Slipstreaming

Discussion in 'Fuel Economy' started by timw4mail, May 2, 2014.

  1. timw4mail

    timw4mail Well-Known Member

    I know slipstreaming / "drafting" is somewhat frowned a pon, and for some good reasons.

    However, especially with a smaller car, being in the wake of a larger vehicle dramatically reduces drag.

    In windy situations it can make all the difference when trying to cruse at a set speed.

    Please note, I mean at a safe distance, not tailgating.

    Thoughts?
     
    Last edited: May 2, 2014
  2. EdwinTheMagnificent

    EdwinTheMagnificent Legend In His Mind

    When possible ( not often ) I try to "surf" in the wake of a semi-trailer by being in the adjacent lane ( preferably on the truck driver's side ) and about even with the back of the trailer. This way , I can get a nice tug from the trailer that might be an additional 10 MPG and still be safe. There may be an official term for this maneuver ? Don't know.

    But it works.
     
  3. Ophbalance

    Ophbalance Administrator Staff Member

    Edwin: it's in the glossary as a Traffic Side Draft.
     
  4. ALS

    ALS Super Moderator Staff Member

    The down side of drafting other than the inherent safety issue of being too close to the vehicle in front of you is the damage done to the front of your car at speed. Those trailer tires are throwing pretty much everything they roll over up in the air. If you're sitting behind it under say four or five second back that material is going to impact the front of the car.

    I tested the distance back that I could still be in the draft, even at three seconds behind the trailer I was still benefiting. At that distance running 65 mph I could still hear small road debris impacting the windshield.

    My question is, a new windshield, a front end and hood paint job or even an AC condenser worth the .50 a gallon you are saving drafting?
     
  5. brick

    brick Answers to "that guy."

    I'm with Al. I don't drive behind anything for any length of time if I can help it (and I almost always can). I like my life and, frankly, I like my car. Instead I just cruise at the PSL. 99% of the time that means I'm getting "good" fuel economy (as far as my thirsty ride is concerned) while all the rolling road hazards cruise on by.
     
  6. EdwinTheMagnificent

    EdwinTheMagnificent Legend In His Mind

    I thought there was a name for that !

    Thanks, Matthew.
     
  7. SD3_Driver

    SD3_Driver Well-Known Member

    There are some benefits with slipstreaming, but, most of the time are not worth the effort... I have found some in long highway drives with very specific kind of rigs that are going at my speed ( depends on which car I'm driving ) and road and traffic conditions are good enough for me to give it a shot. On short drives, the benefit will be so small that it is not worth the time and effort...
     
  8. worthywads

    worthywads Don't Feel Like Satan, I am to AAA

    Only time I decided it was worth it was driving I-80 from Laramie to Rock Springs Wyoming. With pretty much continuous 45 mph head winds it was better just to tuck behind trucks lumbering along at 55 fighting the same wind.
     
  9. timw4mail

    timw4mail Well-Known Member

    Yeah, I've noticed huge differences in headwinds.
     
  10. some_other_dave

    some_other_dave Well-Known Member

    I've gotten noticeable benefits from following large trucks at a safe distance. The largest benefits were when the truck was going slower than I felt comfortable doing on my own. So I could tuck in behind them, and anyone coming up behind us could see that I was not the person "holding up the line". The truck, after all, is a lot more visible than the MINI. So they'd go around with a lot less fuss, and I could cruise at ~5 MPH lower than my "typical" cruising speed without worries.

    That was good for ~15 MPG if I recall correctly!

    -soD
     
  11. timw4mail

    timw4mail Well-Known Member

    That's also true. The combination of lower speed and lower wind resistance adds up to quite a difference in FE.
     
  12. RedylC94

    RedylC94 Well-Known Member

    Good plan, IF you can find such a truck. In my experience, large trucks steadily doing less than 65 mph or so on Interstates for more than a short distance are pretty rare.
     
  13. some_other_dave

    some_other_dave Well-Known Member

    Yeah, most of the time the trucks are going faster than I want to, so I just let them go...

    -soD
     

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