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Old 01-16-2013, 01:31 PM   #191 (permalink)
christofoo
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Quote:
Originally Posted by serialk11r View Post
t vago, you're forgetting that in order to produce the same amount of power, the manifold pressure needs to be higher.
Yes, this is about throttle loss in particular. 'Pump cycle losses' as t vago discussed will increase or be about the same with DCD but throttle losses will decrease.

Quote:
Originally Posted by t vago View Post
...
Since DCD only cuts out a cylinder once per firing cycle, intake manifold vacuum never gets a chance to significantly lower,
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Not true.

My argument in #185 was elegant and perfect. I can quickly rephrase it and simplify it even further: You only have to believe three principles:
1) DCD results in higher air mass per cylinder per revolution to produce same torque with fewer combustion cylinders. This is a fixed AFR system, where DCD requires more fuel per combustion cylinder per revolution.
2) Higher air mass per cylinder requires higher throttle position. That's how the throttle works, by design. If that correlation isn't there, then just remove your throttle and drive without it.
3) Throttle loss dominates over 'pump cycle loss' (defined between intake and exhaust valves as t vago illustrated). If this were not true then lean-burn would not work. It is exactly the same.


Last edited by christofoo; 01-16-2013 at 04:25 PM.. Reason: typo
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