Danny.BRZ 2 Report post Posted August 11, 2021 I’ve got litchfields old brz it has a milltek primary cat back exhaust on it (secondary cat delete) and it seems to be having issues with emissions on the MOT. The car has passed every year since the exhaust was on, any reason why it would be over on the emissions? Share this post Link to post Share on other sites
BRZ-123 174 Report post Posted August 11, 2021 it could've been their test car and they might've done a lot of testing on it. Does the car have both cats on it? The Cats might have perished. The easiest way would be to look for a used OE manifold as many people change to aftermarket manifolds. Replace that and you should be good. Share this post Link to post Share on other sites
Danny.BRZ 2 Report post Posted August 12, 2021 13 hours ago, BRZ-123 said: it could've been their test car and they might've done a lot of testing on it. Does the car have both cats on it? The Cats might have perished. The easiest way would be to look for a used OE manifold as many people change to aftermarket manifolds. Replace that and you should be good. Yes mate, the secondary cat was deleted with the milltek system but I have seen people on here running the system and passing everytime like my car has in the past. Thanks for the suggestion I will look into it, would it be as simple as one of the sensors has gone down? Share this post Link to post Share on other sites
BRZ-123 174 Report post Posted August 12, 2021 It is definitely then the manifold cat has got weak. When cars are new , both cats are in optimal condition, when you take one of them off, for the initial few years , one cat can pass the MOT, when hot. As time goes the cat wears down and there needs to be a second cat to support it which there isn't.Sensor thing is highly unlikely. You could try replacing the 2 O2 sensors in the manifold but I don't think it will help. Sent from my SM-G781B using Tapatalk Share this post Link to post Share on other sites
Danny.BRZ 2 Report post Posted August 12, 2021 2 hours ago, BRZ-123 said: It is definitely then the manifold cat has got weak. When cars are new , both cats are in optimal condition, when you take one of them off, for the initial few years , one cat can pass the MOT, when hot. As time goes the cat wears down and there needs to be a second cat to support it which there isn't. Sensor thing is highly unlikely. You could try replacing the 2 O2 sensors in the manifold but I don't think it will help. Sent from my SM-G781B using Tapatalk Thanks for the advice mate it's a huge help. Would a sports cat help support the standard manifold to stop this from happening again? Share this post Link to post Share on other sites
BRZ-123 174 Report post Posted August 12, 2021 Thanks for the advice mate it's a huge help. Would a sports cat help support the standard manifold to stop this from happening again? Yes it would. Higher CEL the better (200 minimum).A cheap try could be a good 30 min blast before MOT to get your cat glowing and then straight in for testing.Alternatively people find friendly naughty MOT testers to help.Sent from my SM-G781B using Tapatalk Share this post Link to post Share on other sites
Danny.BRZ 2 Report post Posted August 12, 2021 1 hour ago, BRZ-123 said: Yes it would. Higher CEL the better (200 minimum). A cheap try could be a good 30 min blast before MOT to get your cat glowing and then straight in for testing. Alternatively people find friendly naughty MOT testers to help. Sent from my SM-G781B using Tapatalk Got a friend that works at Cobra exhausts that I might get in touch with for the Sports Cat. Tried the 30 min run and it didn't work haha Thanks for the help mate. Share this post Link to post Share on other sites
BRZ-123 174 Report post Posted August 12, 2021 13 minutes ago, Danny.BRZ said: Got a friend that works at Cobra exhausts that I might get in touch with for the Sports Cat. Tried the 30 min run and it didn't work haha Thanks for the help mate. Cobra have a ready made one. So ask him to get you a discount and be done with it, unless you want him to up the 200 cell to a 300 cell. Just make sure it mates to your Milltek but it should, i suppose. https://cobrasport.com/products/toyota-gt86-sports-de-cat-front-pipe-performance-exhaust?currency=GBP&variant=32119934419025&utm_medium=cpc&utm_source=google&utm_campaign=Google Shopping&gclid=CjwKCAjwjdOIBhA_EiwAHz8xmzm0TZrJEmOBoRjNH9TdP1ydZM0_szM4fntHru52eeRs1fz4OudwrBoCAHoQAvD_BwE This Toyota GT86 performance exhaust is made in 2.5"/63.5mm bore pipework and fits from the over pipe to the centre section. The sports cat exhaust option will still enable you to pass a UK MOT emissions test or police road side checks. The de-cat sports exhaust option is sold for motorsport and off road use only and will NOT be able to pass a UK MOT emissions test or police road side checks. Share this post Link to post Share on other sites
BigFrames 0 Report post Posted September 1, 2021 Id be interested to know if this does work as Ive just bought one with the Milltek system and the lack of the second cat is definitely a concern (not knowing any friendly MOT testers...!) Share this post Link to post Share on other sites
scbrz 10 Report post Posted March 19, 2023 On 8/11/2021 at 5:55 PM, Danny.BRZ said: I’ve got litchfields old brz it has a milltek primary cat back exhaust on it (secondary cat delete) and it seems to be having issues with emissions on the MOT. The car has passed every year since the exhaust was on, any reason why it would be over on the emissions? I had the same issue, it was the CAT in the manifold. Share this post Link to post Share on other sites