In this instructable i'll give you some tips of how to improve your car efficiency in little things that you never notice.

This is my first instructable, you can bear me with my english, because I'm spanish and I can make some little mistakes

Step 1: 1. Let the Car Warm for Itself While You're Driving

Don't let the car for a while idling for warming, you can drive wherever and by the time, your car will get warm by itself, and you'll save, time, gas and you won't emmit so much gases to the atmosphere.

Step 2: 2. Drive Responsively

Street roads, aren't for racing. Every traffic signal is designed to go for a determined speed to reduce pollution, noise, and increase safety. Driving with a little common sense, you'll gain in safety, in pollution and in police fines.

Maybe sound like grandpa drives, but this way, you'll save gas, and you won't emmit so much gases, and car's parts won't get worn so fast. Doing burnouts, heavy stops, and heavy starts, you're losing money without realizing.

If you want to race, go to a circuit, with a few friends, and race there, there's no speed limit, and i'm sure, you'll have a great time playing with your car with your friends. And a day of action with your car, doesn't matter if you emmit gases, worn parts or waste money, beacuse is only a day, a fun day, as a beach day or something, not an every day drive :P

Step 3: 3. Change Gear

In manual transmissions, people are in the order to change gear about 2500-3000 rpm on petrol, and 2000-2500 in diesel engines.

I have a '95 Ford escort with an 1.6 EFI engine, and i usually change gear in order of 2000-2500. the car has the enough power to keep dragging the weight of the car without spending more gas that's necessary for driving.

In diesel engines, the peak of par is at the order of 2000 rpm, so, i supposed, that the effect of changing a petrol engine in 2000-2500 rpm, in a diesel would be the order of 1500-2000 rpm, in the maximum par range, the zone that the car makes the maximum transfeering power to the wheels, so, in diesel, is even, more efficient

Sometimes, when I'm starting to run out of fuel, i change gear in orders of 1500 rpm. sounds kinda strange, but the car stills going forward and I procure spend the less gas as possible.

Maybe the car won't be enough warm, but is a great way to optimize the fuel use at the maximum level

Step 4: 4. Aerodynamics

Improving aerodynamics is a factor that determines, in a medium wave, the efficiency of the body of the car.

Improving this aerodynamics, you'll gain in less force that has the car to make to drag his own air friction, in a consequence, more gas spending, because the more force has the car to make to go forward.

Ok, leaving away this technical explanation (yes, I'm a car technician, what you want me to do :P) i'll show you some little tricks that make some reduction of the aerodynamic force that goes against your car.

that's a little guide that shows the amount of gain or losing aerodynamic force. Gain means, more gas spending, and losing force, less gas spending

lowering the car 30mm -5%
flat wheel covers -1 to -3%
wide rims + 2 to +4%
windows at the same level of the body -1%
filling gaps (doors, windows...) -2 to -5%
underbody shape (as flat as possible) -1 to -7%
retractable lights + 3 to +10%
side mirrors +2 to +5%
air flow through the engine bay and
radiator +4 to +14%
brake ventilation +2 to +5%
ventilation of the interior +1%
open windows +5% (notice that the air conditioning,
increase more the dragging force of the car
against him, so is preferible to go with
open windows instead of A/C)
open roof + 2
surf board in roof +40%

this board are approximations of the real values, because are lots of dependants that are involved in the modification of this values.

Step 5: 5. Some Mistakes About Car Efficiency Tips

You usually heard that some ways to spend less amount of fuel is, for example, turn the engines in stops, if are longer than 30 seconds. Well, is true that you save some gas stopping the engine, but that's not true as people believe.

In carb engines, the theory is false, because carbs need an amount of fuel to get the car started, i mean, a rich mixture into the engine, to get a correct startup.

In an EFI engine, the theory is correct, because injectors, don't need that amount of fuel as carb engines need, the CPU constantly calcules the correct amount of fuel

But in real life is completely wrong, because the engine needs lubrication and if you're constantly starting and stopping, the contrast of temperature, of cold-hot-cold-hot, it affects to the engine durability, because happens the same thing as the desert, days are extremely hot, and nights extremely cold, that's the reason of the sand, the rocks crack, and crack again, making that "mini rocks" that's the sand.

That's one of the consequences.

Another is, if you start and stop the car, the piston is hot, because the heat of explosions, the piston expands, and needs the lubrication of oil to make a wall that separes the hot piston with the cold block. Ok, so what happens if you cut the oil flow inside your engine?

You're always see on winter people that get sticked his tongue in a frozen metal part when they lick them. In the engine happens somehow something similar, the piston is the tongue and the block the frozen metal, so you can throw away your engine, because the piston is welded to the block, and you can't do nothing for save it, even the cranckshaft, because as the repentine stop, the most probably is that the crankshaft breaks and make a very cool mess.

Well, as I say in step one, that's my first instructable, thanks for watching! all the comments, and constructive crytics are accepted ;)