Fuel pump questions almost always arrive too late. The turbo is on, the tune is booked, and someone finally checks whether the pump that came out of a 1990s sedan can feed 400 horsepower on E85. It cannot, and the tuner is the one who has to break the news.
The short answer
- For most street builds on pump fuel, a drop in in tank pump like the DW200, rated by DeatschWerks at 500HP, covers the job with headroom.
- Size up when you go E85, run big boost, or plan to. Ethanol needs a lot more volume than petrol for the same power.
- The common mistake is buying flow and ignoring the wiring. A big pump on tired factory wiring drops voltage, and a pump that loses voltage loses flow.
- Buy the hanger, the filter and the fitting kit with the pump. That is where most installs stall.
How pumps are rated and what the numbers mean
Pump flow is quoted in litres per hour, and that number is only true at a stated pressure and voltage. Push fuel pressure up, which is exactly what happens when boost rises and the regulator follows it, and flow drops. Drop supply voltage, and flow drops again.
That is why a pump listed at 255LPH or 340LPH does not translate neatly into a horsepower number. The honest way to size is to work backwards from injector flow at the power you want, on the fuel you want, at the pressure the engine will actually see, then leave a margin.
Ethanol changes the sums. E85 needs meaningfully more volume than petrol for the same power, so a pump that was comfortable at 400 horsepower on 98 gets tight on E85 at the same output. If flex fuel is anywhere in the plan, buy for E85 now.
Then there is the tank itself. A pump can only move fuel it can reach, and a factory pickup in a half empty tank will uncover under lateral load. That is a surge tank problem, not a pump problem, and no amount of extra flow fixes it.
Picking the right pump for your build
Street builds, factory tank, pump fuel
Start with a direct fit in tank pump. The DeatschWerks DW200 range covers early and late Nissan, Subaru and the Evo, plus a universal version, and DeatschWerks rate the DW200 at 500HP. The DW300 sits above it in the same vehicle specific fitments.
More power, or E85 on the horizon
The AEM in tank pumps include a 340LPH universal fit pump, a 340LPH E85 compatible pump with an offset inlet, and a compact 340LPH E85 design for tight hangers. The Walbro TIA450-2 is a universal E85 in tank option, and the DW400 steps up again where a single pump still has to do everything.
Big single turbo territory
Once one in tank pump runs out, you either add another or go external. AEM list a 400lph external pump and an E85 compatible 400LPH external with an M18 by 1.5P fitting. The Bosch 200 external is the quiet achiever here, and the Walbro 255LPH external arrives with its fitting kit, which saves a trip.
Race, drag and brushless
Aeromotive covers the top end with the A1000, the Eliminator and belt and hex drive pumps for engines that never see a street. On the brushless side, the Injector Dynamics FPS1100 pairs a 1,100lph in tank pump with the BPC100 controller.
| If you want | Go for | Why |
|---|---|---|
| A quiet drop in upgrade on pump fuel | DW200 in tank, your vehicle fitment | Rated at 500HP, fits the factory hanger |
| Room to move on E85 | AEM 340LPH E85 pump or Walbro TIA450-2 | Built for ethanol, still an in tank install |
| A single pump for a big turbo build | DW400 or an AEM 400lph external | Flow for serious power, plan the wiring |
| Consistent pressure at the track | Radium surge tank plus a lift pump | Keeps fuel on the pump through corners |
| Full race flow with control | Injector Dynamics FPS1100 with BPC100 | 1,100lph in tank with a brushless controller |
What to buy with it
The hanger is not optional on most of these installs. Our Radium fuel pump hangers cover the Evo 7 to 9, early and late Subaru, R32 GTR, FD RX7, BRZ and GT86, the Chaser family and the R35. Pumps are sold separately on most of them, which is deliberate: it lets you pick the pump that suits the power target.
Filtration is next. AEM list a high flow filter rated to support up to 500HP and a 7 micron inline filter with -10 fittings, plus strainers that suit their external pumps. Fit the filter the right way round and put it somewhere you can service it.
If the car corners or launches hard, look at a Radium surge tank. The range runs from a single pump tank through to multi pump FCST-X setups, and one version comes with an integrated regulator, which tidies up the plumbing on a tight engine bay.
Last, wiring. Run a proper feed and earth for a big pump and use a relay. A fuel pump controller is worth it on high flow setups, since it lets the pump idle down at cruise instead of shoving fuel back to the tank all day.
Where NZ Performance fits
We stock DeatschWerks, Walbro and AEM pumps in New Zealand alongside the hangers, filters and surge tanks to install them, and the fuel pump hub page lists the range by brand. Hanger fitments live on the fuel pump hangers page.
Pump choice and regulator choice are the same conversation, so read our fuel pressure regulator guide next, and the wideband gauge guide if you want to see the pump running out before it hurts something. For the whole picture, choosing turbo size and fuel system puts the numbers together. Everything ships from Palmerston North.
FAQ
How do I know if my stock fuel pump has run out?
Watch fuel pressure against boost on a full load run. If pressure drops away at the top of the run while the injector duty climbs, the pump is out of puff. A wideband going lean up high tells the same story from the other direction.
Will one pump cover E85?
Only if it is built for it. Ethanol needs a lot more volume than petrol for the same power, and it is harder on pump internals, so buy a pump listed as E85 compatible. Several AEM and Walbro pumps in our range are, and the DeatschWerks in tank pumps are a common E85 choice.
In tank or external pump?
In tank first, every time. It is quieter, it stays cool because fuel surrounds it, and it does not need a feed line pressurising it. External pumps make sense once flow gets past what a single in tank pump can do, or when a surge tank is already in the plan.
Do I need a surge tank?
If the car sees track work, corners hard or runs low on fuel regularly, yes. A stock tank lets fuel slosh away from the pickup and the pump gulps air. A surge tank keeps a small reserve sitting on the pump so pressure holds through a corner.
Why would I need a fuel pump controller?
Two reasons. A controller lets a big pump run slower at cruise so it stays cool and quiet, then ramps to full flow under load. Brushless pumps need one to work at all, like the Injector Dynamics BPC100 that runs their brushless setup.
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