My subaru 06 model sti has failed an MOT on emissions does anyone know which cat I need for it to pass the emission test.

 

first question would be do you have any cats in place and if so how many?

 

Both.

 

It's a straight through pipe from the turbo

 

Probably the one in the down pipe for emissions. Both for legalities. 2012 onwards the car requires all cats it was fitted at factory with to be present. To pass emissions you really need the one in the down pipe as it runs hotter and will burn emissions better.

 

Ok thanks. It's been re-mapped I'm hoping this wont effect the running of the car.

 

If you put the DP on then mot it then take it off that would be the best situation for your mot. But a catted down pipe + fitting if you can't do it yourself isn't at all cheap. If you run the car with the catted down pipe you'll need to have the map tweaked

 

I know a mate at garage that said they will put it on for an MOT then take it off for me. They don't charge me much they only charged me 120pound for a cambelt change and a new window motor fitted.

 

Was the engine / zorst hot when tested??? If sat about and cool prior it may have been why even with the cats present.

EDIT

I misread Don's post 'both' as the OP confirming both were present, doh

 

There weren't any cats present - he said he's got straight through exhaust

 

There are no cats present at all

 

Get a 200 cell DP then remap and leave in, as changing back and forth bit o a PITA, my 200 cell passes no probs

 

what about a sports cat DP ?
Best of both worlds.

 

Agreed - this is what I've done - next MOT due in June

 

So it's get some

#


OR get an MOT from this guy:




Oh, or a sports cat

 

Where abouts in Cumbria are you?

 

I'm in millom. If I got a sorts cat which cat which cat would it be?

 

you can usually specify 100 or 200 cell

 

Is the 200cell the first cat then?how much am I looking at?

 

The downpipe cat is literally that - a cat in the downpipe. There is then another cat which comes later on in the exhaust - approximately underneath the car at the level of the front seats.

Most people take the second cat out as it's an easy bolt on bolt off part. Removing this technically means the car will fail an MOT as it was meant to have one from new - but at least it's easy to put back on when needed.

The car should pass an mot on emissions with just the cat in the down pipe in place, even if it's a more free flowing sports cat. This is because it's almost at the very start of the exhaust and gets mega hot, hotter than required to burn exhaust emissions. Problem is, this part isn't as easy to replace at the drop of a hat. Bear in mind that this bit of pipework bolts onto the turbo, which sometimes causes issues in undoing the bolts - occasionally they need drilling out if they snap.

So best bet overall is to fit a sports catted downpipe then remap the car. It'll still flow freely but will be good for emissions, and chances are most testers won't be bothered about the second cat being missing as long as the car passes the smoke test

 

As an idea, on my hatch I paid £265 for the sports catted down pipe and other £100 for fitting but the fitting was a litte discounted on the basis that I was paying for a remap in the same session

 

I used to run a decat downpipe. It just wasn't worth it in the end - a sportscat is much less hassle.

 

I thought an 06 STi only had the one cat (DP) from standard. The part of the exhaust in the middle that looks like a cat is just a resonator. My RB320 (07 sti) only had a down pipe cat as standard. Is now has a japspeed 100 cell sport cat and passes the MOT. The sport cat does need to be quite hot to pass.

 

The down pipe consists of two parts each with a cat (items 17 &9)

 

My DP is on ebay 150 delivered 12k miles no problems at all, blob eye sports DP fits the hawkeye

 

Steve sti I will buy off u. What's ur name on eBay?

 

Main question here tho, dont you know any friendly mot testers that aint worried bout the emissions but look over the rest of the car

 

No unfortunately I dont

 

How does that work with the Prodrive Performance Pack cars, as far as I'm aware they've got a Sports Cat in the DP, and everything else is decatted. Wasn't PPP a dealership option?

 

ppp cars have cat in up pipe removed and standard cat in DP 600 cell