Quote:
Originally posted by fahrgewehr2
Will a turbo diesel produce some vacuum when the turbo is spinning? It seems like it would?
Also, as fas as I can tell, a gas engine is given air when you put your foot on the gas, and the amount of fuel necessary is then added (metered). With a diesel, your foot sends the engine fuel. Is this (basic) description correct?
And finally, exactly why does a diesel engine produce no vacuum?
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There only would be vacuum between the turbo and the airfilter if the airfilter acted as a throttle (plugged). The air between the turbo and the intake valve is under some amount of pressure boost if the turbo is spinning up.
And finally, a diesel exactly doesn't have intake vacuum because it has NO THROTTLE plate (since 1976 240Ds).
Take a straw, put your finger over the bottom, suck, your have manifold (straw vacuum). Remove the throttle plate (your finger), suck, do you achieve any vacuum? In a gas engine speed is determined by the amount of air. By placing a plate in the stream restricting the flow the engine sucks as in the straw case against your finger. BTW keep your hands away from the intake of a running diesel you might wind up coming out the exhaust, boy can they suck.