RedScare Posted June 6, 2008 Share Posted June 6, 2008 I would think your mileage would improve, although slightly, as it gets hotter (not accounting for a/c usage at least). do you think that has anything to do with it? Wind resistance is slightly less with the less-dense warm air, and O2 levels shouldn't be hurt because there are sensors that keep that where they need to be anyway. I also think wind itself plays a bigger part that you would think. If I can feel my car being blown around, it definitely affects the power/efficiency I'm getting.I don't think warm weather (90 degrees) has been shown to improve fuel efficiency significantly over cool weather (70 degrees). In fact, running the AC tends to decrease mileage by 1 mpg, so the current hot weather should have hurt my mileage, as I cannot turn off the AC for as long an interval as previously.Wind, however, is a big deal. I know this from my cycling experiences (headwinds wipe you out, tailwinds let you ride forever), as well as seeing the decreased mileage from driving faster (increased wind resistance). Really, though, out of all of the small tricks and big ones, the only thing that made a big difference is average speed and aggressiveness in driving style. Driving 60 mph or below is the biggest. Cutting out aggressive driving in city driving is also big. Everything else adds a little or is not even noticeable.EDIT: Oh, and the difference between 19.7 mpg and 20.3 mpg could be as much from not filling the tank completely as anything else. I'll bet my next tank only gets 19 or so. Link to comment Share on other sites More sharing options...
BryanS Posted June 6, 2008 Share Posted June 6, 2008 I would think your mileage would improve, although slightly, as it gets hotter (not accounting for a/c usage at least). do you think that has anything to do with it? Wind resistance is slightly less with the less-dense warm air, and O2 levels shouldn't be hurt because there are sensors that keep that where they need to be anyway. I also think wind itself plays a bigger part that you would think. If I can feel my car being blown around, it definitely affects the power/efficiency I'm getting.Regarding wind... Mythbusters did an episode of tailgating 16-wheel trucks and riding in their slip stream. The results were dramatic; I think up to 20 to 30% improvement in fuel efficiency.It is wind resistance that drives down your mileage, and it increases with the square of your speed; hence, driving at 80 mph, your drag on your car is almost twice (1.77) what it is at 60 mph. Your car has to work much harder, reacting against drag at higher speeds. That's why it is also important to have a "sleek" profile. With trucks and SUVs, you might as well just be pushing a barn door through the wind. Link to comment Share on other sites More sharing options...
RedScare Posted June 6, 2008 Share Posted June 6, 2008 Regarding wind... Mythbusters did an episode of tailgating 16-wheel trucks and riding in their slip stream. The results were dramatic; I think up to 20 to 30% improvement in fuel efficiency.It is wind resistance that drives down your mileage, and it increases with the square of your speed; hence, driving at 80 mph, your drag on your car is almost twice (1.77) what it is at 60 mph. Your car has to work much harder, reacting against drag at higher speeds. That's why it is also important to have a "sleek" profile. With trucks and SUVs, you might as well just be pushing a barn door through the wind.Makes me wonder, is it better to speed up to draft a semi, or go 60 with no drafting possibilities. I have thought about speeding up to catch them. Maybe I will test the theory. Link to comment Share on other sites More sharing options...
20thStDad Posted June 6, 2008 Share Posted June 6, 2008 I only was postulating the warm weather theory because I know that you can hit a golf ball a good bit farther when it's hot as hell versus cold. It's also much easier to take off in an airplane in cold weather due to air density. The difference between 70 and 95 might not be much, but 40 to 90 I bet you can feel it. Not in engine performance, I'm just talking about wind-less air resistance.No doubt on the cycling-wind reference. Me and the wife did the MS150 last year, and after a few Saturdays with 20 mph headwind and infinite cursing, I checked the wind directions before going out on a training ride. So keeping that in mind, we should strive to line ALL interstate with trees, both in the median and sides. Not only is it a visual plus, but it'll cut the wind down and help our economy. If only it were easy to get mature trees quickly...or any trees in some areas like west Texas. Link to comment Share on other sites More sharing options...
