Interesting Observation
#11
01-22-2008, 07:38 PM
RE: Interesting Observation
my car will be in 5th gear by the time I hit anything above 35.............yes the engine has enough grunt to effortlessly pull the car.
55 mph is only 1.5K on the tach and 70 is 2K MPG on the highway is 31
55 mph is only 1.5K on the tach and 70 is 2K MPG on the highway is 31
#12
01-22-2008, 10:57 PM
RE: Interesting Observation
Lots ofwives tales in this thread, along with good ideas...
Fuel use is based on how much air is taken in by the engine. When you put it in gear (automatic) the tranny's drag causes the rpm to dip which in turn causes the IACV to open a bit to compensate. Even tho it seems to compensate not quite enough in your case, it's still using slightly more fuel in gear. SLIGHTLY. Most (well-adjusted) cars will hold the idle orslightly increase it when the auto tranny is in gear.
If you don't need to impress that Integra over there, you can shift early, keeping the revs under 2500. If you find you just can't resist, you can downshift back down & use your gas when 'necessary'.
Imagine 2 cases... One where you accelerate with very little gas pedal & shift at 3000 rpm. Other case you use much more gas pedal but shiftearly enough, resulting in THE SAME ACCELERATION. Most modern engines will use less gas in the 2nd case.
Here again, fuel use depends on how much air is taken in by the engine. High rpm & closed throttle can be exactly the same air as low rpm & more open throttle. Thermodynamics favors the 2nd case, because the pressure drop across the throttle really sucks down the thermalefficiency of an Otto cycle.
Fuel use is based on how much air is taken in by the engine. When you put it in gear (automatic) the tranny's drag causes the rpm to dip which in turn causes the IACV to open a bit to compensate. Even tho it seems to compensate not quite enough in your case, it's still using slightly more fuel in gear. SLIGHTLY. Most (well-adjusted) cars will hold the idle orslightly increase it when the auto tranny is in gear.
If you don't need to impress that Integra over there, you can shift early, keeping the revs under 2500. If you find you just can't resist, you can downshift back down & use your gas when 'necessary'.
Imagine 2 cases... One where you accelerate with very little gas pedal & shift at 3000 rpm. Other case you use much more gas pedal but shiftearly enough, resulting in THE SAME ACCELERATION. Most modern engines will use less gas in the 2nd case.
Here again, fuel use depends on how much air is taken in by the engine. High rpm & closed throttle can be exactly the same air as low rpm & more open throttle. Thermodynamics favors the 2nd case, because the pressure drop across the throttle really sucks down the thermalefficiency of an Otto cycle.
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