Quote:
Originally Posted by G550Mech
I'm new to diesel engines; it would seem to me the greater the load the more boost the engine will require to maintain a certain power output for a given request?
I don't question the fuel rail would be a good means to assess this, but for ease of information, wouldn't boost be an "easier" way to observe the same outcome?
Fuel Rail psi should be an input and boost would be the outcome?
I'm glad I asked this question...
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not necessarily true.
the DME decides what the best way to get optimal load.
Depending on where in the power band, and how much throttle, and many other factors, fueling can be used to create more load, hence why i said at WOT my boost is lower even though i have higher load.
Also note that BMWs LOVE to close the throttle body to prevent traction loss and to maintain a smoothness of the power band.
even with traction control off!
my biggest tuning hic-up was to stop the throttle from closing.
this is also a huge issue with using boost pressure to get any sense of load.
when the throttle body closes, the boost pressure is surged inside the chargepipe, so PSI will be greater, but its not getting into the engine, as the throttle body is partially closed, so it is sort of "ballooning" in the Charge pipe.