Oliver Enterprises

Guys - Maybe you all can help me diagnose this problem. Last week the weather had a cold snap. But this past weekend, and this week so far it has been quite pleasant. So, I've started putting my windows down. I don't put all 4 down, it's just too much wind. And if I only put down the driver's window, I get too much buffeting in my ear. But if I drop both left side windows, it is very pleasant. No buffeting, and just the right amount of wind stirring in the car.

I just got through refueling at lunch. And my mpg was WAY down. Does putting the windows down create THAT much drag? Should I go back to only putting 1 window down? Would that help? Do you think maybe this problem root cause is based on increased drag? Other? Let me know what you guys think could be causing the poor mpg.


On a side note - with the windows down, I can really hear the exhaust / Exhaust Vents. It sounds friggin awesome! I heard a Jag with what I think was a V8, and it sounded great. And I'll be damned if I don't think our V8 sounds even better with the Exhaust Vents! I'm revving (a little) at stops, and accelerating much harder, at like every instance, just so I can hear the exhaust! It sounds so great, it gives me chills to hear it. The car is so close to perfect now.


Jason

213374U

I may have found your problem

dfkd

I do remember that there was test I saw (maybe Mythbusters) where it did turn out that just windows down has a worse effect on gas mileage than the AC being on.

The excellent 0.26 Cd around the body of this car would definitely suffer with windows down and I suspect a LOT of our highway gas mileage is dependent on slipperyness through the air.
The V8 ain't helping...

mckellyb

Yes, having the windows down results in more drag than having them up.

However...I very, very seriously doubt you're going to see an actual difference...super-aerodynamic mass-produced car, or not.

For example, I track every single fuel purchase, mileage, date, and any extenuating circumstances (like letting it idle for 45 minutes because I'm playing with the suspension's settings), and never, EVER have I seen a marked difference in A/C on or off, windows up or down.

Now...oxygenated winter gasoline versus summer gasoline? You bet! Same goes for that ethanol garbage.

But windows? It's so minor, it won't register.

I routinely drive to work with the sunroof open, because it's early and I'll do so down into the 30s, Fahrenheit, and drive home with all the windows down, roof open, on the way home if it's below about 75F. MPG is always about the same, 21.5-21.7.

Occasionally, I'll get lucky with a 22.5 MPG tank, but sometimes you get lucky with the lights & traffic every single day. Then there are other tanks which are 20.3-20.7, because that 4.6L V8 can sing!

sktn77a

iTrader: (2)

Haven't seen any tests on windows-down mpg. But I remember the ones for AC from the 1970s gas shortage. Small car (Pinto/Vega) was about 3-4 mpg while a big car (V8) was only around 1mpg.

I doubt windows-down would produce a measureable difference unless you monitored it carefully over several thousand miles.

Nospinzone

I don't watch NASCAR much, but don't they have their windows open?

comotiger

Sure, and they probably average 1 mile per gallon

SW17LS

You asked a question and then answered it in the next sentence lol

The issue is your more liberal use of throttle with the windows down, not the windows being down

Nospinzone

OK wise guy, very funny!

I was referring to how little drag there might be.

Of course I guess it could be a safety issue if they had to get the driver out fast.

Oliver Enterprises

Yeah ... Ok. Ya got me!

I was really driving around with the windows down, and I couldn't believe how great the exhaust sounds now. What a difference between now and last year, when I was happy with everything but the silence. But now, I've got all the colors of the rainbow. Nice house, picket fence, 2.5 kids, a loving wife (ahem), an LS 460 that sounds badass while not being overly loud and/or sounding like dirt track racecar. Ahhhhhh, life is good.

I'm not really concerned about fuel mileage. But when I put the windows down I was accelerating more briskly so I could hear it, and LOVE the way it sounds at 2,000 rpm. And it hits that frequently when accelerating and it just tingles my senses. And when driving this way I thought, "I bet I see lower mpg if I keep driving like this." And then the thought of making this post came to mind.

Sorry I'm not contributing much lately. My new job is finally getting me busy. PLUS - I RECEIVED A FREE CAR!!!! A 1972 Plymouth (Valiant) Scamp. It is in AWESOME shape. I've had to spend time with it giving it TLC. Drove it around the neighborhood and found that the heater core is leaking. So a "replacing the heater core" project has begun. It is nowhere near as difficult to do on that car as would be the LS. But it is difficult enough as-is.


Jason