Holetownsilver

About to fit a decat exhaust but a little worried about insurance / omissions.

I assume the insurance issue is simple! However, how common are roadside omissions tests?

Will I be able to sleep at night?

GC8

Not with spelling like that I shouldn't think.

Holetownsilver

Spelling is fine, just the wrong word! Any advice re emissions!

mgcvk

Nocturnal emissions. Thats a sticky subject!

GC8

The advice Id offer would be to remove the up-pipe and down-pipe cats where fitted and replace the centre converter with a sports cat. Youll need to have you car re-mapped, no matter what people tell you..... Roadside emissions tests arent common but that said, I might get stopped tomorrow. Sports cat can be bought for about £200, I was reading about a suitable part at that price a few weeks ago but I cant remember where..... Seeing as a centre de-cat pipe costs approaching £100 its a bargain and your car will remain legal and wont need altering for each MOT test.

Simon

remfanuk

the impreza i am looking to buy has had the centre cat removed leaving the one on the downpipe still there. i am also curious about the emissions issue. if it will pass with the centre one removed, as i am assured it will, why did subaru put one on there originally?

GC8

Id expect the car to pass with only one catalytic converter, but youll need to ensure that it is up to temperature before the test. I assume that people remove the converters from their cars to improve performance, so I dont understand why they remove the second (centre) cat. The biggest gains come from removing the catalytic converters at the front of the car... Might it be because there's a large selection of massively over-priced centre cat replacement pipes available and people assume that that is because theyre beneficial.....(as opposed to being 'because theres a ****-load of profit to be made')?


Simon

Holetownsilver

Is there a CAT in the up-pipe?
My car is a MY05 WRX. If there is a CAT in the Up-pipe could my car pass with the Down-pipe and centre removed?

tarmac terror

iTrader: (2)

Regarding the emmissions for MOT you will be grand with no cats. My motor went through the NI MOT on Monday with a magnex decat downpipe & centre section.

Emmission levels for NI are covered in the Motor Vehicle (construction and use) regulations 1999. Carbon Monoxide < 3.5% and Hydrocarbons < 0.12% - these factors are the same for the UK according to our Department of Environment.


Even with no cats my readings were well below the threshold.

TT

lordharding

iTrader: (1)

what is everyones view on a remap after decatting ?
I have ran a decatted 2000 modle for 3 years now and no problems apart from waking up the neighbors !!


Is there any serious long term harm caused by no remap as i want to keep it a few years

GC8

I have never heard of an Impreza passing an emissions test without any catalytic converters. Whilst it may have happened, to generalise and suggest that cars will pass with all cats removed is rubbish; theyll struggle to get anywhere near to the required CO2 level... Im more familiar with Classics than New Age cars but I believe that your car will have 3 cats; the real benefit comes from removing the cats at the front of the car so why do you want to remove the centre one? You will still need to have your ECU re-mapped btw. This being ScoobyNet Im sure that someone will be along in a minute to tell me that they've removed the cats from their car and its fine, so Im wrong. Boost spiking is an issue but most people who remove the converters from their cars seem to be ignorant of it*.


Simon

*not directed at you lordharding; Ive been writing this for 20 minutes

lordharding

iTrader: (1)

never had a problem with my <local> garage ##

GC8

That's different though isn't it? Eh?

tarmac terror

iTrader: (2)

The NI MOT differs slightly from the mainland in that it is carried out by government employees not approved mechanics. The entire process is computer controlled and the results are recorded to rebut any appeal / complaint from the vehicle owner.

My car is a MY00 UK turbo. K&N 57i and full decat with original mapping on an AE802 ECU at the minute. My CO2 reading was 0.66% after 6 mile drive to the test facility and 10 minute idle on arrival. Exhaust gas analysis is carried out while they check headlamp aligment which is the first stage of the test.

I was told by four individuals not to bother with putting cats back on as the car would be grand. Their advice was spot on. From October they will be doing a visual check to ensure the physical presence of a cat and the test will factor Engine Temp, RPM at idle and ignition timing into the equation when testing emissions.

I would stand by my statement - but accept no liability should your motor fail!!!

TT