Deatschwerks DW400 Fuel Pump 94-07 WRX/STI

The DW400 is the highest flowing brushed in-tank pump on the market. But the flowrate of 500LPH at 0psi and 415LPH at 40psi only tells part of the story. Much more important than high-flow at low pressure is a pump’s ability to hold on to that flow under high loads of fuel pressure and boost pressure. The pressure range of 70-100 psi is where modern boosted EFI engines make their peak power and thus need their pumps to perform at their best. Since the DW400 was engineered with this in mind, it was no surprise that it significantly outperformed the benchmarked Walbro 450 “e85”. During side-by-side comparisons, the DW400 did flow 5% more at 40 psi, but more meaningfully, flowed an average of 31% more in the 70-100 psi range.

The development of a 400+ LPH pump in a footprint small enough for in-tank use is a significant engineering feat. To ensure success, we turned to our friends at Bosch Automotive Aftermarket to collaborate on a solution. Our target was simple yet challenging…

1. Outflow all other in-tank brushed pumps on the market
2. Maintain flow under high loads of fuel pressure and boost pressure
3. Withstand fuels of all types including ethanol and race gas

The resulting pump exceeded our high expectations not only for performance, but also for quality. The DW400 exemplifies the high engineering and manufacturing standards of Bosch, GMBH.  Features include: carbon commutators and brushes, fully encapsulated and machine balanced armature, PWM compatible composite turbine impeller, and die cast metal inlet endcap. The DW400 is manufactured in Germany and then delivered to Oklahoma City, OK where DW performs final QA testing, packaging, and distribution.

All this performance is packaged into a 46mm body which will fit into many OE aftermarket pump modules.  The 46mm body is a 16% smaller footprint than the Walbro 450 “e85” 55mm bell bottom.  However, it is also a 7mm diameter increase from a standard 39mm pump.  Therefore, modifications may be needed to fit the pump into OE modules.  The DW400 includes a universal install kit containing a filter, electrical harness, hose, and clamps.

Additional Considerations

1. Wiring – A 400+ LPH pump draws substantial current (16-20 amps at typical operating pressures).  Make sure your chassis wiring is up to the task of delivering this much current.  A DW hardwire kit (part number FPHWK) is an inexpensive insurance policy.
2. Size – The DW400 is a 46mm diameter pump. Standard in-tank pumps are 39mm diameter.  Modifications to the fuel pump module will be necessary on some applications.
3. Universal Fitment – Unlike other DW in-tank pumps, The DW400 is not an application-specific fitment pump.
4. Check-valve – the DW400 does not have in internal check valve.  An in-line check valve may be necessary for easy engine starts in some applications.