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Old 03-28-2008, 09:32 AM   #26 (permalink)
trebuchet03
MechE
 
Join Date: Dec 2007
Location: Bay Area
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The Miata - '01 Mazda MX-5 Miata
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Quote:
Originally Posted by tjts1 View Post
Every car I've had thus far got better fuel economy with cold air intake of my own design. Warm air might help fuel vaporize better in extreme cold but it also takes more energy (pumping losses) to breath in that air. If your car has a knock sensor, hot air will cause the computer to retard timing and reduce power hence efficiency.
depends how warm - some cars, the temps need to be pretty hot for this to happen.

And explain just why pumping losses increase?

Finally, on the subject of vaporization.... Not on a fuel injected car - that's what injectors do - regardless of temperature Given that the amount of unburnt fuel that leaves the car is less than 1% - this isn't a big issue
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