CDeb Posted June 6, 2008 Author Share Posted June 6, 2008 Makes me wonder, is it better to speed up to draft a semi, or go 60 with no drafting possibilities. I have thought about speeding up to catch them. Maybe I will test the theory.I have thought about this. Another thing to consider, though, is that by drafting a semi, you're going to have to get pretty close to them, meaning you're going to have to break and accelerate more than you would if you were keeping more space, which will offset some of your gains. This doesn't even account for the safety (or lack thereof) of the maneuver.No doubt on the cycling-wind reference. Me and the wife did the MS150 last year, and after a few Saturdays with 20 mph headwind and infinite cursing, I checked the wind directions before going out on a training ride. So keeping that in mind, we should strive to line ALL interstate with trees, both in the median and sides. Not only is it a visual plus, but it'll cut the wind down and help our economy. If only it were easy to get mature trees quickly...or any trees in some areas like west Texas.One thing that helps mitigate this is the "corridor effect." If you have a bunch of vehicles on a freeway, they're all pushing the air in the same direction, which creates a decent amount of air movement in the direction of traffic flow, cutting down your wind resistance. Link to comment Share on other sites More sharing options...
ricco67 Posted June 6, 2008 Share Posted June 6, 2008 http://ap.google.com/article/ALeqM5iR8_acX...PIrPBgD913S9480India and Malaysia axe fuel price subsidies.Could be good news for US drivers.It is excellent news to be honest with you. I think that the citizens of India and Malaysia are going to seriously curtail their usage, which will help a bit. There are a number of other countries that subsidize fuel prices and I can imagine that it is impacting them. I can imagine how much of a pain it is for Iran since they have very limited oil refining capability and heavily subsidize their fuel. There were riots in the streets when the price jumped and are now rationing in some major cities. Link to comment Share on other sites More sharing options...
jm1fd Posted June 6, 2008 Share Posted June 6, 2008 The difference between 70 and 95 might not be much, but 40 to 90 I bet you can feel it. Not in engine performance, I'm just talking about wind-less air resistance.LOL I've FELT the power increase in my vehicles in cold weather, but I've never felt a reduction in drag in hot weather. I suppose the drag reduction would, in theory, be present, but I know for a fact the impact of having more air and fuel in the cylinders in cold weather is much more pronounced. Link to comment Share on other sites More sharing options...
BryanS Posted June 6, 2008 Share Posted June 6, 2008 I have thought about this. Another thing to consider, though, is that by drafting a semi, you're going to have to get pretty close to them, meaning you're going to have to break and accelerate more than you would if you were keeping more space, which will offset some of your gains. This doesn't even account for the safety (or lack thereof) of the maneuver.One thing that helps mitigate this is the "corridor effect." If you have a bunch of vehicles on a freeway, they're all pushing the air in the same direction, which creates a decent amount of air movement in the direction of traffic flow, cutting down your wind resistance.Mythbusters followed a semi truck at 150 feet, then 100 feet, 50 feet, and finally 2 feet. Even at 150 feet - you get some benefit. The most was gained by driving 2 feet behind. Good luck being brave enough to do that!The "corridor effect" is really nothing more than the cars in front of you pushing the air out of the way, much in the same as following a semi truck. Link to comment Share on other sites More sharing options...
houstonmacbro Posted June 6, 2008 Share Posted June 6, 2008 Isn't that the same as tailgating and isn't it illegal (not to mention dangerous)? Even if it does save gas? Link to comment Share on other sites More sharing options...
