Just how far up a bus's butt do I have to go to get a noticable drafting affect that effects my gas milage? I was 1-2 car lengths behind one of those huge tour busses going 70MPH on a section of flat road I drive every day. On this section my meter bar always reads a speck above 25MPG. In this position behind the bus it still read the same. Am I doing something wrong?

 

I'd say about a car length and a half before you see it. You should be able to "feel it" in that when you accelerate a bit quicker. Thats how I can tell I'm drafting.

 

The closer the better.

 

They did a test on this on mythbusters. I forget the results though. But in my opinion if your going to notice any difference its not going to be 25 mpg to 35mpg just being behind a bus. Dont expect 900 miles out of the tank and be able to really tell the affects.

 

I'm not sure you'd notice it much with a school type bus. I did notice a big difference behind a mostly enclosed horse trailer or a tractor/trailer. I'm guessing because they have a pretty low ground clearance in the back and punch a bigger hole.

I could get about 35 MPG @ 65-70 MPH..I kept about 2 or 3 car lengths back. This was behind a convoy of those high end horse trailers.

I'm not sure it's really worth the loss of safety margin, the rocks thrown up, or even the added stress and ticking off the driver in front of you

 

Not to mention the fine and points that come along with the ticket. The hasle of being pulled over wasting gas and such.

 

Mythbusters said it helped a little but it was too dangerous to make it worth it. If they touch the brakes, well.. that wouldn't be a good thing.

 

can you guys tell me what in world are you talking about?

 

Put your car in nuetral and tie a rope from his rear bumper to your front. Youll notice an even higher fuel mileage.

 

Drafting. When you pull real close to the car in front of you that is breaking the wind. So then your car doesn’t have to letting the motor work less to keep you going. More effective in NASCAR where they are going 200mph with very aerodynamic bodies.