Compare petrol and diesel and how their performance for their respective engined cars measure up
Petrol and diesel: what’s the difference?

We know filling up a petrol-run car with diesel is a definite no-no, but do you know why? It’s because petrol and diesel are completely different fuels with different chemical compositions. Petrol is more refined than diesel and is produced first as it has a lower boiling point than diesel.

But putting aside the disparity in pump prices, is there any difference between driving a car with a diesel engine and one with a petrol engine?

The case for petrol-engined cars

Performance

Petrol engines are generally quiet and smooth, more responsive, and have faster revving and better acceleration response than diesel engines. They also usually give more horsepower for any given size of engine. The newer diesel cars may not be too far off, but petrol engines undoubtedly offer better refinement.

None can rival a petrol engine for smoothness and noise suppression. While the newer high-tech diesels are less noisy than the older models, there is still some clatter when cold or at idle.

Cost

Diesel cars are usually more expensive than petrol cars. The price of a diesel option, particularly a turbo-diesel one, can add up substantially because the diesel engine has more costly requirements in design and building stages.

In terms of upkeep, diesel models normally require more frequent engine oil and filter changes, and in many cases the service parts are more expensive than their petrol equivalents. An added cost in diesel maintenance is a fuel system service, which involves rebuilding the injectors and recalibrating the injector pump.

The case for diesel-engine cars

Performance

Almost all new diesel cars are turbo-charged, which gives them decent performance. A diesel engine is more easily turbocharged than a petrol engine as it has no fuel in the cylinder. Diesel engines have higher torque than petrol engines, which means that a diesel engine can pull a heavy load easier than a petrol engine.

Diesel engines don’t need an ignition system, so they use glow plugs rather than spark plugs which generally need to be changed every two years or so.

Cost

Diesel engines have better fuel-efficiency compared with petrol as they have a higher compression ratio. There is also a smaller “environmental” cost, as diesel cars emit less carbon dioxide since they use less fuel than petrol cars.