So you're now bored of the modest amount of power you manage to squeeze out of your seemingly pathetic car and are looking to upgrade to a more fiery number, but how do you go about it?
Well, it largely depends on the type of engine - quite often manufacturers restrict the power from one of the engines in their current line up to provide the propulsion for one of their slightly cheaper or less sporty cars. This is usually a marketing decision to prevent the migration of customers from their more premium range to a cheaper car with the same performance, but more likely to ensure decent fuel economy and reduce emissions. In this case you probably have more chance of a significant power boost, than in a car which is already extracting full beans from the engine such as the turbocharged sub one-litre engine in the Smart. So read up on your car and find out whether the engine derivative is used elsewhere. If it is, you're in luck, but where do you start?
The most common methods to increase performance cheaply include:
- Making it easier for the engine to take in air and get rid of waste gas
- Modifying the electronic engine management
- Reducing weight
Air intakes, exhausts and manifolds.
For the majority of cars, extracting every last horse from the engine isn't top priority for the manufacturer, reducing assembly costs is always high on the list. This includes making components with less complex curves such as those needed to allow a perfectly smooth flow of air into and out of the engine. The fluid dynamics of air as it enters and exits an engine is an extremely complex topic, which requires detailed and expensive computer modelling to ensure the optimum flow of air. Sure enough, less than perfect components are usually used in a cost saving exercise. Replacing such components with ones which aid the free flow of air is often a good way of ensuring the best efficiency of your engine with its current management settings. Do bear in mind that it's the free flow of air which is important - getting the fattest exhaust you can fit will probably compromise performance by not providing enough essential back pressure.
Key items to consider include air intake, air filter, intake manifold, exhaust manifold and exhaust pipe. K&N dominate the paper based filter market and Pipercross do foam varieties, both companies will provide a solution for almost every car, and will even make one to fit if you know the dimensions of the pipes. These do need cleaning, usually at the service intervals, otherwise efficiency is reduced. Getting a free flowing air intake and manifold will further increase performance and the same is true for the exhaust end. The quicker the air can be expelled the less precious power is sapped forcing it out.
Modifying the engine management.
Almost all modern engines are now controlled by electronic engine management chips. This control almost every aspect of the engine, from the spark timing and fuel air mix to the rev limit and throttle response. When determining the factory spec all kinds of factors are considered, including fuel economy and emissions. Replacing or re-programming your chip can give instant performance gains, but usually compromises in other areas and can be expensive. Bear in mind once a chip is reprogrammed it can be expensive to reset it back to defaults.
Reducing weight.
This may sound obvious, but reducing weight can be the easiest and most effective way of increasing performance. In real terms, the only figure that actually matters is the power to weight ratio. Reduce weight and you have the same effect as an increase in power and will also lead to more nimble handling. You'll be amazed how much weight can be lost from items such as rear seats, spare wheels, carpets, roof linings, sound deadening material....this list is extensive. This is only really an option if you are creating a dedicated track car, and you'll be equally amazed how noisy it can be without all this stuff inside!
