dave_t

iTrader: (1)

I have a 2003 WRX currently with a cat back and have a few exhaust questions that seems to be getting mixed opinions with regards to decatting & MOT.
The car has three cats. One in the up-pipe, a downpipe cat and a centre cat (sometimes referred to as a scrubber).

If i fully decat it will fail on emissions, plain & simple.

Will refitting the 'centre cat only' (4 easily accessible bolts) pass MOT emissions (even though i have a fully decated downpipe)? Scoobyworld do a performance package for this car which fully decats the downpipe but leaves the centre cat in place and state that it is MOT friendly?

I don't want the expense of changing a full downpipe at MOT (hence the question) as getting it wrong now will obviously cost me money later.

Assuming the above is correct the choices are:
1. Leave all cats in place, live with a cat back & remap
2. Remove the centre cat only (MOT friendly as downpipe cat in place?), get the same effect by gutting its internals & refitting?
3. Remove the centre cat & use a PPP downpipe (MOT friendly)
4. Decat the downpipe and leave the centre cat intact (MOT friendly?)
5. Say bugger it, decat the lot and come MOT refit the centre cat only.

From Scoobyworld:
We leave the factory 'catpipe' in place, and instead replace the original restrictive downpipe with our de-cat downpipe - this produces around 265 bhp (this setup has been tested on our UK car and passed the required MOT emissions tests well within the required limits)

See http://www.scoobyworld.co.uk/catalog...oducts_id=1504

Thanks in advance for any input.

joey_turbo

iTrader: (26)

I think 4 & 5 will be a no go. It'll be very difficult, if not impossible to pass with just the centre cat. Due to its location aswell, it will take a massive amount of heat to get it warmed up enough to do a good job.

gazney101

iTrader: (5)

My car passed a legit emissions test with only up pipe cat left in, it took 3 or 4 attempts but got there in the end, some mot stations will only give it 1 chance where as others will make sure it passes as long as the rest of the car is in order if you get my drift

Jacko4130

iTrader: (3)

Remove all cat's and then find a friendly mot tester.

Gear Head

iTrader: (2)

And risk the tester losing his licence and lively hood,all because some impreza nutter wants an extra 5bhp!

Fudgey

iTrader: (1)

Its up tot he MOT tester whether or not they want to pass a decatted car..

so ignore all the old women on here and decat the thing!

BLU

iTrader: (27)

The tester would argue that the cat was in place at the time of test

My classic only ran the down pipe cat and passed fine every time

Graz

No idea if they've tightened up the limits since I had mine (Classic) but it had a full de-cat system. Come MoT time I'd re-fit the centre pipe with cat, take it for a good blast to ignite it, turn up at the MoT station and get them to test it straight away (book a while-u-wait appointment).

Passed every time. Drove home and put the de-cat centre pipe back on the next day. Mind you it's all illegal and I drive a sensible car now with some really naff emissions control (DPF).

blackvenom

It doesn't take too long to swap a downpipe, I would suggest keeping the car thier to going for a ppp sports cat