One way of increasing the power from your engine, depending on the car is to get your engine "remapped". This effectively means that your cars on-board computer (or ECU) has had its software changed and as a result the engine is told to produce more power.
It should also be noted that changing the software used by the car can also be referred to as chipping or flashing (the same as you might flash a new bios on a motherboard for your desktop computer).
Remaps come in stages. A stage 1 remap is only tempering the software in the car. Stage 2 may mean new exhaust system and/or other components. Here is an example of a stage 1 engine remap. You can enter your car in to that site if you'd like to see more specific details of the benefits of remapping your engine on your particular car.
- More power (BHP)
- A lot more power if your car has a turbo especially
- More torque
- Better engine efficiency (but not normally better fuel consumption due to the increase in power)
- Often a sportier feel to the car
- May be expensive
- Other components may be built to cope with the extra power and torque unless they are also upgraded
- You must notify your car insurance provider on most policies or you could risk not being covered in the event of an accident (at least in the UK)
- It will void your warranty assuming you still have one (see note below)
Note: One interesting thing about that last point made was that a stage 1 remap normally consists of only a software change. What this means is that if you car to the official car dealership (with most manufacturers, I know this for a fact with VW) is that when you take it in for a standard service, your software changes will show up as an error and they will reset your software for you back to factory default as part of their service. This means that they have (accidentally) reinstated your warranty as there is now no evidence that you would have tempered with it to begin with!
Never service a car at the dealership unless you want to loose your remap!
Note: You may be surprised at the amount of car manufacturers that will reduce the power that an engine produces to improve fuel consumption as well as use that same engine on more of their cars. You can then make use of this extra power when you have your engine remapped.
Note: This is of course only applicable to engines that have an ECU of course.
Good source of images for a chip replacement.