Fuel economy is based around 3 things: Engine efficiency, Rolling resistance, and Weight.
Engine Efficiency - basic
Engines just aren't as efficient as they can be directly from the factory. To ensure that your vehicle is as efficient as possible do the following:
- Spark Plugs
- Number one improvement is uprated spark plugs. The better the plug, the better the spark, which in turn allows the engine to more effectively burn the delivered fuel. From a cost efficiency standpoint I prefer the Bosch +2 or +4 plugs. I've seen (on my old Porsche 944) a 50 mile range increase just by changing to these plugs from stock.
- Plug Wires
- Now, plug wires are starting to go the way of the Dodo, many new cars have the coils directly attached to the plugs. This being said, there's still many cars that employ them. Check them periodically to make sure they are still in good condition, if possible uprate them to a larger diameter wire (e.g. go from 7mm to 8mm diameter). A good shade tree way to check your wires is to raise the hood and watch the motor when it's pitch black out. You'll see bad wires arcing across the engine. The better the plug wire, the more electricity that gets delivered to the spark plug.
- Air Filter
- The normal air filters you can buy at your local auto parts store are ok. On the aftermarket for just about any car are high performance air filters. These high performance air filters allow for greater volumes of air to enter the engine. The more air you flow into the engine, the more efficient it will run.
- Oil
- Engine oil is usually the most abused part of the car. It you go to a quick oil change place they generally use a cheap oil which breaks down quickly within the engine. If it's a new car, make sure you use a high quality synthetic from day one (e.g. the Explorer has only ever had Mobil 1 synthetic in its block). If it's an older engine, use a high quality engine oil, but it doesn't need to be a synthetic. Also, if you're switching up to a better grade of oil, use an engine cleaner for the first few oil changes to get out as much residual sludge as possible. And don't complain to me that high quality oil is expensive. First of all, your engine will last much longer. Secondly, for every dollar you put into higher quality oil that's multiple dollars less you'll put in as gasoline.
- Fuel Injector Cleaner
- I'm always amazed how few people use this stuff. Fuel injector cleaner goes through the fuel system and cleans out any residual particulate crap. This is especially true of the injectors. A perfect example. A friend had a Cherokee that just wouldn't run, it idled like crap, and it gave me fits as I couldn't decypher the problem with it. As it turns out, he'd put 70,000 miles on the car without ever running injector cleaner. After all the hours we spent farting around with the car a couple $5.00 bottles of cleaner later it ran like a champ!
- Distributor & coil
- On the off chance you have a distributor and coil on your car (most new cars do not) ensure that the distributor cap and rotor are in good shape, and are clean. These are cheap parts, replace them if at all questionable. If you have a traditional coil you can upgrade it to something like a Flamethrower one which will boost electrical output from the coil
- Battery
- Ok, you may be going "huh?" at the mention of the battery, but remember that it controls all of the electrical systems in the car. Periodicaly check the terminals for corrosion and quality of contact. Clean them and cover them with vaseline. This will help fight corrosion. The better the connection, the better all the electrical systems (such as the ignition system) will run.
Engine efficiency - advanced
- Air intake
- Engine efficiency is goverened by three things, amount of spark, amount of fuel and amount of air mixing with the fuel. As we want to reduce fuel, the other two need improving. An aftermarket air intake (particularly when paired with an exhaust) will improve fuel economy by increasing the amount of air consumed into the motor. While we laugh at cold air intakes in Arizona (since we have no cold air to intake), these sorts of improvements will pay for themselves many times over during th elife of the car.
- Exhaust
- A free flowing exhaust manifold (also known as header) and matched exhaust pipes will help the exhaust gasses flow out of th eback of the engine more efficiently. They are espcially critical for improvements when paired with an uprated air intake.
Now, the nice side effect of the engine improvements is that you'll not only have fuel economy improvements, but this will and can also improve the amount of horsepower delivered by the engine (and who's going to complain about extra horsepower?!).
Rolling resistance
Weight
Go on a diet! Not necessarily for you, but your car. If you're anything like me (wife, 2 kids and 2 dogs) you'll note that over time your car becomes a dumping ground for left behind toys, baby strollers, and junk of that nature (or in my car's case, piles of car parts). Every additional pound of unnecessary weight reduces fuel economy. Go through your car and purge it of unnecessary stuff.
Hopefully with these tips you can take a car that performs like my friend's (17 mpg) and get it to run like mine (22.5 mpg)!
Cheers!
Jody
