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[QUOTE=Maestro;174858] So, say your car runs at 1800rpm and 10% throttle at 55mph. If you then go and modify the intake to be less restrictive, you may now need only 8% throttle to maintain this same condition. And the condition that you are maintaining is a certain pressure outside the intake valve. Therefore, in order to maintain the same output you have not changed pumping losses at all, you've simply altered how much restriction is being created by each individual part of the intake. So you are correct in thinking that decreasing intake restrictions would reduce pumping loss at a given throttle position, but what you need to consider is that a reduction in pumping loss on the intake side means more air is now entering the cylinder, and you're producing more power, using more fuel. So to maintain the same RPM/speed/load etc. as before your intake mods, you need to reduce the throttle opening to get back to the same total restriction you had before the mods.
What jumped out at me while reading this is that if it takes less throttle opening to maintain the same speed then your motor is taking in less air and since you have the same air/fuel ratio, you are using less fuel!
Or is there a flaw in my logic?
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