Slight Concern about MPG

[MikeM.]

I too can get better MPG by not using the cruise control.

That shows you have good intuitive throttle modulation. Some people are helpless when it comes to that.

If the instant MPG meter is not lying, it seems that a good WOT operation followed by normal cruising causes better instant MPG readings at normal cruising. This could be explained by better thermal efficiency that is gained after properly heating the engine. If this is true, it may be that babying the throttle too much can actually hurt your MPG
However, getting the best instant reading always involve feather & consistent throttle application, when the engine switches to the Atkinson cycle.

I agree with most of the general principles you described here. But WOT will cause downshifting and running to redline. While I agree that strong acceleration has mpg benefits when done properly, it is never necessary to run it to redline for good mpg's (only for max acceleration). I do think there are MPG benefits from running it up to 4500-5000 rpm's with throttle wide open but it's helpful to use the manual shift to prevent the engine from running all the way to the rev limiter before it shifts. This is best done on long, steep grades otherwise you will be into triple digits before the engine has benefitted from the hard running.

The CX-5 is not like old school cars where the throttle plate angle is directly proportional to the accelerator pedal position. Sometimes the throttle plate will be wide open when the pedal is only depressed halfway. If that's what you mean by "WOT" then I agree. But without additional equipment hooked up it's difficult to know when the throttle plate is wide open and when it is not. Further complicating the definition of "WOT" is the variable valve timing.

 

[CX-5um]

I agree with most of the general principles you described here. But WOT will cause downshifting and running to redline. While I agree that strong acceleration has mpg benefits when done properly, it is never necessary to run it to redline for good mpg's (only for max acceleration). I do think there are MPG benefits from running it up to 4500-5000 rpm's with throttle wide open but it's helpful to use the manual shift to prevent the engine from running all the way to the rev limiter before it shifts. This is best done on long, steep grades otherwise you will be into triple digits before the engine has benefitted from the hard running.

The CX-5 is not like old school cars where the throttle plate angle is directly proportional to the accelerator pedal position. Sometimes the throttle plate will be wide open when the pedal is only depressed halfway. If that's what you mean by "WOT" then I agree. But without additional equipment hooked up it's difficult to know when the throttle plate is wide open and when it is not. Further complicating the definition of "WOT" is the variable valve timing.

I think up-shifting shortly after reaching max torque (3250 rpms for 2.5 and 4000 rpms for 2.0) is the sweet spot in terms of good acceleration yet good mpgs.

 

[erhayes]

Most of my acceleration is accomplished at below 2,500 rpm and I let the vehicle speed come up to that rpm rather than push the vehicle up to the rpm and then back off. That results in at least 3-5 mpg improvement. That is not to say, I don't have some fun by accelerating out on a ramp when the AT shifts or I shift at 4-5,000. Ed

 

[ALafya]

The CX-5 is not like old school cars where the throttle plate angle is directly proportional to the accelerator pedal position. Sometimes the throttle plate will be wide open when the pedal is only depressed halfway. If that's what you mean by "WOT" then I agree. But without additional equipment hooked up it's difficult to know when the throttle plate is wide open and when it is not. Further complicating the definition of "WOT" is the variable valve timing.

I think I did not explain my self well.
Imagine 2 experiments, in the 1st there is a short period of hard acceleration where the pedal is floored, followed by a period of normal highway cruising, where the pedal is pressed lightly only to maintain speed.
The 2nd is where the vehicle is accelerating leisurely to the desired speed, followed by a period of normal highway cruising, same as above.
So, the only difference between experiments is the 1st part. The latter part of both has similar conditions. Now, you'd assume that the instant MPG on the 2nd part of these experiments should be identical. It is an instantaneous reading, so it should not be related to what transpired before. However, it seems to me that in the 1st experiment I get better instant MPG reading while on the latter part (i.e. normal cruising). If this is really true, and not a measurement error, then it is a result of how acceleration was performed earlier, even though it is no longer in effect.

Now, of course, it is a different question what was the overall MPG over entire experiments (i.e. not instantaneous) in both cases, and I would agree that staying off the redline area as well as not too low on the scale would be a good advise, perhaps close to the max torque point, where the engine is most efficient.
However, if you consider a short period of floored pedal compared with an overall long trip, where the pedal is mostly used moderately, it would be of little consequence.