Break in - New Engine Deceleration - under own vacuum or drivetrain brake?
A little background. I do not regularly downshift when I drive. I will usually just throw it in neutral and when I am ready to go again, select a proper gear for the new speed and head off. All I have ever heard during break-in process is not to downshift the engine, let it fall to idle under its own vacuum. So, naturally, being raised that way, that is what I thought. Engine technology, theory, design, and clearances have changed greatly over that past few years. So, instead of just blindly following what I have heard growing up, I did some research. That leads me to where I am now.
The theory behind door #2, downshifting, engine braking, etc, is to remove the ring and cylinder material out of the exhaust instead of letting it collect between the grooves of the rings.
I do not know the reasoning for door #1. What are y'alls thoughts/opinions/theories for letting the engine fall to idle under vacuum or loading?


