Thread: Increased MPG
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Old 09-22-2014, 05:31 PM   #12 (permalink)
Jordo!
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Quote:
Originally Posted by Chuck33079 View Post
True, unless possibly the mods increase the VE of the motor and you get some mpg gains through greater efficiency. We'll never know if the mods or the tune are what increases mpg since so few people are going to spend the coin to tune a bone stock car. Plus it all goes out the window when you put your foot into it anyway.



I dunno about that... turbos and superchargers effectively increase VE, so there may be proportionate improvements in MPG, but the absolute changes in air volume still mean you need more fuel to burn it, meaning the overall MPG isn't going to improve.

Power gets lost as heat and fuel gets "wasted" (at least in terms of producing work) if unburnt. The former doesn't really factor much into MPG in real world conditions relative to the latter.

On that note, for a boosted motor, an intercooler will both condense the charge and also chill it -- meaning more grams of air consumed per sec (i.e., more efficient) and also less fuel needed to cool the charge and prevent autoignition. But... the greater volume of air still needs more fuel to produce power, so MPG is either going to break about even or go down.

I really don't understand how a freer flowing anything will improve MPG -- you may get less pumping losses, but if the AFR is fixed, fuel consumption will change with air mass taken in.

Arguably, if power is lost as heat, it would make just as much if not more sense to say that higher flow means a cooler charge. I'm sure that's true, but the effect is negligible.

Or am I missing something here?
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Last edited by Jordo!; 09-22-2014 at 05:45 PM.
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