JayTee

Car's failed MOT on emissions due to de-cat.

Are they're any additives which can be added to Petrol??

Or have you got any ideas to get it throught it's MOT??

Cider boy

Is it a UK car or JDM import?? This makes a difference to what emissions are alowed. If it's a UK car then the quickest way round a de-cat is to find a friendly MOT station in your area!

Matt

scooby-tc

iTrader: (2)

Just put the standard catted downpipe on for the MOT then swap it back once its through.I had the very same problem with mine and it sailed through with cat on.Now its back to how it should be

CEL

iTrader: (1)

Simple as that TC?

Cost me nearly £100 in labour alone to have mine swapped last time. The friendly MOT station is your best bet

scooby-tc

iTrader: (2)

Easy job to change downpipe i can do it in 35 mins now

ozzy

Forget the downpipe, stick a catted centre on it. If the station is friendly, the don't even need to fit it. Just stick it on the end of the tailpipe and put the probe in the other end of the centre.

That should be enough to pass it.

Stefan

P.S. It'll never pass with a full decat.

tmo

Just borrow a cat'd centre section and bung that on, 15 min job if that !

JayTee

It's a jap import 1999 V-reg STI 5. No original downpipe and cat got damaged and still got centre cat in place and original backbox!

Dark Blue Mark

There isnt a cat in the centre, thats just a resonator.

Where are you based? There are a few people who have developed a twin cat centre they would lend you.

Taking the downpipe is never a 35 min job - it takes at least an hour and a half, and thats if the heat shield are cut, you know what you're doing, you have ramps, and none of the bolts are seized. I wouldnt reccomend changing it.

Incidentally, it sounds like you haven't had the car long - if its a V5 decatted, I hope you've had it remapped? It will detonate if you dont use Optimax and booster as required. I would highly reccomed a tek remap, or at least an uprated fuel pump and reg on a decat.

MB

JayTee

Already detted it and had a new STI engine put in and had it re-mapped supposedely to a P1. Is there anything you can put in the fuel for it?

Thanks for your help

Based in sheffield

Dark Blue Mark

Flaminsmart, yeah - ok

There's nothing you can put in the fuel to mask the Co2?! You simply need to replace the cat. Centre one preferably. Dont know anyone in Sheffied, but id ask for help in the "Northern" section.

MB

JayTee

Ok, thanks for your help anyway

Scooby_Dan.

Take it to Scoobyclinic

red wrex

I though octane booster was supposed to make your car a little "cleaner"

vindaloo

Try 'phoning your friendly performance exhaust centre. Maybe they'll sell or lend you a cat. I assume there's a lambda still attached to the downpipe rather than a fix/bodge.

Even though it's an import, it's a late model, so it's unlikely to pass without a cat. of some sort.

BTW: I thought cats produced MORE CO2 than without. They're supposed to control oxides of Nitrogen (NOx) Carbon Monoxide (CO) and incompletely burnt fuel (HCs)... As they convert CO to CO2, more CO2 is released. It's been a while, so I could be wrong.

J.

David Lock

J, Correct it's CO and HC levels along with Lambda they are looking for. The difficulty without a 'cat is CO level at tickover particularly. DL

glen4

I'd get flaminsmart to do it, drop him a tenner and I'm sure he'd be happy, with about £20 an hour

pblakeway

ive got a 'spare' centre section from a uk car that im happy to lend out
im near wakefield if thats any use ?

Dark Blue Mark

Glen, yeah, you must be slow, ill get him to do mine next time

MB

andypugh2000

My first downpipe change took about 90 mins inc fitting the whole system, i done it a few weeks ago in half that time

Dark Blue Mark

Im sure you did before you woke up and had your cornflakes

If you can take mine off and refit it in 30 mins, you can have my car. Ill even put some neverseez on to help you.

Point is, the guy posting has obviously never done one, so probably not best to advise him to do so if he's in a rush.

MB

stevie boy

first time me (engineer) + mate (who's a mechanic) changed the full exhaust on a 4 poster it took around 5 hours. 3 or 4 of the 5 turbo studs/bolts were siezed, or would turn, but not move down the threads. chop up the heat sheid to fit, find a bolt for the second lamba boss (that i didn't need), that was at least a close fit then weld round to seal it. now takes about an hour taking it steady on a set of small car ramps which is actually easier than on a 4 poster.

i know of 1 scoob that passed with a full decat and a week later mine failed just, so put the standard exhaust back on and still failed. turns out the maf was failing (MY00 induction kit) test passed, then the lamba failed about 2 weeks later.

i always oil the turbo bolts the night before or at least half an hour before attempting to remove them and never had any probs since

stevie

glen4

, yeah righto

StickyMicky

sum have cats in the center

you say its never a 35min job, and then say its possible to do it in 30 mins??

i could have mine off in 30 mins easy

scoobynutta555

lol Tc and Flam.

Dark Blue Mark

Clueless? You've not been on here long have you? For someone who spends most of their time giving advice in the technical forum, I probably know a bit more than you think

And by your timings, you clearly can't add up properly, as the whole job would be 22 minutes. Well agree to disagree though

Sticky - UK cars have a centre cat. STi4s and 5's dont. And when did I say it was possible in 30?

MB