De-cat explained?

6th January 2010, 10:47

Hi,
I looking to fet a de-cat exhaust system for my car.
But, ive had very mixed opinions from people, some say it will 100% FAIL its MOT with a de-cat, some say it wont?

can anyone just explain this to me before i explode!!!

thanks a llot

sam

6th January 2010, 11:17

Will defiently fail. Your car needs a cat to pass an mot. Can always go a dodgy garage to get it done.

6th January 2010, 11:37

yeah mate, will fail mot with de-cat, so you just change it for the mot test, then swap them back when its passed, shimpless. lol.

6th January 2010, 12:10

Your car doesn't need a cat to pass an MOT, it needs to be below the limits of each test.

It won't definately fail. Some engines, that are running perfrect, or at least, almost, can, and do pass. Although it's very, very rare.

Basically, it's a 95% chance of failing without it.

6th January 2010, 12:20

Quote:

Originally Posted by titchster

Your car doesn't need a cat to pass an MOT, it needs to be below the limits of each test.

It won't definately fail. Some engines, that are running perfrect, or at least, almost, can, and do pass. Although it's very, very rare.

Basically, it's a 95% chance of failing without it.

you are 120% wrong.

the law states,that any car made over 1992 has to have a catalytic converter fitted.

wether itl pass or not is down to the mot garages dicretion,some will fail the car because it is failed on emisions or because simply its not fitted.
You run the risk also of being pulled over roadside by vosa and they will prosecute if you fail.
No modern engine would pass strict emission levels these days without a cat.
a cat hardly makes any diference to performance,bit like the thoery of a silenced exhaust makes less pwer then one that isnt silenced!

6th January 2010, 12:32

Well that's the first time i've ever heard that. I've heard of cars passing legitimate tests before with no cat, by being under the level, but i've never heard of a car failing just because it's not got a cat.

And after reading through this:
http://www.motuk.co.uk/manual_730.htm

There's no mention on there in the 'reason for rejection' section, that the car should fail for simply not having a cat either.

6th January 2010, 12:35

There's this thread:
http://www.saxperience.com/forum/sho...d.php?t=185206

Too.

In which a few people say they've passed legit without a cat.

6th January 2010, 12:39

i took mine to a garage, (dodgy) they said they put special oil at £15 a litre then run it till it was red hot, and it passed. i never beleived the oil story i think they used a different car for the emissions reading lol

6th January 2010, 12:41

Quote:

Originally Posted by titchster

Well that's the first time i've ever heard that. I've heard of cars passing legitimate tests before with no cat, by being under the level, but i've never heard of a car failing just because it's not got a cat.

And after reading through this:
http://www.motuk.co.uk/manual_730.htm

There's no mention on there in the 'reason for rejection' section, that the car should fail for simply not having a cat either.

done abit more research through various mot websites and i apologise,you are correct,as long as the car passes the emission,itl pass,cat or no cat.

although i doubt itl pass emissions without one.

6th January 2010, 12:42

Quote:

Originally Posted by snatcher47

i took mine to a garage, (dodgy) they said they put special oil at £15 a litre then run it till it was red hot, and it passed. i never beleived the oil story i think they used a different car for the emissions reading lol

special oil to lower emissions?i smell something there.

6th January 2010, 13:28

Quote:

Originally Posted by littleracer

special oil to lower emissions?i smell something there.

mite mean redex?? I still failed my last mot wit the cat in so the boy told me to chuck loads of redex in and bring the car back to be tested after it had been ragged...it passed, aparently it burns the redex not the fuel so passes