THE next generation of Mercedes performance cars will be powered by a new V8 petrol engine making them as economical as an original Mini Cooper.

Using advanced direct injection and turbo charging the new 4.6-litre V8 is 22 per cent more fuel efficient than the current engine used by Mercedes.

It will make its debut in a new luxury CL 500 coupe later this year where it is claimed to be capable of averaging almost 30 miles per gallon - the same as a 1,275cc Mini Cooper achieved in 1964.

Exhaust emissions of 224g/km will set a new green standard for V8s.

Although the new engine has a smaller capacity than the present 5.5-litre V8, it develops 435bhp - a 12 per cent power boost.

A new 3.5-litre Mercedes V6 is also on the way which is even meaner and leaner. Developing 306bhp it takes CO2 emissions down to 177g/km, 24 per cent lower than Mercedes' present 3.5-litre engine.

The V6 will be introduced in a new S-Class next year which Mercedes claims will average 37.2mpg.

The next S-Class will also be fitted with the new V8 and eventually both engines will feature across the Mercedes range.

The engines are currently undergoing final testing at Mercedes' Bad Cannstatt works near its headquarters in Stuttgart.

As well as pressing ahead with advanced internal combustion engines Mercedes says it is also developing alternative powertrains including electric motors, hydrogen fuel cell cars and hybrids.