mestonian

I'm looking for some help, basically i'm looking at a Blob STI or Hawk STI (not sure if they're different) but i've heard they have multiple cats.

How many do they have? Can you safely remove one and still pass MOT, if so which one? Is going full decat worth having to change it back every 12 months or would a race cat suffice, etc.

Just trying to clear up in my head options.

Thanks

AzzDSM

Downpipe cat
front cat
centre cat

uppipe cat in the wrx

I believe it will pass just having the downpipe cat but il stand to be corrected

mestonian

Jesus, more cats than these guys http://www.cats.org.uk/

The Pink Ninja

iTrader: (23)

Sti just has 2 cats, downpipe and just after that prior to the centre section of the exhaust

mestonian

Perfect thanks, i think some people see the resonator on the centre section and think that's a 3rd.

AS Performance

iTrader: (4)

the newage STi's only use 2x cats, basically you have a two piece downpipe that contains a primary and secondary cat..............

after that its simply a resonated centre section and back box

none of the STi's ever had the up-pipe "pre-cat" fitted (neither did 2.5 WRX's)
the only models this ever applied to was 2.0 WRX 2001-2005

rogos

My scoob is an 05 sti type uk with ppp, it has just one cat in the prodrive downpipe the rest is straight through and it passes genuine emissions tests with ease.

The Pink Ninja

iTrader: (23)

That's because it's a sportscat that's fitted not a standard cat ��

rogos

Well obviously we know that. The op asked if a race cat would suffice and as it happens yes it would, so i answered that part of the question.

scoobyJim2

I have prodrive downpipe race cat and no others on my 04 blob and it squeezes through mot emissions.
Apparently all you need to refit come mot time if you have a straight through exhaust,is the cat that goes after downpipe,which is much easier than having to change downpipe

joshnosh

iTrader: (1)

this is basicly what i was going to say aswell.

STI8Dave

I run a 100 cell sportscat downpipe on my blob sti and the rest is a straight through 3" system. It sails through MOT's and is the closest you'll get to decat if you want to stay legal.