decat consequence advice please
Discussion
I was considering removing the cats on my n54 335i then at the last minute decided not to on the grounds of mot friendliness so to speak. I've been informed that the secondary cats are enough to scrape it through an mot, but what I want to know is, how much is it scraping through? What I want to know is that is it cross your fingers time every mot if you haven't got a 'flexible/friendly' mot inspector?? I'm still temped as this car will probably be my last fetish for fast motors before in a few years time I decide to by something sensible. I just wanted to squeeze as much as possible out the car without spending thousands on big turbos etc. current mods are intercooler, charge pipe and inlet pipes and its quite fast now as I'm running a JB4 on auto tune, which will be gone when I'm done in favour of a custom remap. Thanks for any opinions!!
Oh right, not worth it then, I was led to believe it was quite a noticeable gain but no it wouldn't be a diy job however I can get that sort of thing done cheaply, my mechanic recons he can remove the cats from my existing downpours, cheaper than buying decat sections but as were are talking cross fingers time every mot probably then I'll probably hang on to them
Sorry sounds a silly question but if the car is still passable with the secondary cats in place and on a visual inspection of the exhausts which would show the down pipes in tact, I'm convinced they won't strip the car down to find out surely? Any way I will probably keep hold of them if there is too much doubt
From the horse's mouth;
https://www.gov.uk/government/publications/modifyi...
It's not about MOT pass / fail per se;
"For example, removing a catalytic converter or diesel particulate filter will almost certainly result in a vehicle’s emissions exceeding type approval limits and make the vehicle illegal to drive on the road."
https://www.gov.uk/government/publications/modifyi...
It's not about MOT pass / fail per se;
"For example, removing a catalytic converter or diesel particulate filter will almost certainly result in a vehicle’s emissions exceeding type approval limits and make the vehicle illegal to drive on the road."
JonChalk said:
From the horse's mouth;
https://www.gov.uk/government/publications/modifyi...
It's not about MOT pass / fail per se;
"For example, removing a catalytic converter or diesel particulate filter will almost certainly result in a vehicle’s emissions exceeding type approval limits and make the vehicle illegal to drive on the road."
But illedgedly an n54 can pass on just the secondary cats, that was the point to the thread really was how much it was a gamblehttps://www.gov.uk/government/publications/modifyi...
It's not about MOT pass / fail per se;
"For example, removing a catalytic converter or diesel particulate filter will almost certainly result in a vehicle’s emissions exceeding type approval limits and make the vehicle illegal to drive on the road."
Andy70 said:
Sorry sounds a silly question but if the car is still passable with the secondary cats in place and on a visual inspection of the exhausts which would show the down pipes in tact, I'm convinced they won't strip the car down to find out surely? Any way I will probably keep hold of them if there is too much doubt
But in your OP you said you were going to have the first cats removed...… Now you aren't????Ah good old rumour! I was bitten by that when I was a lad; decatted one of my cars that according to a forum would sail through an MOT minus the cat. It didn't and even messing with the mapping I couldn't get the damn thing to pass it's MOT. The cat had to go back on, which fouled the front ARB and rattled like hell. In the end the race manifold I had on said car got sold and it went back towards stock. Put simply, it's not worth the hassle, or the potential trouble should VOSA pull you over for a check/if you bin it and Mr Insurance assessor is looking at ways not to pay out.
Lots of people think an n54 should pass the mot on the secondary cats alone, hence why it seems a popular mod by tuners to remove the primary cats but as it's debatable I won't bother. I was intending to remove the cats out of the original down pipes then replace them cat free, so to an inspection the original units are in place. That option was suggested by my mechanic and another that done some work on the car, both saying it's cheaper to do that than buy catless down pipes that look different, hence my comment regarding how I'd get caught out if the down pipes are seemingly in place and the car scraping the emmisions on the secondary cats alone.
Tyre Smoke said:
Pica-Pica said:
Previous threads on here from MOT seminars, show a possible fine of up to £3000.
Rubbish. The tester is not aloowed to dismantle anything. If the exhaust is intact, then it's either a pass or a fail. The tester cannot know why it's either.Pica-Pica said:
Tyre Smoke said:
Pica-Pica said:
Previous threads on here from MOT seminars, show a possible fine of up to £3000.
Rubbish. The tester is not aloowed to dismantle anything. If the exhaust is intact, then it's either a pass or a fail. The tester cannot know why it's either.Andy70 said:
HM-2 said:
Plenty of high-flow options for the N54 335i which will give most of the performance benefits of a decat without the drawbacks.
Cool any suggestions? ThanksThere's not really a lot of point doing so unless you're already running other modifications, though.
With your specification I would say the value is questionable; don't think you'd likely gain that much either way.
Gassing Station | BMW General | Top of Page | What's New | My Stuff