Curious as to why BMW chose to regulate pressure at 72psi rather than 43psi? From Shiv's numbers our pumps flow better and have less draw at 43psi. I understand the need for the higher pressure from what Shiv said:
Quote:
Originally Posted by shiv@vishnu
With EFI (Electronic Fuel Injection), fuel system pressure raised to a much higher, standardized and somewhat arbitrary 43psi. This pressure increase was done to improve the injection accuracy and precision. The more pressure behind the fuel injection squirts, the less injector on-time (in milliseconds) is necessary to delivery the necessary fuel mass to the intake port. The higher pressure also improved the atomization characteristics of the fuel. The finer the spray, the better it would swirl with the air in the combustion chamber, creating a burn-friendly homogenous air/fuel charge.
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But how much are these things improved at 72psi vs. 43psi?