Factory BMW E46 M3 fuel pumps will lose fuel pressure over time as they degrade. This can cause a boosted E46 M3 to run lean under boost. We recommend all E46 M3's that are running forced induction or have an aging OEM fuel pump to order and install this Walbro 255 fuel pump kit. After testing several different in-tank fuel pumps, we found the In Tank Walbro 255 pump to outperform all other in tank pumps on the market including the factory pump at fuel pressures over 85psi. The static fuel pressure on the E46 M3 is 73psi and this pressure goes up 1psi for every pound of boost above atmospheric. So for a car like our HPF stage 2.5 running 23psi and nearly 700rwhp, the in-tank fuel pump along with the in-line fuel pump must supply fuel at 96psi to keep the engine from running lean. The OEM in-tank pump + walbro in-line pump on a stage 2.5 has a fuel pressure loss of 8psi at peak torque. This is why the map in the HPF stage 2.5 has the injectors held open longer to compensate for this loss. The better solution is to have the correct fuel pressure and the fuel map to match. This Walbro in-tank pump now comes standard on the stage 2.5 turbo kit, but we recommend this upgrade for all supercharged, and HPF turbocharged customers including the stage 1, 2, 3 and 4. We did not include this upgrade in the HPF stage 1 and 2 kits because it is not as critical as those kits are only running 13psi with a max fuel pressure of 86psi. We do however feel it would be a good upgrade to do especially if the factory fuel pump is old or has a lot of miles on it.
The BMW E46 M3 fuel pump hanger is very ingenious in that the OEM pump simply slips right into the hanger and locks in place. The Walbro 255 in-tank pump is smaller than the OEM pump so we designed a sleeve that the Walbro pump sits in that makes it exactly the same dimensionally as the OEM pump. This ensures the placement of the pickup sock is in the same location along with the electrical connections. It also allows the pump to simply drop right into without any modifications to your existing fuel system and holds it in place securely.
Note: Before you begin the installation make sure you have less than 1/4 tank of gas in your car.
HPF E46 M3 Walbro In Tank Fuel Pump Install Kits from HorsepowerFreaks
hpf e46 m3 walbro in tank fuel pump install kits from horsepowerfreaks fuel pump install kits. Install and installation help available for parts and accessories for these model years.
Zoom 
(6 of 10)