FallingDuck 0 #1 May 16, 2007 Dose anybody know, not guessing, if adding a bug/rock guard to the hood of a Jeep Wrangler improves the mileage? I have had several friends say yes and no, if there are any mechanics or gearheads out there this would be much appreciated. I am most curious about 50+ mph. Thanks. Quote Share this post Link to post Share on other sites
Beerlight 0 #2 May 16, 2007 hmmm.... not sure. I googled "laminar flow" and bug deflector....... http://www.freepatentsonline.com/20040026954.html Quote Share this post Link to post Share on other sites
quade 4 #3 May 16, 2007 It absolutely will NOT improve your gas milage. Anything that "deflects air" causes drag. More drag, means worse gas milage.quade - The World's Most Boring Skydiver Quote Share this post Link to post Share on other sites
PikzeeVikzen 0 #4 May 16, 2007 I've never done that myself but in theory it does reduce drag. A friend of mine added one (just called him) and he says it did improve his but only slightly. He's still happy with the purchase. I'm the twist that turns your key.... Quote Share this post Link to post Share on other sites
Beerlight 0 #5 May 16, 2007 send it to "Myth Busters"....... Quote Share this post Link to post Share on other sites
MrFreefall383 0 #6 May 17, 2007 Quotesend it to "Myth Busters"....... They already proved that running a truck with the bed hatch up and locked is more efficient than running with it down, running with a mesh net, or running with a cover. My best effort at explaining it would be that it is affecting the leading edge flow of the air over your car, which means that in theory, it wouldn't change your gas mileage at all. If it does, it wouldn't change it by much. A bug guard isn't equivalent to driving with a piano on your roof. It's equivalent to driving with a nose-cover on. Really, it's not going to change much. The air's still stable as it was before, it'll just start flowing a touch differently. At much higher speeds, in the neighborhood of 70-100, you might start feeling a little shimmying as some unstable air brushes around the side of the vehicle, kind of like propeller effect on a Cessna, but I wouldn't recommend going those kinds of speeds with a Jeep anyway. And at those kinds of speeds, I don't think you'd really be concerned about gas mileage, would you?"If at first you don't succeed... well, so much for skydiving." - aviation cliche Quote Share this post Link to post Share on other sites
Beerlight 0 #7 May 17, 2007 I saw that episode! And to think I used to drive around with my tailgate down.... Quote Share this post Link to post Share on other sites
willard 0 #8 May 17, 2007 A very easy,cheap, and sufficiently accuratte way to see just how it affects your particular vehicle is a coast down test. A long, straight, smooth stretch of road is needed. An old airport runway is great, just make sure it's no longer in use. Get your vehicle up to speed, say, 60 mph, and when reaching a mark (line on the road works, post next to the road is better) put the transmission in neutral and let the vehicle coast to a stop, keeping it as straight and smooth as you can. Very small inputs on the steering wheel. Mark where the vehicle stops. Repeat several times with your bug deflector and again without to get a good sampling. This will show what changes to the drag coeffiecient (+ or -) the deflector causes. This test is accurate enough so that if there is no noticable difference in coast down distance then you need not worry about any changes in mgp as they will be very slight. BTW, make sure your tire pressures are even left-right. Quote Share this post Link to post Share on other sites
