Quote:
Originally Posted by Silver-Bolt
Teague,
I need to do more research on the N54 DI fuel system to fully understand how it operates. Typically in boosted application the fuel pressure is constant but the flow varies.
Here is a question I cannot find any information on. What fails in the HPFP? Seals, impeller, etc? Anyone had a bad pump apart to see what is actually failing? Ethonal is extremely hard on fuel systems and especially "rubber" components. I racing applications it takes a completely different fuel system to run alcohol including the fuel pump. Could the U.S. mandated ethonal be contributing to the HPFP failures?
Vintage,
If you happened to get the failed pump from your car you may be able to make your case by having it tested to diagnose what within the pump let go.
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From the engineer dept. BMW N54 uses a Siemens Piezo GDI (gasoline Direct Injection) system. See the following links FYI. Photos and a simplified descrition of the system that even the lawyers can understand - just kidding!! The pump details are interesting 20 Mpa = 2900 psi.
The high-pressure fuel pump is a multi cylinder axial piston pump. The pump is mechanically driven by the engine. It is separated into two parts, the completely sealed oil chamber and the part that contains fuel. The oil and fuel halfs are separated from each other by a membrane. A swash plate transfers its rotation into axial strokes of the pistons, each of which are guided in a cylinder. The oil pressure is transferred from the oil to the fuel via the membrane, the fuel is fed to a common fuel rail, and then to the injectors.
http://www.n54tech.com/forums/showthread.php?t=8774
http://www.ae-plus.com/Key%20topics/...rain-news5.htm