BryanS Posted June 6, 2008 Share Posted June 6, 2008 In discussing hot weather, cold weather, drag, following someone, etc... The equation for Drag isD = 1/2 * rho * v^2 * Cd * AWhererho = density of airv = your velocity (forward speed)Cd = Coefficient of dragA = Cross sectional areaAs can be seen in the equation, it is velocity, the speed at which you drive, that is the dominant factor, because it is squared (multiplied by itself).The density of air does not vary significantly, with temperature (for our purposes), http://en.wikipedia.org/wiki/Density_of_airBottom line: your fuel economy is directly related to how fast you drive and the drag you impart onto your vehicle as a result - than any other factor such as air temp, whether or not you have a clean air filter, tire inflation, you name it. The only way to reduce drag on your vehicle is A.) Slow down (reduce v in the equation), or B.) Follow closely behind someone in front of you (which your are effectively reducing your cross sectional area). Your Cd is fixed and a function of the car or truck you drive.Anything else you do is just gimmicks, or won't yield anywhere near the savings of slowing down or following someone. Link to comment Share on other sites More sharing options...
RedScare Posted June 7, 2008 Share Posted June 7, 2008 GasBuddy.com is showing that the national average gas price is now $4.00. Houston is still around $3.82. Link to comment Share on other sites More sharing options...
houstonmacbro Posted June 7, 2008 Share Posted June 7, 2008 GasBuddy.com is showing that the national average gas price is now $4.00. Houston is still around $3.82.And the freeways are still just as packed. Link to comment Share on other sites More sharing options...
WesternGulf Posted June 8, 2008 Share Posted June 8, 2008 GasBuddy.com is showing that the national average gas price is now $4.00. Houston is still around $3.82.Sounds like Houston is still pretty spoiled. I drove to Safeway in San Francisco and I was very much on E. The closest gas station which was a shell had gas for $4.70. The usual around the Bay Area seems like around $4.35 to $4.40. I caught on very quickly on driving slow though. Link to comment Share on other sites More sharing options...
RedScare Posted June 8, 2008 Share Posted June 8, 2008 Since GWB's begging for more oil fell on deaf ears, the US decided to ask for help, apparently believing that a "Coalition of the Whining" is more effective than singular whining. Among the more memorable quotes from the article..."It's not good for producing nations to see the U.S. struggling economically. They depend on us to be a significant engine in world economic activity," U.S. Energy Secretary Samuel Bodman said.Apparently, our hyper-consumption is considered by our government to be our gift to the world.Or, perhaps not. Link to comment Share on other sites More sharing options...
houstonmacbro Posted June 8, 2008 Share Posted June 8, 2008 Do if I understand this tagline, the price of gas hit TWO record highs this week?Wow.***NEW YORK (CNNMoney.com) -- Gasoline rose to a milestone mark Sunday as the national average compiled by motorist group AAA reached $4 a gallon for the first time. The national average for regular unleaded rose 1.7 cents to $4.005, according the daily measure on the group's Web site. That surpassed the previous record of $3.989 set Thursday.Full article here: http://money.cnn.com/2008/06/08/news/econo...=rss_topstories Link to comment Share on other sites More sharing options...
jm1fd Posted June 15, 2008 Share Posted June 15, 2008 Wow....its a miracle! You and a couple guys with some riceboy go-fast parts have managed to do what thousands of engineers and billions of dollars couldn't! Our energy related national security problems are now a thing of the past....somebody call Washington and let them know....quick!! Link to comment Share on other sites More sharing options...
RedScare Posted June 15, 2008 Share Posted June 15, 2008 A 43 mile test. Wow, that's some rigorous testing. Grear job! Link to comment Share on other sites More sharing options...
BryanS Posted June 15, 2008 Share Posted June 15, 2008 Simply amazing. What are you doing to the vehicle, engineering-wise, to achieve such results? Making those V-8 engines run as if they were 100 hp 4 cylinder engines? Looks like a lot of people are in for a big rip off. But based on some of the vehicles in your video... people have already wasted quite a bit of money... so why not. Link to comment Share on other sites More sharing options...
