Catalytic converters do wonders for the environment by capturing toxins from a vehicle’s exhaust before they enter the atmosphere.
However, ‘cats’ also reduce a car’s performance by severely restricting exhaust flow. What’s the ideal solution then?
Well Swedish marque Koenigsegg has pioneered a patented catalytic converter which it says frees up some 300 hp compared to a standard setup, allowing the firm’s models to deliver well over 1,000 hp.
Rather than simply using a catalytic converter fitted after the turbocharger, Koenigsegg uses a small ‘pre-cat’ on the wastegate. The main turbo passage of the firm’s engines can therefore be blocked off on start-up, allowing the turbocharger itself to warm up much quicker. When the main catalytic converter is sufficiently heated, a valve behind the turbo can be opened sending exhaust gases straight through the main cat rather than the small ‘pre-cat’.
What this effectively means is that there isn’t a catalytic converter always impeding the exhaust, therefore improving air flow and allowing the company to reliably and safely turn up the boost pressure, enough to add some 300 hp.
Simply removing a vehicle’s cat is the easiest way to avoid exhaust flow restrictions but it is illegal pretty much everywhere. Thankfully for the average consumer, high-flow cats are available for many different cars, promising to provide the best medium between performance and environmental friendliness.