Interesting fuel savings this morning

I was traveling through Nebraska this morning on a very straight and level road and was bucking a head wind. My computer said I was getting 4.5mpg.

I was approaching a slower truck but a car was coming up on my left so I slowed down a little and was maybe 300 feet behind the truck in front of me. I looked down and I was getting 6.5 mpg. I stayed there for maybe 25 miles and no change. I then passed him and as soon as I started half way up his truck my mpg started to go down and once I was in front, 4.5 again.

So I wait until a truck passes me and I catch up about 300 feet behind and bingo, back up to 6.5 again.

That explains why I'm tooling along and I see a truck catch up to me then he stays with me for 100's of miles!!!! My guess is that they are looking for a truck that has the cruise on and matches there truck in the hills.

I'm sure you all know this but nobody has ever mentioned it. I thought it was pretty cool. I'm thinking about putting an anemometer on my truck and doing some experiments. I find this interesting.

Also, a study was just done. During the hot weather it is better to leave your windows open up to 55mph. After that, it is cheaper to run your A/C due to the added wind resistance that leaving your windows open causes above 55mph.

[Uturn2001]

At 100 yards you were not close enough to see any benefits from drafting, which is an unsafe and stupid activity.

I imagine what happened was that the truck in front of you was simply acting as a wind block which cut down on the resistance on your truck. It sounds like you found the sweet spot for this, which will be different depending on specific conditions at that moment.

Much closer and you would have been dealing with the turbulence from the truck in front of you, farther back and the wind would have had a greater effect on you.

[mike3fan]

At 100 yards you were not close enough to see any benefits from drafting, which is an unsafe and stupid activity.

not to mention fun and exciting!

[rank]

Yes I've noticed that too. And when you're passing a van, if you get really close you can get a side draft off his slipstream.

[LOAD IT]

Be careful DRAFTING to save fuel. The following too closely ticket may offset your savings. 300 feet is too close according to DOT.

[Rev.Vassago]

Be careful DRAFTING to save fuel. The following too closely ticket may offset your savings. 300 feet is too close according to DOT.

Steve talked to some US MARSHALLS in Washington who said it was okay.

[yoopr]

I was traveling through Nebraska this morning on a very straight and level road and was bucking a head wind. My computer said I was getting 4.5mpg.

I was approaching a slower truck but a car was coming up on my left so I slowed down a little and was maybe 300 feet behind the truck in front of me. I looked down and I was getting 6.5 mpg. I stayed there for maybe 25 miles and no change. I then passed him and as soon as I started half way up his truck my mpg started to go down and once I was in front, 4.5 again.

So I wait until a truck passes me and I catch up about 300 feet behind and bingo, back up to 6.5 again.

That explains why I'm tooling along and I see a truck catch up to me then he stays with me for 100's of miles!!!! My guess is that they are looking for a truck that has the cruise on and matches there truck in the hills.

I'm sure you all know this but nobody has ever mentioned it. I thought it was pretty cool. I'm thinking about putting an anemometer on my truck and doing some experiments. I find this interesting.

Also, a study was just done. During the hot weather it is better to leave your windows open up to 55mph. After that, it is cheaper to run your A/C due to the added wind resistance that leaving your windows open causes above 55mph.

It's called Drafting

[Jumbo]

I was informed by the DOT when I asked that 300 feet following when empty BUT 1000 feet when you are loaded.

[LOAD IT]

I was informed by the DOT when I asked that 300 feet following when empty BUT 1000 feet when you are loaded.

If Barney Fife says you are closer that 300 yards you will get a ticket 9 times out of 10. Loaded or empty.

Ha, if your 1000 feet on the East Coast that's enough room for 20 semi's and 35 cars to pull in front of you. You'll be at a dead stop in no time flat trying to keep your 1000 foot clearance.

I was cruising along yesterday through Idaho and another truck passed me and once again my computer said my MPG went way up. I kept up within 300 feet which in my opinion was a comfortable distance between us. I think someone was correct before, it's not drafting but the fact that the other truck was making a path through the head wind. There was a steady headwind breeze. I think to draft you need to be right on someones tail.

[person]

You were 300 feet behind and it was still affecting your mpg?

[allan5oh]

It all depends on the wind, sometimes they'll pull in front of you and your MPG will go down.

In the winter, it can be absolutely brutal when someone is passing you. Sometimes it drops 3 mpg.

I don't pay attention to instant, especially when accelerating. It doesn't make sense to. Instant mpg is only usable as a tool for steady state(cruise).

You were 300 feet behind and it was still affecting your mpg?

It sure looked like it by my computer. After a while I backed down to my normal cruising speed and the MPG slowly went down as he pulled away from me. Like I say, my only guess is that he cut the head wind for me. I'm thinking about buying a cheep anemometer (wind speed indicator) and doing some experiments. It would be interesting to know how much a head wind affects you.

[Orangetxguy]

It sure looked like it by my computer. After a while I backed down to my normal cruising speed and the MPG slowly went down as he pulled away from me. Like I say, my only guess is that he cut the head wind for me. I'm thinking about buying a cheep anemometer (wind speed indicator) and doing some experiments. It would be interesting to know how much a head wind affects you.

LOL...My Cat messenger tells me I get 399 mpg, when I'm coasting down a hill. Unfortunately I can't coast all the way from Saint Louis to Houston.

The true Drafters are the "Ninnies" whom pull up to within 40 feet of the trailer and stay there.

[quote="Orangetxguy"]

The true Drafters are the "Ninnies" whom pull up to within 40 feet of the trailer and stay there.

I just keep hitting my cruise control and going 1mph slower until they get fed up with putting on their brakes and pass me.