s4marsh
Registered User
i'm just thinking of different exhuast options and have been thinkin about gutting my precats asap,but when talking to a audi mechanic/600bhp audi owner he said removing the main cats would have more benefit which is obvious so looking at this picture above can anyone tell me what exactly the main cats are doing in relation to the engine management or making lights appear on the dashboard as the main cats are beyond the lambda probes so should have no effect if i leave the pre cats in as it looks to me like they're doing the work of cleaning the gases and reporting info to the ecu??? am i wrong????i know emmisions next mot time are the issue but thats ages away and refitting them easily enough the way i plan to delete them. whats peoples thought on the subject???