Quote:
Originally Posted by darknightohio
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Yes valvetronic is back in BMW engines again, due to technical reasons the engineers weren't able to use valvetronic correctly with the N54 but have finally overcome whatever obstacles were in their way and now it returns to the N55 with direct injection...
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I guess I like the supposed improvements in the N55, but I'm just wondering why Valvetronic needed to be used in light of the following (from the 2007 N54 Engine Mechanical pdf
here, page 8):
Quote:
Valvetronic
The N52KP and N51 retain the already proven Valvetronic system. The only changes to the system for 2007 is an optimized VVT motor.
On the other hand, the N54 engine does NOT use Valvetronic. This is due to the fact that the Valvetronic system is designed to reduce pumping losses. It is a system which improves volumetric efficiency by optimizing the air charge.
A turbocharger system is also designed to increase volumetric efficiency by reducing pumping losses. Therefore, there is no need for both of these systems to be employed on the same engine. The N54 gains maximum efficiency by the use of turbocharging and direct injection.
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