Quote:
Originally Posted by t vago
Well, keep in mind that the right-most part of your line would never go below P(man).
The blue line represents would would happen, for a throttle that was just cracked (for instance, if part-throttle engine operation were attempted with too large a throttle body):
See how the blue line quickly drops from P(man) and drops almost to the bottom of the graph. This is because the piston is sucking in more air than the throttle can provide. As the piston slows down and goes to bottom dead center, the cracked throttle is able to provide enough air to lessen the vacuum. |
Thanks for the pretty picture
Valve timing would affect the effectiveness of this as well, of course.
If only we could move to continuous profile camshafts...they are mighty expensive to machine so I hear, but they give low friction high rpm operation, and even less pumping loss than Valvetronic/Valvematic/etc. at part load. Ferrari has them but has them set up more for optimal torque across the rev range, and I hear they have reliability issues due to wear.