CDeb Posted June 18, 2008 Author Share Posted June 18, 2008 The President, today, on energy:http://www.whitehouse.gov/news/releases/20...6/20080618.html Link to comment Share on other sites More sharing options...
musicman Posted June 18, 2008 Share Posted June 18, 2008 Pelosi: Link to comment Share on other sites More sharing options...
lockmat Posted June 18, 2008 Share Posted June 18, 2008 The President, today, on energy:http://www.whitehouse.gov/news/releases/20...6/20080618.html"And behind those prices is the basic law of supply and demand."- Prez BushI thought I've been hearing lately that that statement is false, or in the least, not entirely true? --------------Some of that energy comes from unstable regions and unfriendly regimes. This makes us more vulnerable to supply shocks and price spikes beyond our control -- and that puts both our economy and our security at risk. Amen!--------------Yet it has been nearly 30 years since our nation built a new refinery, and lawsuits and red tape have made it extremely costly to expand or modify existing refineries. The result is that America now imports millions of barrels of fully-refined gasoline from abroad. I was not aware this was the issue behind the complaint of not having built any in so long.--------------One last bit of commentary I'd like to add...Republicans want to increase production to lower prices. So the oil companies make a buck, so what?!Dems want to tax the oil companies which in turn will increase the cost of production. Now how is THAT going to make oil go down? Link to comment Share on other sites More sharing options...
MidtownCoog Posted June 18, 2008 Share Posted June 18, 2008 Obama was quoted yesterday that more drilling would only add to Exxon's profits.And he's still for his "Get Even with Oil" tax. Angry man. This issue alone could kill any chance he had a being the next Prez. Link to comment Share on other sites More sharing options...
CDeb Posted June 18, 2008 Author Share Posted June 18, 2008 This issue alone could kill any chance he had a being the next Prez.It would, if McCain was showing any interest at all in actually winning this election. At least he finally is coming around on OCS drilling. Link to comment Share on other sites More sharing options...
lockmat Posted June 18, 2008 Share Posted June 18, 2008 Obama was quoted yesterday that more drilling would only add to Exxon's profits.Boo hoo. This is America. The pursuit of money...errr happiness.I don't care if someone is going to make money. Good for them. They're supposed to. I'm for lowering prices on my/America's end. Link to comment Share on other sites More sharing options...
BryanS Posted June 18, 2008 Share Posted June 18, 2008 It would, if McCain was showing any interest at all in actually winning this election. At least he finally is coming around on OCS drilling....or if the whining Republican base would actually support the man. I've heard from many Republican friends of mine (shock!) that they will not vote for him. When I ask why, they reply "he's too liberal." What? He is the nominee of your party! He's just the figurehead of the machinery you want to run things! And you still won't vote for him? Nuts. Link to comment Share on other sites More sharing options...
MidtownCoog Posted June 18, 2008 Share Posted June 18, 2008 No different than the Dems who supported Hillary who say they won't vote for Obama.Both parties have whiners. Link to comment Share on other sites More sharing options...
jfre81 Posted June 18, 2008 Share Posted June 18, 2008 I drove the car today for the first time since Monday morning....and I missed taking Metro. Even the 1/3-mile or so walk to the nearest inbound stop.Exercise isn't so bad. Link to comment Share on other sites More sharing options...
RedScare Posted June 20, 2008 Share Posted June 20, 2008 Hmmm, so $3.00 and $4.00 gasoline DOES have an effect on driving habits.BTW, as I drove up I-45 tonight, the entire freeway was moving at 60 mph...all 4 lanes! First time I have ever seen that. It sped up a bit by FM 1960. Link to comment Share on other sites More sharing options...
jfre81 Posted June 20, 2008 Share Posted June 20, 2008 Hmmm, so $3.00 and $4.00 gasoline DOES have an effect on driving habits.A couple weeks ago, Saturday night, I made it from Briar Forest to 610 on Westheimer in all of 20 minutes. Including sitting at one whole entire red light at Post Oak. I was amazed.The stops were packed for the 82 bus though. Link to comment Share on other sites More sharing options...
houstonmacbro Posted June 20, 2008 Share Posted June 20, 2008 So it leads me to ask, were people just driving places for no reason? I mean, if traffic is reduced because of gas, then some people were probably just on the roads cruising around for no good reason. People that still MUST get somewhere are probably still on the roads. Link to comment Share on other sites More sharing options...
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