Cfb86 2 Report post Posted September 15, 2021 So been on the search for catted headers and don’t really want to pay £1000+ I came across a website called “directfitexhaust” their headers look good but does anyone know anything about them? website seems okay but there’s nothing been said anywhere about them or their products If not then can someone point me in the right direction with catted or decat headers 😁 I am keeping 2nd cat, just worried about MOT if I went decat 🤣 TIA Share this post Link to post Share on other sites
Neil-h 29 Report post Posted September 15, 2021 Honestly you've got nothing to worry about if you're keeping the main cat, the pre-cat doesn't do an awful lot. I've had a TD manifold on my car for several years now and it's passed the emmissions test with no problems at all, in fact it passes easily even after i fitted the supercharger. Share this post Link to post Share on other sites
Cfb86 2 Report post Posted September 15, 2021 27 minutes ago, Neil-h said: Honestly you've got nothing to worry about if you're keeping the main cat, the pre-cat doesn't do an awful lot. I've had a TD manifold on my car for several years now and it's passed the emmissions test with no problems at all, in fact it passes easily even after i fitted the supercharger. Really? Maybe I should just go decat then, thank you! Share this post Link to post Share on other sites
Neil-h 29 Report post Posted September 15, 2021 Yup, there's tonnes of people on here running various aftermarket manifolds with out the pre-cat with no problem at all. The only point it can get a little iffy is if you fit a higher flow cat but then that's just one of those things. If memory serves me from the good old days of Subarus, the pre-cat is only there to get the car under a particular level for type approval. The emission threshold for the MOT is actually significantly higher but they have to come from the factory with the pre-cat as that's what they type approval was awarded with. Share this post Link to post Share on other sites
McDude 40 Report post Posted September 16, 2021 18 hours ago, Neil-h said: Yup, there's tonnes of people on here running various aftermarket manifolds with out the pre-cat with no problem at all. The only point it can get a little iffy is if you fit a higher flow cat but then that's just one of those things. If memory serves me from the good old days of Subarus, the pre-cat is only there to get the car under a particular level for type approval. The emission threshold for the MOT is actually significantly higher but they have to come from the factory with the pre-cat as that's what they type approval was awarded with. Yes - the close coupled cat is to pass homologation. It's there because this is tested starting with a cold engine under much stricter test conditions and getting cat light off is critical to passing (how strict this is depends if you have a stage 5 or stage 6 car). MOTs are done on hot engines with hot catalysts and basic test kit so you'll pass with an underfloor only. The majority of emissions are created at cold. Once hot a modern gasoline engine with a catalyst is a remarkably clean bit of kit. So it is a moral question - are you okay removing a piece of tech that is there to protect the environment even though you won't get in trouble for it? How much it hits the environment depends on what percentage of your time is run cold vs warm. I'm not judging or telling you what to do - just letting you know that you will be contributing a few more pollutants into the atmosphere and if you are okay with that then have at it. Your MOT tester will not call you out. Share this post Link to post Share on other sites
MartinT 514 Report post Posted September 16, 2021 3 hours ago, McDude said: it is a moral question - are you okay removing a piece of tech that is there to protect the environment even though you won't get in trouble for it? How much it hits the environment depends on what percentage of your time is run cold vs warm. I'm not judging or telling you what to do - just letting you know that you will be contributing a few more pollutants into the atmosphere and if you are okay with that then have at it. Your MOT tester will not call you out. Very good answer. I would add to that that you would usually get a tune to go with any decat manifold (you have to, to avoid the lack of O2 sensor causing check engine). A really well-developed map will give you a much cleaner burn than the manufacturer's stock tune, which has to account for lack of servicing, poor fuel and oil, different weather etc. I say this with confidence as my fuel economy with a supercharger and good ECUTeK tune is better than it was in stock form. Share this post Link to post Share on other sites