Comments on: How to Spend Less on Gas for Your Car

on 8/8/2006 At high speeds, the coefficient of resistance significantly affects the gas mileage. High profiled vehicles such as rigs or those with flat backs (Element. Scion, SUVs) create a lot of drag particularly at high speeds. To reduce drag during long distance driving, I slightly open the back window of the cab in my P/U truck. My gas mileage improve noticeably. Airplanes are streamlined with this concept in mind. The same physical principle applies to automobiles.

on 6/30/2006 Engine Braking
Car with advance engine management systems use little to no petrol when the engine is under full vacuum (engine braking). Not only does it save you some money compared to using free gear to roll down the street, it also prolongs your brake pad's life.

Window up or down
People argue that with the window down, air drag will cost you more petrol money. But in reality how much they will affect you pretty much depends on your car's aerodynamics. If you drive a sports car with a sleek body, it will affect you a lot, however, if you drives around in a box-on-4-wheels from the 70's, you might as well wind down the window as it won't affect too much.

Automatic vs. manual
Automatic tranny cars consume more fuel due to drive train loss. However, newer Toyota and Lexus cars with automatic transmissions are rated to have better fuel economy. The same goes for a lot of JDM cars with advance transmission systems and EMS that are rated to use less fuel than their manual counterpart.

Fast or slow
Driving fast certainly will cost you more petrol, but driving at 25 MPH isn't doing you any good either. What is the point of driving in 3rd gear all the time? Or accelerating so slow to get to the highest gear just because jack rabbit starts cost more petrol? The best way is to accelerate normally (follow traffic, so you won't hog the road) until you reach the highest gear and stay there. Most cars consume the less fuel in 1500-2500 RPM range.

Big engine vs. small engine
Certainly a Chevy small block will consume a lot more petrol than a 1 liter inline 4 engine. However, if you need to carry stuff or people, and drive in hilly terrain, you are better off with a higher capacity engine. It will cost you more petrol if you need to full throttle your poor little engine. Conclusion is to choose a car with an engine that suits your driving, you will save more that way.

Turn off your engine
I myself gained 20% more millage from a tank of fuel just by turning off the engine at every traffic light. My car had a 1.6 liter inline 4.

Lighten your car
Weight cost more petrol. So lighten your car. Get rid of everything that you don't need. If you can make do without seat cushions or leather wraps, then do without them. If you want to go to the extreme you can even start stripping all the carpets or sound insulation layer.

Tire and wheels
I know there are people who like big big wheels with low profile tires, sure, they look nice, but they are costing you a lot of petrol money. Bigger wheels are heavier, thus giving more rolling resistance. To save fuel, find the lightest set of rims that is big enough just to clear the rotors and calipers.

Legal issue
If you live in a place with little to no emission control laws and you don't care about the environment, then get rid of that catalytic converter. That thing is robbing power and adds restriction to the exhaust system. Same goes to air filter. You will gain more power or better fuel economy if you can reduce the air flow restriction of your engine.

on 6/30/2006 It may defy intuition, but leaving your truck's tailgate up actually maximizes gas mileage! The reason? As air passes over the top of your cab, there is a circulating pocket or bubble of denser air that pushes the high-speed air right over your bed. Leaving that tailgate down eliminates your bubble and adds quite a bit of drag, reducing mileage as much as 2 or 3 mpg.

on 3/26/2006 Take your foot off of the gas when you go down hills. It lowers the RPM'S making the engine work less hard.

on 1/4/2006 Gas weighs 7 pounds per gallon, so filling up on, say, 25 gallons is like carrying a 175-pound man in your trunk, cutting down your gas mileage. Instead of filling up, buy half a tank and the lighter weight will help you increase your gas mileage.

on 11/22/2005 Use the AC only if you can't bear the heat. And even then, only at highway speeds. When driving around town or under 40 MPH, it's perfectly fine to roll the windows all the way down to keep cool. At such low speeds, wind drag will have virtually no effect on fuel economy.

on 11/22/2005 When driving, try to keep all the windows in the car up. Not doing so creates more drag on your car and less gas mileage. Don't turn on your air conditioner, it uses more gas too.

on 11/22/2005 Look around for the cheapest gas before buying, don't just pull in at the first place you see - prices vary, often drastically from place to place.
Buying gas on a cold day (or in the early morning) will also give slightly better value for money as it is sold by volume and it becomes more dense the colder it gets. Buy a bicycle and use that for short trips (it is the most efficient form of transport known to man).

on 11/22/2005 Go to usgastracker.org and sign up for free daily e-mail with the lowest gas prices in your zip code. The e-mail has the stations name and address. I have saved as much as 20 cents a gallon.

on 11/22/2005 Studies show that fuel can evaporate from your tank if the cap is either loose or non-existent. Close the gas cap until you hear the ratcheting noise. If you've lost your gas cap (most cars now tether the caps) purchase a new one.

on 11/22/2005 Buy a "K&N" air filter. With it, you never have to change it, and they give more air (meaning you get better fuel economy and more horsepower)... VROOOM!

on 11/22/2005 One Of the best things you can do for your car in a cold day is to warm the engin when starting up, not doing so will greatly reduce engin life,

on 11/22/2005 Whenever possible, such as at red lights, use Neutral. With automatic transmissions, the engine is still working to push the car while stopped in Drive. Also, don't use the engine as a brake.

on 11/22/2005 A small engine uses less fuel.
I know it's nice to drive a V8, but its efficiency is bad (1 liter on 4 km) a 4 cylinder (some 1 liter on 24 km) will safe you lots of money and the environment.

on 11/22/2005 Always look far ahead of you and keep a safe distance from the car in front of you. This way, when you stop you can slow down and spend less time accelerating to pick up speed.