Fuel Pumps & Regulators
Can the stock pump deliver enough fuel when the engine needs to make more power? In this category we bring together fuel pumps, pressure regulators, pump modules, mounting kits and pre-filters for you who are upgrading the fuel system in a project, from a street car running more boost to an engine on E85.
What the pump, regulator and module do
The fuel pump must deliver enough flow at the pressure the engine requires, even at full load. The pressure regulator keeps the pressure stable across the injectors, and on boosted engines it can typically raise fuel pressure in step with boost pressure. You will find fuel pumps both for in-tank mounting and as external in-line pumps, e.g. from Aeromotive, which also offers belt-driven pumps. A pump module combines the pump and hanger in one unit, while mounting kits can make it possible to fit a different pump in the existing hanger.
How to choose a fuel pump and regulator
- Flow at your pressure: A pump's flow typically drops as pressure rises, so compare the flow at your operating pressure, not just the maximum rating.
- Power target and fuel: E85 typically requires more flow than petrol, and the pump must be designed for the fuel you run.
- Placement: In-tank pumps are cooled by the fuel, while external pumps give freedom in placement but require a good feed from the tank.
- Control: Variable-speed pumps can reduce fuel heating at low load.
- Regulator: Choose based on whether the system is returnless or return-style, and whether the engine is boosted.
Brands in this category include Walbro, DeatschWerks, Fuelab and Industrial Injection.
Installation and maintenance
Wiring, relay and fuse must be able to handle the pump's current draw, otherwise voltage drop can result in lower flow. Hoses and fittings must be rated for the fuel you use. The pre-filter on the pump inlet protects against debris from the tank, and a clogged pre-filter can cause pressure drop under high load, so it makes sense to replace it together with the pump. Check the fuel pressure with a gauge after installation, and have the engine management tuned if flow or pressure changes.
Frequently asked questions
Should I choose an in-tank or external fuel pump?
In-tank pumps are cooled by the fuel and can often be fitted in the stock hanger with a mounting kit. External pumps give freedom in placement but require a good feed from the tank. The choice depends on the car, available space and power target.
Does the pressure regulator need replacing along with the pump?
Not always. It depends on whether the system is returnless or return-style, and whether the stock regulator can keep the pressure stable at the new flow and boost pressure. Measure the pressure under load to assess it.
What are typical signs that the pump can't keep up?
Fuel pressure can drop at full load and high RPM, and the engine can run lean or lose power. The cause can also be voltage drop or a clogged pre-filter, so check those first.
Can all fuel pumps be used with E85?
No. The pump, hoses and seals must be rated for E85, and because E85 typically requires more flow than petrol, the pump must be sized accordingly. Check the specification for the specific part number.
