de-cat help !!!

[b47to]

right a m8 of mine has offered to de-cat my car he said he will only replace the middle 1 !

so the question is will it pass the M.O.T

he said it will as there is 2 cats and you only need 1 ??

also what is it that i gain from doing this apart from it sounding evil

he says to custom make it he needs a middle section of the micra exhaust cat back with flange and he will make a custom flange on other end

 

[joesouthgate]

some people have failed without a cat irrc some have passed! depends on the tester and the car. i would keep original cat to put back on if it does fail.

 

[frank]

b47to

the easiest way is to extend the middle pipe and bolt the flanges together (there,s a pic on my blog)
i think there is a small gain, and the 1st cat is the important one for emisions

 

[joesouthgate]

frank
Has yours gone through an MOT decatted?

 

[frank]

moddedmicra

not yet :laugh: (due july iirc)

 

[ollie240585]

I passed mine with a standard manifold with Primary cat, along with a Janspeed De-Cat (secondary cat)

Even told the MOT guy it was a de-cat, it flew through the emissions test, everything was well below what it needed to be!!!

 

[joesouthgate]

i suppose it depends alot on the ware of the engine etc. service intervals and what condition the lambda sensors in.

 

[ollie240585]

If you remove the primary CAT you are looking at a 50/50 chance of MOT failure, secondary cat does pretty much bog all and just removing the secondary cat you should be fine!!

As said above, also things like your lambda and MAF can affect your MOT emissions figures

Performance wise you wont notice a thing, it'll barely show on a rolling road TBH

 

[jim_bling]

mine passed with janspeed manifold on with 2nd cat on not sure how but it did so just depend really

 

[Retepetsir]

Mine passed with primary cat removed (Janspeed) and secondary one in place. You just need to get the cat nice and hot and also make them hold the rev's at the higher end of the allowable scale, i.e. ~3000rpm instead of 2000rpm. Mine failed miserably when held at 1600rpm, but passed easily at 3000rpm as it leans out!

 

[b47to]

so is the cat im talking about takeing out the secondary cat ??

 

[Robert]

Yup, the primary is in the manifold.

 

[b47to]

so which is the main 1 that is guaranteed to fail mot

cheers for your help frank but if i do that i wont bable to re attach my cat back for mot