CNNMoney.com - Fuel saving tips that just don't work

[2003protege]

[QUOTE= ]I can think of 6 more mpg myths:

Studies have shown that drilling holes in the bottom of your gas tank leads to lower gas mileage, not higher.
All other things remaining equal, replacing a Prius with an H2 Hummer rarely results in less money spent at the pump.
When pumping your own gas into your car, there is a way to hold the nozzle trigger so that once your tank is full, an additional gallon or more spills on the ground. Contrary to common belief, this practice results in more gas wasted rather than less.
If you drive a 4 wheel drive pickup truck as a highway commuter vehicle, driving at 90 mph can sometimes waste gas. Also at these speeds, the high-lift suspensions, oversize off-road tires, and that bank of off-road spotlights all increase this effect.
If when sitting at red lights, instead of letting your engine idle or even turning it off, revving your engine to above redline just to hear the valves float may actually lead to higher fuel consumption.
Disconnecting half of the spark plug wires only causes your engine to run rough and results in no savings what so ever.
QUOTE]

hahaha..i almost choked since i was eating while reading #5

And concerning CNN's #3, fuel grade....i think it's fine if your Metro's owner's manual says premium that it's probably exaggerating, but i would think with turbocharged cars out there like the WRX that squeeze 300 hp out of a 4 cyl, you're probably not gonna get away with 87 oct. ..maybe i'm wrong about that?

[trebuchet03]

But you should never over-inflate your tires. They'll get you slightly better fuel economy because there will be less tread touching the road, reducing friction.

Someone obviously flunked high school physics.

Morbo says: That's not how friction works.

friction force = mu*force_normal

mu is a material property, not a geometric property
force_normal is dependent on mass and the angle of the road surface relative to the gravity vector.

Period


There's a high school physics demo involving a non cubical block of wood and a fish scale.... Drag the block of wood with a large contact patch - measure drag force... Now drag it on it's side (smaller contact patch) - wouldn't ya know, same exact drag force



To be fair, there is adhesion - but that's insignificant for treaded tires (compared to non treaded tires you're likely to see on a race track).

[Lazarus]

Originally Posted by Frankenstipe

I agree with number 4 a lot, I notice a lot of you over-inflate your tires for better MPG. I personally think it's just too risky and dangerous, just because it can be done doesn't mean it should be done.

Also number 2 is just retarded, sure it may not net you MPG, but it hardly costs $20 to replace the damn thing and it helps improve the life of your engine.

Here's a good thread on filters. There's a few more on the subject if you want to use the search function.

[Bror Jace]

Thinking about this s'more, it's the sheer stupidity of the article, especially that #4 piece about "overinflation" that irks me. Are there only 3 possible inflation pressures: Underinflation, correct inflation and overinflation? When it comes to the builder of the vehicle or the sidewall, which number (and they are never the same) should be the final word? These kinds of questions are never asked and (obviously) never answered. They obviously failed journalism 101 … not surprising given they work at CNN.

I run my tires about 1-2 pounds under the max sidewall pressure. Golly, am I overinflated? Now I’m all confused and afraid to get into my car. With my tires potentially overinflated, is my vehicle now a ticking bomb? If I touch my valve caps, is there danger of an explosion?

There’s a lot of confusion out there among the great unwashed masses. And everyone turning to CNN.com for information will be failed utterly.

I belong to another car forum and this article was debated at length ... especially the air filter question. The consensus is that air filters are over-sold. Problems only occur when they are neglected for 20,000+ miles. I tend to replace mine every 12,000-15,000 miles ... usually in the spring to get rid of the salt that's undoubtedly trapped in the fibers.

Anyone want to see more debate about this article is welcome to read the following:

http://www.bobistheoilguy.com/forums...34#Post1150434

[DifferentPointofView]

I don't see how running max sidewall is overinflated either. The people who made and spent thousands of dollars in research of what their tires can handle are wrong and the guys at some news station are right? give me a break

If anyone wants to know how safe it is to have your tires inflated 5psi over the limit, come with me and I'll show you how safe it is. I'll drive though potholes that bottom out the suspension, I will take roads you thought were chocked full of nails and I will take turns that make you think the tires that have "less grip" should give way.

Did you ever notice that when people do auto-cross (and if you don't know what that is you shouldn't be preaching about how unsafe over inflating your tires is) Pump up their tires to or over max sidewall? They take the tires to their breaking point, taking turns on a dime and making them heat up way more than you will driving down the highway. Do their tires bust? no, do they cause them to loose traction and spin out of control? no, because the tires provide stiffer sidewalls for better cornering and more steering response. Something under-inflated or factory inflated tires couldn't do.

Oh, and FYI, the tire rating on the door is there as a compromise between a Cadillac-like smooth ride and a rough sports car-like ride. Most people won't be driving the tires to the max, so they go by a more comfortable, bump-absorbing pressure.

Cops inflate their tires to max sidewall for best performance. If it were unsafe then cops wouldn't inflate them like this and then drive in a high-speed chase.

[Daox]

Someone posted the same thing on genvibe.com... I've just been posting links to tirerack's articles on tire pressure and how they state higher pressure gives you better handling and tire wear at the expensve of ride quality... exactly what we've always said here.