Fuel Economy Myths

[The_Blur]

I thought this article was interesting. A common trend is that people think that freeing up horsepower or fuel economy is the same as creating them. If you add something, it was never there. If you free it up, then it was there and something got in the way.

Vehix reported. Discuss.

[Brokinarrow]

Very interesting. One thing I always do is pop my car into neutral and let it roll when going down large hills.

[knowitman]

No matter how many times I tell people to put the tailgates on their trucks, I'll still see them cruising down the interstate at 85 with the tailgate down.

[8cd03gro]

I love the people that swear by additives for performance and fuel economy. The very best additives, if you do the math, bump your overall effective octane rating by just over 1 point, but claim to make a huge difference. Such a waste of money.

[DGthe3]

I was surprised with the first one, and I had never heard of the last one. Also, they never really said that overinflating tires won't improve your fuel economy ... they just said that its a bad idea and potentially dangerous.

[bigearl]

I saw that tailgate Mythbusters. I honestly was surprised at the time, but live and learn eh? I guess not everyone has cable tv

[cab2g]

I definitely would've thought that idling was better than restarting the engine, but from now on, I'll turn the car off whenever I run inside to get something I forgot!

[The_Blur]

Originally Posted by bigearl

I saw that tailgate Mythbusters. I honestly was surprised at the time, but live and learn eh? I guess not everyone has cable tv

I thought that one proved that tailgating a semi with a trailer actually increases your efficiency. They also unintentionally proved that erratic driving kills fuel efficiency when they tried the closest distance because the driver kept adjusting speed to stay withing a certain range of the trailer.

[DGthe3]

Originally Posted by The_Blur

I thought that one proved that tailgating a semi with a trailer actually increases your efficiency. They also unintentionally proved that erratic driving kills fuel efficiency when they tried the closest distance because the driver kept adjusting speed to stay withing a certain range of the trailer.

Thats tailgating, there was also one (and maybe a revisit too) where they compared fuel economy for a pickup truck with tailgate up vs tailgate down. I'm pretty sure they also tested a tonneau cover, a plastic mesh tailgate replacement, and no tailgate at all.

[bigearl]

Originally Posted by DGthe3

Thats tailgating, there was also one (and maybe a revisit too) where they compared fuel economy for a pickup truck with tailgate up vs tailgate down. I'm pretty sure they also tested a tonneau cover, a plastic mesh tailgate replacement, and no tailgate at all.

Ya, this one- not the drafting a semi one.

[Number 3]

Well you'll start to see start/stop technology in more cars in the future. A recent article on the new MY Honda Hybrid said they increased the stop time significantly which should result in better City MPG simpy for allowing the engine to shut off. That was the biggest benefit in the Malibu Hybrid was shutting the engine off when stopped. Take your foot off the brake and the engine restarts before you can reach the accelerator pedal.......unless you have a Toyota (LOL)

The biggest impacts to fuel economy are Aero, Rolling Resistance and Mass. It's why a Corvette can get high 20s to 30 mpg on the highway. It has low mass, which reduces rolling resistence, low aero, very low in fact and I've pulled 28 to 29 easily on trips to Florida.

Look at the Volt.......all Aero. The one I drove yesterday scraped the front spoiler much easier than a regular car. It's lower for better aero. And none of the reviews that I've read talk at all about the underbody. The Volt has a full underbody aero package to smooth out the airflow under the car.

And wait until you see the Cruze ECO and some of the tricks that car has in place.

Aero is why the Myth of the tailgate exists. In practice, a flat panel like that is horrid for aero so it could lead one to the conclusion that simply eliminating a bad aerodynamic element would help.

Most modern cars have Decel Fuel Cut off. So if you take your foot off the accelerator, the engine stops sending fuel to the engine. Some OEMs are more aggressive in this area than others and you can tell when it happens. GM has not been the most aggressive in this to protect optimum drivability. So the poster that puts his car in Neutral if you have a newer car, it has probably already shut off the fuel to the engine if you have your foot off the accel. pedal.

Fuel economy is driving decisions on every program I'm involved in. It is so HUGE for the upcoming CAFE rules to simply be able to sell cars.

Here is something that I wouldn't have thought of (in line with the A/C "myth"). The Alternator, when not free wheeling, uses fuel. BMW for example has set up their new 5 Series such that in the government test, the alternator free wheels for much longer and the car gets a higher MPG rating. Obviously the Alternator has to kick in the charge the battery back up, but for a long stretch they keep it off to improve the mileage.

It's why you will see more and more Elec. Power Steering in vehicles. The PS pump is drag on the engine and requires extra HP.

Oh and they didn't include the Vortex Fuel Saver which I always found amusing.

http://vortexfuelsaver.com/

Very amusing.

[98_Camaro]

Originally Posted by DGthe3

I was surprised with the first one, and I had never heard of the last one. Also, they never really said that overinflating tires won't improve your fuel economy ... they just said that its a bad idea and potentially dangerous.

"7. Overinflating Your Tires Improves Fuel Economy (myth)"


Of course, we can also toy with the idea that it does help with fuel economy, but if Economics has taught me anything, it's that the opportunity costs simply aren't equal. Safety should never be sacrificed to save a few bucks here and there, especially when someone's behind the wheel of a 4,000lb murder weapon.
(You can see what kind of impression driving school had on me)

[Rockhead]

Reset your trip meter every second fill. you will double your mileage.

[its a syn]

on mythbusters they dimpled a car exterior like a golf ball and got something like 10% mpg increase. something about how air flows over the dimples.