In Hypermiling: Getting Started, I offered the idea of covering the most distance in the same amount of time while using the least amount of fuel as possible. As mentioned, I increased my average city mileage from 21 mpg to 26 mpg (and sometimes higher) by following these steps, the first two of which are easy to do:

1. Accelerate Slowly

Nothing kills gas mileage faster than rapid acceleration. Think of it like riding a bike. It’s a lot easier to start slow and gradually pick up speed then to rocket off the line in the first few feet.

2. Constant Speed

Engines love working at a consistent rate. Pick a speed and stick to it, and only deviate if conditions require you to. This both maximizes fuel economy and decreases wear on engine parts.

3. Reduced Braking

Braking is the necessary evil that keeps us from rolling/smashing into things. The key is to not eliminate stopping altogether, but rather to decrease the number of times you touch the brakes. Here are some tricks you can use to reduce the number of times you use the brakes. More...

“You have got to be kidding me, four dollars and twelve cents a gallon for regular gas,” I exclaimed as I passed the local gas station on my way to work last week. For a brief second, I regretted having purchased a car that only gets about 22 mpg in town, instead wishing I had bought a used 2000-2006 model Honda Insight, which gets a Prius pulverizing average of 66 mpg. I then remembered that while I have infinite respect for anyone who drives the original Insight, I would have to give up what I love about my car—It’s fun. This is a situation that many people have found themselves in over the last few years: Driving big thirsty cars, with fill-up costs that are slowly burning a hole in their owners’ wallets. So what do you do?

Let’s rewind a bit back to when I bought my car. The year is 2008, it’s summertime in California, gas prices are nearing the $5.00-per-gallon mark, and I am a first-time car buyer. Like any young Californian male, I’m looking for something that’s fast and fun, but can still carry a couple of surf/snowboards. While I still enjoy being a not-insignificant drain on my parents’ income, I do make a conscious effort to look at vehicles that don’t go through fuel faster than a burning Iraqi oil field. After all, I will soon have to start paying for gas out of my own income. In the end, I settled on a brand new ’09 Mitsubishi Lancer GTS (manual) with 168-hp engine and a mpg rating of 21/29—all for a great price.

Okay, we can now fast forward to today or, rather, last week. Now what do you do if you have a car that the government says should get 21 mpg city but you want better gas mileage? Most people assume there really isn’t much they can do, so they waste their money by selling their old car and buying a new, more efficient one. Trouble is, we are still in a recession and most people don’t have that kind of liquidity at the moment. The solution is very easy: Hypermile. More...

It’s the story that won’t go away––oil prices are edging up again, and everyone is frantically looking for ways to save gas. Buying a new, more fuel-efficient car isn’t the answer unless the payments on it are less than the ones you’re paying on the car you already own, so the trick is getting the best mileage out of whatever is in your driveway right now.

There are several things you can do right away without changing your driving habits. Start by taking everything out of the car that doesn’t need to be there––all that stuff in the trunk, those removable fold-down rear seats no one ever sits in, that set of barbells you’ve been meaning to take to the Goodwill store. Some people recommend never filling the gas tank above halfway to save the power needed to haul around the extra gas.

The state of your car’s tune can affect its gas mileage. Check your tire pressure. Low pressure means more drag, and more gas used turning the wheels. Make sure your air filter is clean, and if you haven’t looked at your spark plugs in a while––or ever––now’s the time to see if they’re in good condition. More...

Before we talk about direct fuel injection, allow me to describe the older-style automotive fuel injection. It’s what we used to call EFI or electronic fuel injection. (That was to distinguish it from mechanical fuel injection, which debuted around 90 years ago.) EFI is still in use in most new cars.

With this system, fuel was squirted into the intake flow upstream of the intake valve. That meant the gasoline bounced off the open intake valve. Some of it wound up against the cylinder wall, where it couldn’t burn efficiently. Other bits of the fuel mist swirled around in the combustion chamber in an imprecise manner. Also, once the intake valve closed, no more fuel could enter the cylinder.

On the plus side, the old-style injectors operate in the comparatively cool and low-pressure world away from the combustion chamber where burned fuel can exceed 1,300 degrees. The old system produced excellent power, low emissions, great drivability, long life and good fuel economy. This is especially true compared to the carburetors they replaced.

However, with customers demanding more power and governments requiring better fuel mileage, engineers at many auto companies have stepped up to direct fuel injection. With direct fuel injection, fuel is injected directly into the combustion chamber at almost 3,000 pounds per square inch.

Thanks to advanced computer control, fuel can be squirted into the combustion chamber at any point in the cycle. Fuel can be added well after the intake valve has closed or the compression stroke has begun (which is why direct fuel injection needs its super-high pressure). Precise timing of the fuel injection maximizes economy and power. More...

Engineers may be working on amazing leaps in fuel mileage in research and development labs and on secret proving grounds. However, from what we see at new-car introductions (and during some peaks into R&D centers), I’m expecting a collection of 100 things that combine to produce an improvement of 10 miles per gallon. It’s doubtful that one single thing will produce a 10- (or even five or two) mpg jump.

Low-rolling-resistance tires and electric power steering are some of the new-tech features currently in production that offer improvements of less (often far less) than one mile per gallon.

The variable-displacement oil pump in the 2011 Chevrolet Cruze is another example of engineers’ hard work to produce what most see as an incremental gain in fuel mileage. (Even the mileage nerds may not see this or the other small improvement gains. A high percentage of ethanol in the fuel will easily hide a large group of incremental improvements.) More...