Haha, man I must've been tired when I posted, I totally missed that.

 

it's alright bro.

 

wind is a huge factor too...i regularly get 1-3 mpg better going home from school then i do going to school i think the winds go south down the susqhuehanna or something haha

 

Yep, they do. I am not going to measure the wind before each test, but I will try not to do them during a tornado. If they seem too skewed, I will re run them.

 

Has anybody ever tested under-drive pulleys. I have tested my 99 3.9 2wd both before and after. Mind you there may be other factors such as weather and road conditions. I did use my odometer and gas receipt to manually calculate the results. I went from 18.3 mpg to 19.5 mpg. Has anybody else seen these increases in mileage with under-drive pulleys.

 

I've heard they do make a difference. They free up power which always results in higher mpg. So it makes perfect sense.

 

Doesn't seem entirely impossible, so yeah.

 

I ran the 3 speed tests today. All three went phenomenally.

65mph: A:23.7 B:23.3 Avg: 23.50
75mph: A:19.7 B:19.1 Avg: 19.40
55mph: A:28.6 B:27.5 Avg: 28.05

The 55mph had a little inconstancy because of a guy cutting me off on the B run. I didn't have time to redo it.


Test went as follows: Accelerate up to speed, set cruise at X speed, clear overhead computer, run till exit I was using to turn around one , record MPG (while still on cruise). The road was kind of hilly, but I ran A going west on the road, and B going east. Gasoline was Route 66's 100% gasoline 87 octane. Truck was loaded with 2 people, total weight 385, along with 50 pounds of cargo. Truck bed cover was on, clutch fan was off. Ambient air temperature was 56 degrees. The front tires had 35 PSI of air, filled before the drive.

* I think I have covered everything? Like I have said earlier in this thread, I am NOT saying that the overhead computer is 100% accurate for actual MPG. But, it does show a pretty noticeable difference at speed.

I am going on a 6 hour trip this weekend, I am going to run 65 the whole time and see if I get somewhere near what this test shows.

 

So how far did you drive for these tests?

 

Around 7.5 miles, so 15 for each test. My tires are OEM size, and a little worn, so the numbers may be off a little bit, but like I said...I'm measuring the differences, not the actual numbers.