Do higher intake temps increase MPG, or decrease them?

 

higher temp. air intake = less density
air with less density will make the engine less efficient, also increasing brake specific fuel consumption.
so yeah less mpg

 

my guess...the differences are neglible...especially with modern ecu's which compensate for varying IAT's.

with that said, cooler denser air makes more power...but requires more fuel to do so.

warmer air makes the system less efficient...but requires less fuel to make less power.

(provided there is a working 02 sensor telling the ecu to keep the air/fuel ratio within a specific range)

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by mmuller &raquo;</TD></TR><TR><TD CLASS="quote">higher temp. air intake = less density
air with less density will make the engine less efficient, also increasing brake specific fuel consumption.
so yeah less mpg</TD></TR></TABLE>

This is moot.


There is no definitive answer as there are many variables. Generally for closed loop operation economy will increase with air temp. The opposing variables are ignition corrections due to the higher temps.

 

I was always under the impression that if you improved overall efficiency you would get better cruising mileage as the motor would make more power and thus require less throttle to maintain a given cruise speed...

 

thats right , with more efficiency you have to load the engine less to get the same power
and ignition timing will not have a mayor effect on mpg


and whats moot?