MK4 Ibiza FR TDI De-Cat

Mick288

Active Member
Aug 3, 2009
434
1
Lisburn NI
Ive been told by a few people that because its a new car with a cat fitted as standard, the cat must be fitted to pass the MOT...
Any truth in that?

Mick
 

knackerdecobre

Guest
Ive been told by a few people that because its a new car with a cat fitted as standard, the cat must be fitted to pass the MOT...
Any truth in that?

Mick

Sorry to sound harsh, but have you read this topic at all?
 

Mick288

Active Member
Aug 3, 2009
434
1
Lisburn NI
Of course i have, its just ive heard this from quite a few people and i dont fancy failing my next mot for not having a cat fitted... Ive heard some places say you need to have one fitted, but if you slip them a tenner and say its 'in the boot' or whatever, theyll give you a pass...
 

Aimez

Active Member
I want this done but thouhgt I had to buy a decat? I already have Milltek cat back and want to finish it off. Whatis the point/plus side in buying an aftermarket one instead of just getting an exhaust place to cut the cat out?
 

Arnoldo

Diesel Fr :D
Mar 22, 2009
200
0
N.Ireland
it does put more pressure on the turbo due to the release in back pressure. But only in theroy to be honest, its more mechanical engineers that will tell you that as appose to mechanics. It will be very sooty though when booted and reasonably loud.

Diesels only get a standing emisions test and not a under load test so can get away with a decat.

I knew my mechanic was right lol.
 

FR8ZER

PD150 FR+
Feb 8, 2010
58
0
East Ayrshire
cant see how removing the pressure would strain or hinder it.

Is it easier 2 open a door with someone leaning against the way ur opening it... or no one there at all. The door would open from point a to b the same wae in both instances, but with no-one its easier and better for its purpose. As does the turbo spinning up, with no cat there, theres nothing to strain it doing its job.

either way, the car drives alot nicer now, well worth the mod at zero cost
 

knight85

Money spending clown
Dec 30, 2008
2,222
0
South East
for the 4 or 5th time...you dont need a cat for a DERV MOT TEST....as no emission test just visable smoke test.

Also i have found that the decat and downpipe has given me a bit more boost as was running around 23 psi with just stage 1 remap, panel filter, milltek cat-back and pd160 intake but now im bit over 24 psi with the milltek decat/downpipe
 

krussel

Active Member
Oct 31, 2008
1,713
2
Hertforshire
I ve read a bit on de-cating on the Jaguar X type forum. What they do is remove the cat and simply knock the inners out then put the shell back so it looks standard. I haven’t climbed under mine but from what I see from the pictures this could be tricky on the Ibiza without cutting the pipe? :shrug:
 

knackerdecobre

Guest
You don't need a cat for a diesel for the UK MOT test!

Removing the cat may change back pressure a bit, but not enough to worry about! There are plenty of people running with no cat's for years and have no problems at all!
 
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