Wilky_Boy

Hi there,

I have a 04 reg WRX and have been considering getting a remap. After posting a question about this in the forum it would seem that I am better to de-cat the exhaust before getting the car mapped. I have a couple of questions about this and was wondering if anyone could help:

1)- How many 'cats' has my standard exhaust got ?

2)- How many can I remove and still pass the MOT ?

3)- Any recommendations for which de-cat pipes to use ?

4)- Are these DIY fit ? I'm relatively okay with a spanner and don't mind getting my hands dirty.

I already have a performance back box which I bought from Scooby World - should I be able to get pipework that will match the bore of my back box ?

Any comments or advice would be appreciated.

Cheers,

Wilky.

W1ndowLicker

The only way to pass the MOT if you De-cat it will be to find a 'friendly' MOT station !

NeilP1

Put the cat back on for 30min once a year

NeilP1

you have one cat in the down pipe

silent running

10 years ago you used to be able to buy bent tickets down the pub, nowadays the computerised DVLA-linked system is designed to make 'friendly' MOTs a thing of the past. Probably the only sensible way if you have to have a decat is to fit your cat, get through the MOT then change it back.

W1ndowLicker

These new computerised ones are all well and good but they cant tell when the guy puts the sensor in the exhaust and sometimes they just 'slip' and go in the wrong cars exhaust

chrisUK300

iTrader: (10)

or get a sports cat and dont have to faff about swapping cats over or finding friendly MOT stations

Semper

Sports cat aren't always the answer. A TTS member ended up putting his original STi exhaust back on for MOT.

Butty

iTrader: (2)

There are THREE cats on 01-05 WRXs.
Two in the turbo back system and one in the up-pipe just before the turbo.

Well proven sports cat system is one from an STi PPP and will allow 350 hp. Grab the sports cat downpipe, decat short section after downpipe and the std STi uppipe.

This lot should all cost £400 at most from a breakers or Ebay.

Nick

MrNoisy

iTrader: (28)

Yep - the man's right - 3 on a WRX; the STI is the one with none in the up-pipe.

If you're lucky you can pick the lot up for cheaper. I managed to get a Prodrive sports cat and decat pipe for £110, and an up pipe for £25. Keep your eyes on the wanted forums and ebay and see what you can find.

As other say the alternative is to either go decat and swap them MOT time, or find a "friendly" MOT station, which I'm sure your local Scooby club should be able to provide you with

silent running

LOL yes mistakes can happen

Personally I use a sports cat and don't have to worry about this problem at all. I think decat pipes etc are a thing of the last century, but that's just my opinion and many won't agree with me. I just don't think it'll be long before somehow they take out the human element so that 'friendly' stations don't exist any more. I mean what would it take - a traffic copper doing roadside emissions tests on all the fast cars or boy racers in one localised area, finding they mostly failed even though they were modern emissions-controlled cars, tracing back their MOT stations via the DVLA and bingo. That's a day's work, if they thought about it.

Ozzy_555

What if you just remove x1 cat (centre section) but leave downpipe cat alone would this be MOT Passable? I have a Classic Shape UK Model Turbo.


Cheers.

mbayley77

iTrader: (4)

That would give them a lead but an MOT only is valid at the point of issue and not there after....could anyone prove that the 30 minute test hadnt been carried out with a CAT in place as many people do? Only if caught red handed!

S3TH

iTrader: (2)

Go with what nick has suggested.

my car is an MY03 STi and made 330/312 with a remap, panel filter, prodrive sports cat, TSL de-res centre section and back box.

the RR operator commented he doesnt usually see any difference between full decat and sports cat kitted imprezas.

apalmer

iTrader: (8)

In Luxembourg all cars have their MOT'S performed by the same outfit, they go through a large warehouse type building and come out the otherside... Like the everlasting gobstopper No way to fool those guys.

Is spotted one of the hangers just outside the airport last time i was there and my colleague explained they way it works there! Germanic Efficiency...

@

PantsUK

iTrader: (1)

luxembourg has all sorts of funny car regs doesn't it ???

and it's fairly small !! (less than half a million people LOL)

apalmer

iTrader: (8)

Yeah, not just cars either, check out their redundancy packages. What a country...

PantsUK

iTrader: (1)

I have heard of some people making double catted centre pipes for popping on during MOT time!

NeilP1

i see only had one in my 93wrx/P1 and 05sti and all were taken out

silent running

Yes I see your point, but what I'm trying to get across is that OK there may be loopholes upon loopholes that can still be exploited, but the wind of change is not just here but it arrived several years ago. Emissions regimes are never going to loosen up and the only reason why so many Snetters and others are running around with decats for 364 days of the year is because as yet there isn't the political will to deal with it seriously. On a technical note, although the MOT is actually only considered in law a valid representation of the car's roadworthiness on the day it is issued, that does not give any driver licence to run an MOT-failure the rest of the year. The implication is that on any day of the year, your car should be able to pass the MOT and be roadworthy. Claiming that 'it passed emissions 6 months ago at Honest John's Garage, I don't know how that decat pipe got on there' is the most ridiculous excuse ever.

I don't want to rain on anyone's parade here, but just be careful is all I'm saying.

silent running

I have a classic with Graham Goode sports cat downpipe and straight through centre i.e. no second cat at all. It JUST passes once there's a bit of heat in the cat. I'd guess at operating temperature it would fly through, especially with a 'normal' cat, which would warm up better I guess.

Tazz Kill Er

My 98 classic just passed it's MOt with a TSL Sport Cat downpipe fitted and no middle cat, the mot tester did not treat it any different to any other car and was suitably impressed with the very low emmisions.

If you are caught with a car that has no cat when it should have one, isnt that classed as "not fit for road use" which means technically you have no insurance and they can seize the vehicle if you were caught in a roadside check.

silent running

Absolutely so ^^^ . Unless you're building an out and out big power track car, I just can't see what the point is of decatting. Even WRC cars have cats.