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Return-Type Dual Pump PWM Control Built for Naturally Aspirated High-Flow Fuel Demands
The Aeromotive 66166 VaporWorx ReturnX is a return-type pulse width modulation controller engineered for naturally aspirated builds running two brushed fuel pumps. Where forced induction builds rely on a MAP sensor to trigger higher pump output under boost, the 66166 NA variant uses throttle position, RPM, or other non-boost parameters to manage pump speed, making it the correct solution for high-output naturally aspirated engines that need dual pump flow capacity without supercharger or turbocharger pressure references. This controller allows two pumps to operate in a coordinated, demand-responsive manner that reduces heat and electrical load during cruise while providing full dual-pump flow at high RPM and load.
Key Features
- Aeromotive 66166 return-type (ReturnX) PWM controller for dual pump NA applications
- Designed for naturally aspirated high-flow applications, not reliant on MAP boost sensor
- Pulse width modulation matches dual pump output to real-time fuel demand
- Compatible with brushed-type fuel pumps in surge tank or in-tank configurations
- Reduces pump heat, noise, and electrical load at idle and cruise
- Works with return-type fuel systems requiring a fuel return line
- Remote mount design for flexible installation in any chassis
- Ideal for high-displacement, high-revving engines with large injector and pump requirements
Specifications
| Detail | Value |
|---|---|
| Part Number (MPN) | 66166 |
| Brand | Aeromotive |
| Product Line | VaporWorx ReturnX |
| System Type | Return-Type PWM Controller |
| Application | Dual Pump, Naturally Aspirated |
| Induction Type | Naturally Aspirated (NA) |
| Mount Style | Remote Mount |
| Pump Compatibility | Brushed-type fuel pumps |
| Prop 65 | Yes |
| UPC | N/A |
What's Included
- 1 Aeromotive 66166 ReturnX dual pump NA PWM controller
- Wiring harness and installation hardware
About Aeromotive
Aeromotive has been at the forefront of high-performance fuel system engineering since 1994. Based in Lenexa, Kansas, Aeromotive designs and manufactures fuel pumps, regulators, filters, fittings, and complete fuel system solutions for street performance, drag racing, road racing, and extreme high-power builds. The VaporWorx line represents Aeromotive's demand-matched PWM fuel control technology for modern high-horsepower applications.
Related Parts on Our Site
- Aeromotive 66171 VaporWorx ReturnX Triple/Quad Pump SC Controller
- Aeromotive 66138 VaporWorx Dual Pump Returnless Controller
- Aeromotive 66141 VaporWorx Gen 2 CTS-V Returnless Controller
Frequently Asked Questions
What is the Aeromotive 66166?The Aeromotive 66166 is the VaporWorx ReturnX dual pump PWM controller designed for naturally aspirated high-output builds using a return-type fuel system. It uses pulse width modulation to match two brushed pump outputs to real-time fuel demand without requiring a boost pressure MAP sensor, making it the correct choice for NA engines running dual pumps with high injector flow requirements.
What is the difference between the 66166 and the 66171?The 66166 is designed for naturally aspirated (NA) dual pump return-type applications, while the 66171 is for supercharged three or four pump configurations and includes a 2.5-bar MAP sensor for boost reference. Choose the 66166 for high-output NA builds and the 66171 for forced induction builds requiring three or more pumps.
What is a return-type (ReturnX) fuel system?A return-type fuel system includes a fuel pressure regulator mounted near the injectors or fuel rail. Excess fuel that is not consumed is routed back to the fuel tank or surge tank through a dedicated return line. The 66166 ReturnX controller is designed to work with this style of fuel system. Returnless systems (no return line) require the 66138 or similar returnless controllers.
Can the Aeromotive 66166 be used in drag racing applications?Yes. High-output naturally aspirated drag engines that require dual pump flow to feed large-cubic-inch or high-revving combinations are an ideal use case for the 66166. The controller ensures both pumps ramp to maximum output when the throttle is fully open, providing the sustained high flow rate that large-displacement drag engines demand on a full-length run.
Is the Aeromotive 66166 compatible with EFI and carbureted fuel systems?The 66166 can be used with EFI fuel systems running a return-type architecture. For carbureted applications with a return line and fuel pressure regulator at the carburetor, compatibility depends on the pump and regulator setup. Consult Aeromotive's technical resources to confirm suitability for your specific carburetor and fuel pressure requirements.
Does the 66166 include a MAP sensor?No. The 66166 NA variant does not include a MAP sensor because it is designed for naturally aspirated applications where boost pressure is not a control input. Control is derived from other engine parameters. The 66171 supercharged version includes a 2.5-bar MAP sensor for forced induction builds.
What pump brands are compatible with the Aeromotive 66166?The 66166 is compatible with brushed-type fuel pumps from any brand, including Aeromotive, Walbro, DeatschWerks, and other common high-flow in-tank and surge-tank pump manufacturers. Brushless pump designs are not compatible with PWM controllers built for brushed motors.
Can I run three pumps with the 66166?No. The 66166 is a dual pump controller. For triple or quad pump configurations, use the Aeromotive 66171 ReturnX Triple/Quad Pump Supercharged controller, which provides primary and secondary leader-follower PWM outputs sized for three or four pump operation.
Installation Instructions
- Confirm your vehicle uses a return-type fuel system with a return line routed back to the tank or surge tank.
- Mount the 66166 controller remotely in a location with clearance and away from exhaust heat.
- Connect PWM output wires to each of the two fuel pump relay or pump terminals per the included wiring diagram.
- Wire main power feed with appropriately gauged wire and fusing for dual pump current draw.
- Ground the controller to a dedicated chassis ground point.
- Power the system up and verify operation at idle before advancing to full load testing.
- Monitor fuel pressure at idle, cruise, and wide-open throttle to confirm proper pump output staging.
WARNING: This product can expose you to chemicals including lead and phthalates, which are known to the State of California to cause cancer and reproductive harm. For more information go to www.P65Warnings.ca.gov.
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