vehicle manufacturer integrates the fuel pressure regulator and fuel filter into the fuel tank, making it cost prohibitive for us design components for that configuration. In the case of the latter, if you elect to create a return-style fuel system our fuel filter and universal adjustable fuel pressure regulator can be used for a custom application.
What are the thread sizes of the AEM Fuel Rail and Fuel Pressure Regulator ports?
A:
The port thread sizes are 9/16x18, or standard –6 AN fittings. We also include a 1/8th NPT port in the front of our universal regulator (part number 25-302) and on the top of our fuel rails for a fuel pressure gauge or gauge pickup.
Can I use Teflon tape on the fuel deliver component fittings?
A:
Using Teflon tape is not recommended as it can cause clogs which can damage your fuel system or engine and void the warranty on your AEM High Volume Fuel Delivery component. We include crush washers with our fittings to eliminate the use of sealing tapes or liquid thread locker.
Will AEM fuel delivery components increase my power?
A:
Although you may attain minimal gains in power by increasing fuel pressure with the adjustable regulator, generally our fuel delivery components will not increase performance by themselves. What our fuel delivery components do is allow users to deliver a higher volume of fuel to the engine, which is necessary on modified engines that require additional fuel to compensate for increased airflow from porting, turbo charging, supercharging, etc.
Great upgrade especially if you are upgrading other fuel components make sure to upgrade your fuel rail also - and with this Aem rail you cant go wrong - better flow and a easy install even for a total novice -
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