Question for the E30 exhaust system gurus

[GarrisonHale]

Im building a stroker motor from an m20, the final product will be ~3.1L. Do cat converters have a significant impact on the overall performance? Im not worried emissions tests b/c my car will most likely not be tested.appvalley tutuapp tweakbox

[DanThe]

Depends on the quality of the cat really, anything decent will be very expensive so if you don't need to reduce the emissions don't bother

[Kedge]

As catalytic converters weren't a requirement in the UK until 1992 I doubt many, if any, UK E30s had them fitted here.

But by all accounts, cats do impact performance as they slow down the rate exhaust gases can escape. If you don't need to fit one I wouldn't bother.