Whale tails?

[grape_ape]

Hi everyone, This is my first time on this site. Looks good so far. I'm trying to increase my fuel mileage and was told that a whale tail will help. Does anyone know if thats true?
All opinions please, I'm only getting 3.5-5mpg.

[rooster]

3.5-5mpg? What are you driving and/or pulling?

[mr mopar]

what kind of truck is it,how fast do you drive,how do you drive(take off fast or slow ans easy),is the motor running well(does it need a tune up,run the overhead,check for bad or faulty injectors) these are the things to think about before anding a whale tale if you have a non areo truck then 5 mpg is about the best that you will do. if i only got 5 mpg i would get rid of my truck , my avg is 6.5-6.7 mpg and i think that is about avg.

[TheLittleGuy]

Turbo 3000D. I put one on and it paid for itself in less than a week. From RI to Scranton, PA to Rocky Mount, NC. Grossing 76.5 and getting with the program. I noticed AT LEAST 1 MPG improvement! So, i deadheaded upto richmond, VA, picked up my next load, hit the "J" in ruther glen, VA to top off the tanks. when i left, i set the cruise @ 65, ran across I-64 to STL and arrived @ my destination (Columbia,MO) with a little over a half tank left.
I have an '05 Int'l. 9400 w/ 450 Cummins ISX, 10 spd. Prior to install, my truck averaged 5-5.3MPG. Less if i was heavy and running the hills, mountains, or high elevations.
What i'm saying is this, without ANY change in driving habits, I saw a 1+MPG increase. The increase goes way up if I stay close to the speed limits. Last week i ran just over 3300 miles and put approx. $683 in my pocket in fuel savings!

[TheLittleGuy]

Oh yeah, the part plus install kit runs about $250. But, for me, it paid for itself in less than a week.
I'm not connected to this company in ANY way and i get no kick-backs if you buy it. Just being a brother trucker. tuesday and wednesday of this week, i ran a multi-stop all over ohio. Approx. 435 miles and I did what resembled the speed limit(58-62MPH). I used 50 gallons of diesel......TOTAL! do the math. that's 8.69MPG!!! Prior to install, under similar circumstances, my fuel economy would have been 6-6.2MPG.
They say to give it 15,000-30,000 miles to see an improvement. But, i literally saw results the 1st week! It's been on 3.5 weeks now and each new week is better than the last.
I know it's worked for me. It could be the best $250 you ever spent!