Cars that emit above 225g/km CO2 will now get charged £25 each time they enter the congestion charge zone.
Transport for London expects 33,000 vehicles to be effected by the £25 charge each day.
Cars with CO2 emissions between 120-225g/km will continue to pay £8 per day.
The measures could add up to £6,500 in annual cost per demonstrator to dealers retailing specialist marques such as Porsche, Bentley and Ferrari within the Congestion Zone. Those carmaker's ranges currently all exceed the 225g/km ceiling.
The change will officially start on October 27 and is part of a package of measures that Ken Livingstone, Mayor of London, has introduced to cut London's carbon emissions by 60% within 17 years.