question about catalytic converter on touring race car

[Scania]

WTCC 320si



CTCC Civic 1.6T (TC2 Engine)



most of works team racing touring car are put a twin catalytic on the exit of exhaust, why they do this & y don't just make it direct exhaust without catalytic?

[Pieoter]

It is in the rules. Article 263 of Appendix J

"The exhaust system is free downstream of the turbocharger. All vehicles must be equipped with a homologated catalytic converter, the position of which is free. The exhaust gases must, at all times, pass through the catalytic converter"

[Greg Locock]

and the gas has cooled down by the time it reaches the tailpipe, so the velocity through the cat will be less, so the backpressure will be less.

It also stops spiders from crawling up the exhaust.

[Greg Locock]

Racers > rulemakers

That is so funny, all the rulemakers have done is increased the cost of the car, made them weigh a bit more, and been politically correct

The effect on emissions will be almost zero.