Can having your top down affect your MPG?

Discussion in '1996 - 2004 SN95 Mustang -General/Talk-' started by 04gtdrop, May 18, 2006.

  1. just like the title reads, does anyone know if leaving your top down while you drive affect your MPG?

    Like how much MPG can you or do you lose from your a/c?


    How much MPG can you or do you lose from having your top down?

    thanks SN

    :nice: :SNSign:
  2. Yes, it has to affect your gas milage due to the increased wind resistance, but exactly how much it reduces mpg, I have not tracked.
  3. Mine gets significantly worse gas milage with the top down.... but its worth it! :)
  4. Yes, Car and driver i think it was did a test with two SUV's around a circle track to test gas mileage. Went around until one complete tank was spent to get the average mpg without ac on and windows up. Then ran one truck with windows down and the other one with the windows up and AC on. And it turned out that the SUV with the windows down experienced a bigger loss in MPG. What exactly the numbers were, i don't remember.
  5. I have done this study already. I always reset my trip meter to zero every time I fill up to full and divide my total mileage that I drove within that tank by the amount of gallons that went in.

    My own study shows 15mpg with the top down on most drives, and 17mpg with the top up the whole time on more than 3 consecutive fuel fill-ups. I always calculate my mileage every tank and these are the consistent numbers I usually get.
  6. Mythbusters did a similar test and found the SUV with the windows down had worse gas mileage. You'd probably get better gas mileage with your top up and AC on than with the top down. But hell....we don't drive mustangs to save money on gas! I leave my windows down and AC off just so I can hear my exhaust :D

  7. dang, you are getting some bad gas mileage. i get 17mpg top down and supercharged.
  8. How do you know how many gallons you used exactly? I can see writing down what you filled it up with, but then how do you know you didn't use more or less than what you put in? Unless you run it till its totally empty and dies, then fill it up, and run it until it dies again. No way you'd know exactly how much fuel you used otherwise, which will effect your #'s. Even being off by 1 gallon of gas usage can affect your numbers by 2-3 mpg.
  9. i thought their test was AC vs. windows down...& the SUV with the AC on ran out of gas first?

    But yea...I agree...I don't think about my gas mileage when I drive my car. No fun in that. :nice:
  10. It was windows down and AC on....guess I didn't really explain it well. I was just inferring that if the car had worse mpg with the windows down, it would be even worse with a vert. I could be mistaken, but I thought I was a little surprised by their findings, and I've always thought AC took more gas. But I can't guarantee it.

    I don't even want to know what my mpg is. I made peace with that when I decided to buy this car.
  11. Simple. If you go to the same gas station all the time, this makes it even more accurate. If you fill up till it automatically cuts off (full), then drive till whenever, it doesnt really matter. You could use a half tank or run it till the low fuel light comes on. The next time you fill up, run it up to the automatic shutoff and whala, how many gallons you used is right on the screen at the pump, down to the thousands of a gallon.
  12. ok, cool. Thanks for all the post's guys!

    Gotta love SN!!!!