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De-catting for the stupid...





Okay, I know what a decat pipe is, but what is the law on de-catting your car? Everyone just puts the cat back on for MOTs, but what happens if youre spot-checked by the rozzers/pigs/little hitlers?

Do they just give you a VDRS form so you get 14 days to fix it, or is it possible that youd get a Prohibition Notice (!?!) as theyre pretty keen on these where emissions are concerned!
 


How the hell are they gonna know if you have a Cat on your car or not?

MOT means nothing anyway, just means at the time it was tested the car was road worthy, you may have cut the brake lines since but youd still be legal (and stupid...)
 

MaLicE

Honorary Member
ClioSport Club Member
  Lazy v8


um all they have to do is look under the car and will see summit quiet big missing.



not sure about radom checks though but i would like to know as im thinking of gettin a de cat pipe.



maLicE
 


How many coppers do you know that will:-

A; get on their hands and knees to look for a CAT under a (probably)low car and (most likely) in the dark

B; know what they are looking for?

C; give a to$$ when they can give you the same bit of paper that says (get your number plates (for example) changed and car re-tested.

Anyway, there we go. I have a de-cat (and lowered, 16s, filter and the like) and have never been stopped, let alone to check for CAT.

Get the pipe on there ASAP!
 
  Willy2


Mate

The only Rozzers you have to worry about are the TRAFPOLS, the ones with the white caps. Normal Police will not know a CAT from their ARS*, as for what you get, with the TRAFPOLS you are looking at a PG9(prohibition notice), these guys will definatly get on their hands and knees and look at every detail of your car. In London there are very few TRAFPOLS left. I have a very realiable source.(y)
 
  Willy2


I will contact my source, im sure they mentioned CO2 emmissions in the atmosphere. I will check and post some thing tomorrow.
 
  Lionel Richie


You dont actually have to have a CAT, as long as your car passes the emissions test you are fine (i think). I know someone that built a kit car with a 5.7 chevy V8 last year (no CATS) and it passed the emissions test!!!! So i guess that you can run without a cat.
 
  Willy2


better to be safe than sorry, my source states that IF your car fails the emmissions test then it wont pass the MOT. But the last posting states that he knew someone who didnt have cats on their car and the car still passed. I reckon you should get it De-catted and keep your original cat, when your MOT comes up send your car through and see what happens, if you do get stopped by the Rozzers and they do get funny with you all you have to do is tell them you still have the CAT and they should issue you a VDRS. It does seem like a lot of hassle but Im gonna get mine done soon and Im gonna keep my CAT in my garage just in case;)
 


the magnex de-cat pipe is designed to look like a cat!! just got a straight through pipe, presumably so if you do get caught on the side of the road the piggies cant tell the difference (without testing it)
 


Does this not mean tho (god forbid) if say... you write off your car for what ever reason, the insurance company give the car a look over.. class the de-cat as a mod.. see from you MOT it was road legal at time of test.. then decide not to pay out becuase you dont declare at time of fitting? :confused:
 


My exhaust is on way out, and quite fancy a new stainless one, preferably with de-CAT pipe. However my valver is a M plate and so is supposed to require one for MOT. Has anybody got a car, thats supposed to have a CAT, but it hass been replaced with a de-CAT through an MOT, without any shady agreements with tester. Has anybody got any emission figures for a de-CATTED valver, do they pass an emissions test.



Alex M
 
  BMW 320d Sport


Magnex are the only ones to my knowledge who make a cat-like decat pipe. Except its in tasty stainless.

The law is that the car must pass the emissions test at MOT time and its assumed that in the remaining year the emissions dont change significantly until the next test. Once you start modding the exhaust and taking the cat out you are probably going against the spirit of the law but not the letter of it. I run a decat all the time and dont even bother putting it back on for the MOT. Its easy to make clerical errors with emissions figures. If youre worried just keep your cat anyway and put it on if you ever get trouble. Which you wont.



The law is about emissions, not cats. As long as your emissions are ok, it doesnt matter how you achieve that. Regular servicing and looking after your engine help a lot.
 


again, there seems to be some confusion..

removing a cat will not guarantee a power increase !!!

the newer your car, the less chance of any gain and the more chance of a reduction.

on an old tech motor like a valver or williams, then maybe a slight increase.. but not on yer 172 without radically altering the induction too.. (ie - tbs or forced ind)

there ya go..
 


You wont get an F7 engine through an emisions test without a CAT. I mean without the clerical errors! It will fail tragically...

But kind of depends on who you know...
 


I wasnt thinking of a de-cat for performance reasons, I just got worried when I took some photos of my cat for mailto:M@thew">M@thew the other day and it came out as two rusty boxes under the car!!! I think its days are numbered... :( Obviously a de-cat will be much cheaper than a new twin-cat (I assume)...
 


hmm bugga, my car is going in tomorrow for a mot, and its got a decat om it, ive got the cat, but it wont be on for the mot, i was kinda hoping against hope that the emissions would be fine

wonder if its too cheeky to ask the garage to put the cat back on and retest :)
 
  williams and trophy


send it for the test n u get a free retest if it fails n u take it back within 7 days or summat at most garages
 


If It comes with one you need it for the MOT even if it could pass the emissions without & Not the other 364 days of the year the rozzers couldnt give a Feck been there with the problem myself & also a de-cat aint classed as a mod for insurance (well not with my insurance)
 


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