JamesArup Posted October 18, 2021 Share Posted October 18, 2021 (edited) Hey folks, Most of the posts I've seen vaguely related to this are 10+ years old, so I wanted to see if there was any new info out there. I am currently running a big single @ 620bhp or so, managed by a Syvecs S7i with a straight through (CW twin cat bypass pipes) 4" HKS Ti exhaust. It's coming up to that MOT time of year once again, where I have to beg, crawl and sweat to get the car though the emissions test (not to mention having no CATS is a no-no either way). Luckily, I do have a friendly MOT guy, but it's becoming such a chore each year, and I really don't want to keep putting the MOT guy in a stressful position, just because he loves my car, and respects it for what it is. Is anyone running 600+ bhp on a standard exhaust setup with both CATS in place, that actually passes the MOT emissions test without any fiddling around? Like, is there an option to replace my setup with something like a Blitz NUR Spec with both CATS, but still retain my power levels (I know it will need remapping etc). I was always under the impression that the restriction on the flow causes problems, but I am not so up-to-speed with modern systems and ECU's, and maybe it's less of an issue now? Hopefully that made some sense? Any feedback is much appreciated. Cheers, James Edited October 18, 2021 by JamesArup (see edit history) Quote Link to comment Share on other sites More sharing options...
erachter Posted October 18, 2021 Share Posted October 18, 2021 Quote Link to comment Share on other sites More sharing options...
erachter Posted October 18, 2021 Share Posted October 18, 2021 If you get a good catalityc converter (or 2) and a 4 inch exhaust you should have really minor power loss if anything at all. Quote Link to comment Share on other sites More sharing options...
Hissig Posted October 18, 2021 Share Posted October 18, 2021 Question is will you still pass with those sport cats? Quote Link to comment Share on other sites More sharing options...
erachter Posted October 18, 2021 Share Posted October 18, 2021 11 minutes ago, Hissig said: Question is will you still pass with those sport cats? On a "MOT test" tune you should pass Quote Link to comment Share on other sites More sharing options...
JamesArup Posted October 18, 2021 Author Share Posted October 18, 2021 Ahh great. Thanks for the video, very informative. The HKS Ti is a good exhaust (if a little loud), so if I can just drop a CAT or two back into that, that would be ideal... if I can find one. Although I think a guy literally 5 mins down the road from me makes CAT's for McLaren's (as the factory is very close), so probably worth having a word with him to see what he can do! And yes, will make sure there's an MOT setting in the ECU for this time of year I'll keep investigating and see what comes up! Cheers! Quote Link to comment Share on other sites More sharing options...
Noz Posted October 18, 2021 Share Posted October 18, 2021 12 minutes ago, JamesArup said: Ahh great. Thanks for the video, very informative. The HKS Ti is a good exhaust (if a little loud), so if I can just drop a CAT or two back into that, that would be ideal... if I can find one. Although I think a guy literally 5 mins down the road from me makes CAT's for McLaren's (as the factory is very close), so probably worth having a word with him to see what he can do! And yes, will make sure there's an MOT setting in the ECU for this time of year I'll keep investigating and see what comes up! Cheers! Definitely share any information or opportunities for a group buy for 4" or 4.5" cats. I know realstreet had a 1000whp with a twin cat setup that sounded sensible. This is the way forward. Would rather somewhere reputable than some eBay 4" and then still have emission problems. Quote Link to comment Share on other sites More sharing options...
JamesArup Posted October 18, 2021 Author Share Posted October 18, 2021 Will do! I'm not in the UK at the moment, but I can get my Brother on the case, he basically lives opposite this guy! I'll let everyone know if anything useful comes out of it .... 1 Quote Link to comment Share on other sites More sharing options...
Frank Bullitt Posted October 18, 2021 Share Posted October 18, 2021 Having an MOT emission setting on the ECU is the easiest option providing your mapper sets it up correctly. Quote Link to comment Share on other sites More sharing options...
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