AEM E85 Fuel Pump: Your Essential Upgrade for High-Performance, Flex-Fuel Dominance

Investing in a dedicated AEM E85 fuel pump is not an optional upgrade for serious high-performance or flex-fuel applications – it’s a fundamental necessity for ensuring adequate fuel flow, maintaining engine reliability, and unlocking the full power potential of E85 fuel. While standard gasoline fuel pumps might cope with mild ethanol blends or very low power levels, pushing the limits with pure E85 or significant horsepower increases demands the specific capabilities engineered into AEM E85 fuel pumps. These pumps address the unique chemical and volumetric requirements of high-ethanol-content fuels, providing the robust flow, pressure consistency, and material compatibility essential for safe and powerful operation. Choosing the correct AEM pump, installing it meticulously, and understanding its role within a complete E85 fuel system upgrade is critical for achieving your performance goals without compromise or risk of component failure.

Conventional gasoline fuel pumps, even some high-performance variants designed solely for gasoline, face significant challenges when subjected to high concentrations of ethanol like E85. These challenges directly impact performance, safety, and engine longevity. Ethanol possesses different solvent properties compared to gasoline, capable of degrading certain elastomers and plastics commonly found in standard fuel system components over time. This degradation can lead to leaks, contamination, and ultimately pump failure. Ethanol also contains less chemical energy per gallon than gasoline. To achieve the same power output (or significantly more, which is the goal), an engine requires a substantially larger volume of E85 fuel compared to gasoline. This translates directly to a requirement for higher fuel flow rates. Many standard pumps simply lack the flow capacity to meet this increased demand, especially under high-load, high-RPM conditions where fuel needs peak. Inaccurate flow readings or pump cavitation caused by the pump’s inability to keep up results in lean air/fuel ratios – a primary cause of engine-damaging detonation and catastrophic piston failure. Proper pressure regulation is also crucial. Fluctuating fuel pressure caused by an inadequate pump leads to unpredictable fueling, making tuning difficult and risking inconsistent engine performance and potential damage.

AEM engineers its E85 series fuel pumps from the ground up to solve the specific problems posed by E85 and high-horsepower applications. They are engineered for dominance where standard pumps fall short. Material compatibility is paramount. AEM utilizes specialized ethanol-compatible components throughout the pump assembly. This includes seals, diaphragms (where applicable), wiring insulators, and internal components specifically formulated or selected to resist swelling, hardening, cracking, or chemical breakdown caused by prolonged exposure to high-concentration ethanol. This focus ensures long-term reliability and prevents internal leaks that would starve the engine of critical fuel pressure. Delivering the necessary high flow volume is core to AEM E85 pumps. Engineered for high volume output, these pumps are designed to move the significantly larger quantities of E85 required per unit of time compared to gasoline at equivalent power levels. This consistent, high-volume flow is fundamental for maintaining safe air/fuel ratios under peak load and RPM, enabling reliable high-horsepower operation without the risk of dangerous lean conditions. Maintaining robust and consistent fuel pressure is equally critical. Strong pressure output ensures the fuel injectors receive the supply they need to operate effectively across the entire engine operating range. Stable pressure prevents the lean spikes and tuning inconsistencies inherent with undersized or failing pumps. Modern high-performance engines, especially forced-induction variants, demand consistent fuel pressure for proper function. AEM E85 pumps are specifically calibrated to meet the rigorous demands of high-horsepower engines running on E85 fuel. For users needing exceptional flow capabilities, AEM offers brushless E85 pump options. Brushless motor technology provides inherent advantages: significantly reduced electrical current draw (putting less strain on the vehicle's charging system and wiring), higher potential flow rates and pressure capabilities compared to traditional brushed motors, cooler operating temperatures, and potentially longer service life due to the absence of brush wear. Leading AEM E85 pumps often integrate features beyond the pump core itself. Built-in or compatible integrated fuel level senders replace factory units, ensuring your gauge remains accurate. Sophisticated baffling designs combat fuel starvation during hard cornering, acceleration, or braking by keeping the pump pickup submerged in fuel. Multiple inlet ports offer flexibility for complex fuel system setups like multiple pump configurations or surge tank feeds. Many units feature large-diameter inlet feet with robust filtration socks to maximize flow intake while protecting the pump from debris, which is crucial given the increased fuel volume processed.

