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      04-13-2011, 11:46 AM   #84
BoostedE90
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Drives: e90 335i 6MT
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Quote:
Originally Posted by RobBeck View Post
You guys are failing to see he is talking about standard fuel injection in that passage, not direct injection as we have which incorporates a HPFP.

Those standard systems just have one fuel pump (alas the "LPFP" in our cars). It moves fuel STRAIGHT to the injectors at ~43psi.

We have a LPFP that pushes fuel at 72psi into a HPFP which exponentializes it into up to around ~4000psi to be delivered to the injectors that need this much pressure to overcome cylinder pressures as the N54 squirts fuel directly into the combustion chamber via directly injected injectors. The 43psi systems just squirt fuel into the intake path right before the intake valve where this is no pressure (unless it's FI and then pressure needs to be raised 1:1 but that's another topic altogether).
^^thanks for clarifying. So I take it all DI engines would use a higher psi?

Last edited by BoostedE90; 04-13-2011 at 11:51 AM..
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