decat or not decat?
 

Hi all, I am looking at getting my car remapped in the new year, and I am currently getting some mods together beforehand in order to give the mapper a good chance, and so that I can hopefully do it once and be happy.

I am looking for around 300 to 320bhp hopefully, I already have a bigger top mount intercooler on, cosworth panel filter, TD05 16g ready to fit, 255lph walboro fuel pump, standard yellow injectors.

The car is a my00 turbo 2000.

My question is, I know I will have to get a decat pipe, but also want it to be MOT friendly, if I decat it, which section, as far as I can figure I have three Cats in there at the moment.

Thanks

on a classic you most likely only have 2 cats - one in the downpipe (main cat) and one underneath the car before the centre section.

Decat usually involves replacing both cats at the same time with a one piece longer pipe that still mates to the standard center section. Not sure about on the mainland but here in NI it would pass an MOT with no cats unless there's something wrong with the car.

Thanks bludgod, good to know, I was under the impression there was also a precat in the up pipe, but I maybe wrong, (I often am lol)

yes precat in the uppipe if you have a 2.0 WRX newage - 2.5's (wrx or STI)/ any STI or classics didnt have the uppipe cat.

that's great, thanks bludgod, still learning, everyday is a school day when it comes to these cars.

You'll struggle to get it to pass an MOT in the UK without any cat's. You can get away with just one cat (I've removed the center cat on my 1997 Turbo 2000 and just just have the downpipe cat and it's fine on the emissions at MOT time), but no cats will be almost impossible!

Any UK car from K-reg onwards (1st Aug 1992) is very unlikely to meet the emissions requirement without a working catalytic converter. The rule is slightly different for imports - they don't need the to meet the same emissions requirement until M-reg onwards (1st Aug 1994) so early Imprezas can get away without a cat, but UK ones, sadly not.

I think a lot of people who run full decats either swap a cat back in for the MOT, or have a 'friendly' MOT tester.

Or, you could opt for a sports cat downpipe and swap the centre section for a straight through pipe. I have this set up, the downpipe has a 100 cell sports cat, which has seen the car through the MOT for the last 7 yrs.

My 2002 & 2003 STI passed MOT with no cats, maybe its just down to the examiner...

matt - our NI tests are a joke compared to the mainland tests, sure hawks can go through here catless! Mainland test actually tests to make sure the cat is working as it should - ours is more like "is she shooting fuel out tha back like mate?" kinda test :)

lol, pity I can't just bring it over to NI for the test lol. Thanks for all the other advice, think i'm going to go down the route of keeping the downpipe CAT and decatting the centre section, and see how the map goes, hopefully be able to achieve my 300ish figure that way.

Ohhh, I see lol..

Yes as has been said your options are to removed the 2nd cat or go for sports cat, with 100 cell it will need warming up alot before it will pass, 200 cell barely need any warming up, but are more restrictive than 100 cell.