Guide: exhaust gas recirculation Valve removal EGR

[DeeTurbo]

Yeah because that makes sense...all the superminis making under 99 g/km CO2 and paying no road tax really rinse fuel......oh wait no they don't.

CO2 is produced by burning fuel, the more fuel you burn, the more CO2 is produced.

I'm not sure how that can be wrong?

In diesel engines

By feeding the lower oxygen exhaust gas into the intake, diesel EGR systems lower combustion temperature, reducing emissions of NOx. This makes combustion less efficient, compromising economy and power. The normally "dry" intake system of a diesel engine is now subject to fouling from soot, unburned fuel and oil in the EGR bleed, which has little effect on airflow, however, when combined with oil vapour from a PCV system, can cause buildup of sticky tar in the intake manifold and valves. It can also cause problems with components such as swirl flaps, where fitted. Diesel EGR also increases soot production, though this was masked in the US by the simultaneous introduction of diesel particulate filters.[6] EGR systems can also add abrasive contaminants and increase engine oil acidity, which in turn can reduce engine longevity.[7]
Though engine manufacturers have refused to release details of the effect of EGR on fuel economy, the EPA regulations of 2002 that led to the introduction of cooled EGR were associated with a 3% drop in engine efficiency, bucking a trend of a .5% a year increase.[8]

Taken from wiki also a lot of the new super minis have small three cylinders engines.