Selecting the ideal AEM E85 fuel pump is a critical decision directly impacting your engine's performance and safety. Matching the pump to your engine's demands is non-negotiable. Horsepower is the primary determining factor. AEM typically provides specific flow rate ratings (measured in liters per hour - LPH or gallons per hour - GPH) correlated with horsepower support levels for both gasoline and E85. Choose a pump rated above your engine's maximum anticipated horsepower, especially when running E85, due to its lower energy density. Consider future power goals upfront to avoid requiring another pump upgrade shortly after installation. Forced induction (turbochargers, superchargers) drastically increases fuel requirements over naturally aspirated engines. Ensure the pump has ample headroom for the increased demand. Pressure requirements matter. While many fuel injection systems operate around 43.5 psi (3 bar) base pressure, forced induction applications, especially high-boost setups, require significantly higher base pressures (potentially 60 psi, 70 psi, or more) to overcome boost pressure in the intake manifold. Verify the chosen pump can sustain its rated flow at your required operating pressure. Electrical compatibility is essential. Check the pump’s operating voltage range and current draw (Amps). Brushless pumps offer superior flow/pressure capabilities with lower current draw, simplifying wiring demands. Ensure your vehicle's electrical system can handle the pump's requirements; upgrading wiring or relays is often necessary. Physical fitment must be planned. AEM offers in-tank retrofit pumps designed to replace common OEM units (like Walbro styles), drop-in modules for specific vehicle models (e.g., Mustang, Camaro, Supra kits), and universal inline pumps requiring custom installation. Match the pump or kit type to your vehicle's fuel tank configuration and your installation preferences. Research specific part numbers like the popular AEM 50-1200 (340LPH brushless), AEM 50-1000 (340LPH brushed), AEM 50-1205 (Brushless with integrated controller), or dedicated drop-in kits (e.g., 50-1005 for GM, 50-1035 for Ford), ensuring they meet the criteria above for your project. Consulting application guides or knowledgeable vendors prevents critical mismatches.

Installing an AEM E85 fuel pump correctly is as important as selecting the right one. Safety must be absolute priority. Always disconnect the vehicle's negative battery terminal before starting any fuel system work. Relieve fuel system pressure before disconnecting any lines by following the specific procedure for your vehicle (e.g., pulling the fuel pump fuse/relay and running the engine until it stalls). Perform all work in a well-ventilated area away from sparks, flames, or intense heat. Have a Class B fire extinguisher immediately accessible. Meticulous cleanliness prevents contamination. Thoroughly clean the work area around the fuel tank opening. Wear nitrile gloves to avoid introducing dirt or skin oils into the fuel tank. Cap any open fuel lines immediately upon disconnection. Carefully remove the fuel tank access panel or lower the tank as required per your vehicle's service manual. Pay close attention to wiring connectors and fuel line connections to avoid damage. Removing the old pump assembly often requires disconnecting electrical connections, fuel lines, and potentially unscrewing a large lock ring securing the assembly to the tank. Exercise caution to avoid spilling fuel or damaging the tank's sender unit or other components. Preparation of the new assembly is key. If the AEM pump requires assembly into a basket or hanger, follow the instructions precisely. Ensure all seals are properly lubricated with a compatible lubricant (like petroleum jelly or dedicated fuel lube) to prevent tearing and ensure sealing. Double-check that all wiring connections within the assembly (pump to hanger wiring) are secure and correctly routed away from moving parts or sharp edges. Place the new pump assembly carefully into the tank, ensuring it sits correctly and orientation is correct according to the vehicle and pump instructions. Reconnect the electrical connector(s). Reconnect the fuel supply line using new O-rings or seals as specified. Use the correct line disconnect tool if applicable to avoid damaging the quick-connect fitting. Tighten the tank lock ring (if applicable) securely to the manufacturer's specification to prevent leaks. If using an inline pump, mount it securely below the level of the tank fuel, ensuring it's protected from heat, debris, and vibration. Route new high-quality fuel hose (SAE J30R9 rated for continuous ethanol exposure) away from moving parts and exhaust heat. Use appropriate clamps (fuel injection hose clamps, not worm-gear). Wire meticulously using sufficient gauge wire and dedicated relays. AEM E85 pumps, especially high-flow brushed motors, draw significant current. Underestimating electrical demands is a leading cause of premature pump failure or performance issues. Use high-quality wiring rated for the pump's maximum current draw plus a safety margin. Refer to automotive wire gauge charts – 10 or 12-gauge wire is often required for pumps drawing over 15-20 amps. Minimize voltage drop, the enemy of fuel pump performance. Run a dedicated, fused power wire directly from the battery positive terminal to a high-quality automotive relay mounted near the pump (preferably in the trunk or under the seat for in-tank units). Run a dedicated ground wire from the pump assembly to a clean, bare metal chassis ground point near the pump. Factory ground paths are often insufficient. Control the pump via a high-quality relay. Use the vehicle's original fuel pump trigger (or aftermarket ECU signal) to activate the relay coil. This allows the relay to handle the high current while protecting the vehicle's original wiring. Always include an appropriately rated fuse (as per AEM's specifications and your wiring gauge) within 18 inches of the battery positive connection on the dedicated power wire. This protects against catastrophic short circuits. Use waterproof connectors at the tank connection for ultimate reliability. Before reassembling everything, perform a crucial temporary test cycle. Reconnect the battery negative terminal. Turn the ignition key to the "ON" position (don't start the engine) for a few seconds. Listen carefully at the tank opening for the pump to prime. Visually inspect all connections, especially under the car for inline setups, for any immediate signs of leaks. Address any leaks or the pump failing to run before completing reassembly. After successful testing and ensuring no leaks, carefully reassemble the interior trim or secure the fuel tank. Add sufficient E85 fuel (at least several gallons) to the tank immediately to prevent the pump from running dry. Start the engine and monitor for any leaks again, both at the tank access point and along the fuel lines. Check fuel pressure with a gauge if possible to verify the pump is delivering expected pressure. Be patient for initial startup; filling new lines and clearing air from the system may take a few extra seconds of cranking. Immediately check for leaks.

