mattt 29 Report post Posted January 10, 2019 Hello all I have the TD NA package (uel) + OEM 2nd cat + invidia q300 exhaust. I'm thinking of forced induction in future, but as I understand it from Mike the TD turbo requires the removal of the 2nd cat. As I need my car relatively hassle free and MOT worthy this is unfortunately not an option for me. What options are available to me? If going turbo (or indeed supercharged), would I need a more free flowing sports cat, and would the car likely pass MOT despite catless manifold? Much appreciate any responses to this "have my cake and eat it" question! Sent from my ONEPLUS A5000 using Tapatalk 1 sam534 reacted to this Share this post Link to post Share on other sites
Church 209 Report post Posted January 10, 2019 IIRC there was good deal on cossworth SC kits. Should work also with stock header with stock primary cat. Maybe contact Matt@Cossy. Share this post Link to post Share on other sites
Varelco 211 Report post Posted January 10, 2019 1 hour ago, mattt said: but as I understand it from Mike the TD turbo requires the removal of the 2nd cat. No its not a necessity, you can keep the stock front pipe, the only reason for changing it is to make the most of the turbo kit (in terms of power). So you can have your cake and eat it. Share this post Link to post Share on other sites
Delirious_ 13 Report post Posted January 10, 2019 Cosworth SC with completely stock exhaust is fine. Having a 'legal' car and avoiding any hassle come MOT was important to me. Plus, with standard exhaust you can hear the supercharger spin up, which sounds incredible Share this post Link to post Share on other sites
nerdstrike 186 Report post Posted January 10, 2019 A supercharger simplifies the situation as it doesn't mess with the exhaust manifold, but let's not forget that adding boost unfailingly increases the maintenance needs of the car. You'd want to invest in the most mature solution available to avoid issues like the HKS supercharger owners have encountered. You might also find the cats will wear out sooner if you're increasing the exhaust temperatures significantly, so best to say off high boost. Thinking about emissions testing, both a turbo and a supercharger will be on boost at testing RPMs, but hopefully the ECU will keep things clean under partial throttle and light load. I think you'd get away with sports cat + second OEM cat, but not the sports cat on its own. One OEM cat is already close to the edge. Share this post Link to post Share on other sites
BRZ-123 174 Report post Posted January 11, 2019 20 hours ago, Varelco said: No its not a necessity, you can keep the stock front pipe, the only reason for changing it is to make the most of the turbo kit (in terms of power). So you can have your cake and eat it. There is more to it than that. I have spoken to mike in the past and his advise was that the cat will get damaged quite quickly if you continue to run with it. The OE CAT cannot sustain the high flow and was not built for it. So it is not simple to solve that one. Share this post Link to post Share on other sites
Varelco 211 Report post Posted January 11, 2019 Yeah its never going to last as long as staying NA but same could be said with the stock clutch etc etc. The same can be said for the standard manifold with a supercharger, there has been a few blown out after being used on track. Share this post Link to post Share on other sites
mattt 29 Report post Posted January 18, 2019 Thanks for the replies. Who on here runs FI with cats and how do you get on at MOT time?Sent from my ONEPLUS A5000 using Tapatalk Share this post Link to post Share on other sites
Kodename47 446 Report post Posted January 18, 2019 A good secondary cat would work fine - OEM or good quality high flow. The FI will help with the cat getting up to temp. A supercharger is less power restricted by running the OEM cat or exhaust if it helps, a turbo obviously is affected by smaller pipework. Share this post Link to post Share on other sites