By Jim Kerr
Small can be good, especially when it comes to the engines that power our vehicles. With the price of fuel continuing to rise, automobile manufacturers are looking to build more fuel-efficient vehicles, and installing a small-displacement engine is one way of improving fuel economy: it simply takes less air and fuel to fill the smaller cylinders.
There are other advantages to small engines. They are lighter, and this helps both in fuel economy and in performance. Light engines allow many other parts of the vehicle to be lighter too: suspension parts such as springs, sway bars and control arms don’t need to support as much weight, so they can be lightened. Smaller engines need smaller cooling systems, reducing the amount of coolant in the vehicle. More fuel efficient engines can operate with smaller fuel tanks while still getting good driving range. Gasoline weighs about 800 grams per litre. Reduce the fuel tank from 80 litres to 50 and you now have 24 fewer kilograms of weight to accelerate or brake. Every little bit of weight reduction helps: for every 45 kilograms of weight you remove from your vehicle, gas mileage can increase by one to two per cent.
Small engines also improve vehicle performance. It is easy to recognize that a lighter vehicle accelerates faster – just look at motorcycles as proof of that. What many forget is that a lighter vehicle also brakes quicker. On the race track, it is usually the driver that can carry speed further into a corner and brake harder that will be able to pass. While I would definitely not recommend this technique on the street, being able to brake harder does provide additional safety.
Handling is also enhanced: lighter cars turn corners easier. On a race circuit, it is the more nimble small-displacement-engine cars that can run circles around the big block cars, except on the straights. When it comes to straight line acceleration, they have said there is no substitute for big displacement engines, but even that concept is changing.