Properly testing full undertray on 2011 Ford Ranger

[freeside]

Folks,
Thanks much for the great feedback. I've been very busy and haven't had time to properly respond although I've read everyone's posts. More soon.
-Stephen

[freeside]

I performed my first A-B-A test last night, as a shakedown on procedure.
Test was on only the first section of the belly pan, from front bumper to just rear of the front A-style control arms, approximately 41" of underbody covered out of 16' something of truck.

Test results were depressing. There was little or no change due to the belly pan.
A: average MPG = 27.9
B: average MPG = 27.5
A: average MPG = 27.25

The only thing that I can see causing the downward trend was dropping temperature and rising humidity, or the number of cars passed on the first test made my MPG higher...
Tests were performed on a 37.4 roundtrip drive starting at 11:29pm and going until almost 2:00am this morning. Temperatures varied from 46 degrees F to 42 (according to online weather data), but observed Intake Air temps averaged 46 degrees F.

See attached data sheet, typed up from hand written.

Any thoughts?
Thanks,
-Stephen

[MetroMPG]

Don't mean to discourage, but I'm not surprised you couldn't tease results from the addition of a 41 inch undertray.

On my Firefly/Metro the complete, bumper to bumper undertray only suggested a 2.2% change (A-B only).

Post #12: http://ecomodder.com/forum/showthrea...9.html#post873

[freeside]

@MetroMPG: Oh, wow. For some reason I had it in my head that a belly pan would show better results on a truck due to it being higher off the ground.

For the level of effort to cover the underside of a truck, I'm wondering if 2-3% is worth it... I guess I was expecting somewhere from 5-15% based on my readings.