While AEM E85 pumps are engineered for robustness, proper usage requires some specific considerations, and occasionally troubleshooting is needed. Understanding the startup sequence helps alleviate initial concerns. After installation or prolonged inactivity, the fuel lines and rails are empty. Priming cycles (key ON before cranking) help, but be prepared for the engine to crank for noticeably longer than usual (potentially 5-10 seconds) the first time before it fires. This is usually just the pump filling the lines and rails and the injectors purging air. Subsequent starts should be normal. Protect your investment from fuel starvation. Running any fuel pump dry, even briefly, causes intense heat and damage to its internal components, leading to premature failure. Never allow the pump to run without adequate fuel submergence. Maintain at least 1/4 tank of fuel during hard driving maneuvers like track events or spirited cornering to ensure the pump pickup stays submerged. Using the correct fuel filter is critical. E85 can dislodge debris in older tanks or fuel systems. Use a high-flow, quality fuel filter specifically rated for ethanol (look for SAE J30R9 or equivalent specifications) installed between the pump and the fuel rail. A clogged filter is a common cause of low fuel pressure symptoms. Troubleshooting common issues requires systematic checks. If the pump doesn't run at all: Verify battery connection, check the main fuse and relay fuse, confirm power at the relay's input terminal (battery voltage with the key OFF), verify ground connection (check voltage drop or resistance if possible), confirm the trigger signal is reaching the relay control terminals when the key is turned ON. Check any inertia safety switches that may have tripped. Check in-tank wiring connections. If fuel pressure is low or inconsistent: Suspect clogged pre-pump filter sock, clogged main fuel filter, incorrect or failed fuel pressure regulator, excessive voltage drop to the pump (measure voltage at pump terminals during operation – should be within 0.5V of battery voltage), kinked fuel line, exhausted pump (requires replacement). Listen for unusual pump noises (whining, grinding) indicating potential failure. Consult your tuner immediately if experiencing persistent lean conditions, as pump flow may be insufficient for the power level. For brushless pumps requiring external controllers, ensure the controller is powered and properly signaled per AEM's instructions.

Installing an AEM E85 fuel pump is a pivotal step, but it's usually part of a comprehensive system upgrade to fully leverage E85's potential. Injectors with higher flow capacity are mandatory partners for the increased fuel volume delivered by the pump. Stock injectors will be overwhelmed. Tuning for E85 is complex. The ECU must be reprogrammed (via professional dyno tuning) to adjust injector pulse widths significantly, ignition timing advance, cold start enrichment, and potentially other parameters like fuel temperature compensation for ethanol's unique properties. Attempting to run E85 without a dedicated tune calibrated for the specific pump and injectors is extremely dangerous and will likely cause engine damage. High-pressure fuel lines and fittings ensure system integrity. Replace aging soft fuel lines with ethanol-compatible, high-pressure fuel injection hose (SAE J30R9). Upgrade metal fuel lines (e.g., PTFE-lined stainless steel braided) for extremely high-pressure applications. Use AN fittings for secure, leak-free connections. Surge tanks or elaborate multi-pump systems become necessary for extreme power levels (often well over 800-1000+ wheel horsepower) or dedicated track vehicles experiencing sustained lateral G-forces where tank baffling may still allow brief fuel slosh uncovering the pickup. Regular fuel system maintenance preserves performance and reliability. Replace the main inline fuel filter at least annually or as dictated by your tuner or driving conditions. Inspect the pump for unusual noise periodically. Listen for changes in priming or operating sound. Periodically check fuel pressure, especially if experiencing performance issues. Use quality E85 from reputable, high-volume stations to minimize contamination risk.

Attempting to utilize E85 fuel in high-performance applications without purpose-built components like the AEM E85 fuel pump is a gamble with your engine's reliability and your safety. Standard pumps cannot reliably meet the drastically increased flow demands and lack the material resilience required for long-term E85 exposure. AEM E85 fuel pumps are engineered solutions addressing these challenges directly through specialized ethanol-compatible materials, high-volume flow capabilities, robust pressure output, and reliable construction. Careful selection based on horsepower targets, forced induction status, pressure needs, and vehicle fitment ensures the chosen pump matches the application. Equally critical is professional-level installation emphasizing safety, cleanliness, meticulous wiring practices, and thorough post-installation checks. Integrating the pump with appropriately sized injectors, a dedicated E85 tune, and upgraded fuel system components completes a robust solution ready to handle ethanol's power potential. For enthusiasts pushing the boundaries, the AEM E85 fuel pump provides the indispensable fuel delivery foundation required for consistent, reliable, and high-horsepower performance. Ignoring this critical upgrade jeopardizes your investment and invites preventable engine failure.