And I'm still laughing, because this remains a crock.

Accelerating the same Mass over a shorter period of time = more work = more energy required. Physics 101.

Yer single best indicator of fuel efficiency is Throttle Position - monitor TPS with whatever (Scangauge, Edge, LiveWire, ChitHawk, whatever) and keep it as small as possible for a given rate of travel. And make sure yer TC is Locked. And yer parking brake is off, lol.

Peyote will only alter yer perception, not the facts.


Deek

 

I have the spreadsheet to prove it. I thought the same as you before I tried it. The math does not lie! Now, I'm not talking WOT take offs, but definitely what I would call jack rabbit starts. Just getting up to speed as quickly as is reasonable instead of easing off and taking forever to get up to 60-70 mph. Also, coasting in these trucks helps a lot. And idling is a killer. But, regardless, I drive it like I stole it.

 

The EPA has recently updated its test procedures for estimating fuel mileage. The test now includes 3 additional driving cycles - an aggressive driving cycle; A/C on in hot humid conditions; and a test in cold weather. All these tests are done under very controlled conditions. Estimates for my 2006 4X4 5.4L dropped by an average of 1 mpg using this new procedure and its a little lower than my average mpg. I would like to see the MPG posted for each cycle. Vehicles with smaller engines tend to be more affected - my wifes car estimates dropped 3 mpg. Just for kicks check out some of the hybrid's - toyota prius dropped by 9 mpg. Details of the testing cycles can be found in the link below. You can also use this link to compare your old and new estimates.

http://www.fueleconomy.gov/feg/fe_test_schedules.shtml

 

Well you, apparently, failed physics. Work = force * distance. Accelerating faster to a fixed terminal speed requires increased force, but decreases distance proportionally. The actual work done (in the frictionless world of the physics class) is equivalent to the increase in kinetic energy, which is the same for either case.

In the real world, other losses are very interesting indeed. How efficient is the engine at the loads and speeds experienced. We know there will be increased aerodynamic and rolling resistance losses for the faster acceleration case from the from the higher speeds through the initial part of the run.

You are on to the downside of the slow acceleration here:

The losses for the torque converter are higher for the slower acceleration since the TC remains unlocked much longer, especially at the higher speed (and higher loss portion) of the acceleration curve. My experience at 2K rpm acceleration runs was that it took up to 1/3 mile for the converter to lock. Also, the Otto cycle engine is more efficient at medium rather than low loads (increasing low load efficiency is the attraction of Diesel and direct injection engines.)

So we have different parasitic losses for either scenario. I certainly do not have (nor do I suspect you have) enough data to make a definitive pronouncement about which losses are greater. At a minimum you would need to know the the acceleration curves used (what does jackrabbit mean, exactly,) information on the rolling and aerodynamic losses, the engine efficiency at each speed and load encountered, the torque converter transfer function, and the shift points. Probably a bunch of other stuff as well (driveline losses...)

Calling it a crock outright displays a lack of understanding of the complexity of the problem space.

Lacking the information necessary to perform a theoretical analysis, bluejay at least took data. I would take it over the counter argument at this point.

On th lighter side.... letting off the gas earlier when decelerating, or using a lower terminal speed (as long as the TC gets locked up) will definitely net lower consumption.