Decat pipe fails MOT, no supprise, advise onthe way forward?

norad97 · Mar 11, 2019

Hi all,
My car had pre-mot emissions check and it failed, I was not supprised as the cat was removed and decat pipe was fitted.
I have the cat from the previous owner and getting refitted, but then I thought I have a MRC stage 2 remap,
what affect will this have? I spoke to MRC and want to charge me about £500.00 to remap the car again
with a disscount.
So I thought what about a sports cat? I have a Milltek exhaust system but cannot find a Milltek sports cat
for B7 Quattro.
Any advise or If you have gone though this yourself, like to hear from you.

Flowrider99 · Mar 11, 2019

Do you have no CAT's at all?

norad97 · Mar 11, 2019

No Cat fitted to the car just decat pipe, I have the original OEM cat in a box.

Sidrick · Mar 11, 2019

The obvious one would be the 034 Motorsport item.

norad97 · Mar 11, 2019

I was looking at 034 Motorsport Cat, but does it pass the UK mot ? I read a disclaimer on a USA site that it fails some US states?

Charlie Farley · Mar 11, 2019

Hi Richard,
I have the 034 and it will pass the MOT, well mine did.
sometimes your friendly MOT guys will have to run the engine up a bit to get it nice and hot to get it through , sometimes not, mine went straight through.
Your best bet is to either get a sports cat as above or put a normal oem cat on for the mot, a lot of messing around but that's probably the only two options really.
If you need an oem cat I still have mine you can borrow to get you through if that's of any use.
034 HFC's are silly money new these days and used ones are very short on the ground indeed and also a tad costly.

cheers
rob

Sam1989 · Mar 11, 2019

The 200 cell ones should easily pass. People that are using them have said they always pass. Have seen people putting 100 cell ones and just say they had to make sure they got everything really hot before the test.
Some American states seem pretty crazy, California is really strict. I read posts on audizine saying if they had removed the pre-cat they would fail emissions testing

norad97 · Mar 11, 2019

Hi Rob, thanks for the offer, I have been trying to find 034 Motorsport cat, contacted Awesome GTI but it will not be delivered until mid April.
So looks like I will have to put the OEM cat back on for now, (I did get the OEM cat from the seller) unless there is on in the UK.

Sygh2k · Mar 11, 2019

Try these
https://progressiveparts.com/?make=...ory=10946&post_type=product&action=vpf-search

Charlie Farley · Mar 11, 2019

They have certainly shot up in price.....

norad97 · Mar 11, 2019

Yes, but it states 2 weeks?

Sygh2k · Mar 11, 2019

Ah thought it said in stock, my bad

antwan64og · Mar 11, 2019

Just find a modification friendly garage and pay an extra £20 for a special MOT..... hypothetically someone might do that :whistle2:

BakPak · Mar 12, 2019

£20 poking out the ashtray. Lol.
Seriously though a buddy of mine has a b5 S4 decat and the mot costs him £100. You'll find the tuning garages are going to be more sympathetic, think about it they come across this every day.

Charlie Farley · Mar 12, 2019

I have a friendly garage but they wont rig the emission test for anyone, wether there is a "bung"involved or not.
They wont risk it full stop, and don't forget the emission results do get printed out so if they are modified to get a car passd that's a whole different ball game.
Sports cat are passable ,but no cat at all will never get passed an MOT legally, take your pick.

norad97 · Mar 12, 2019

Hi, thanks for your replies, I thought about taking back to the last MOT garage and see if they pass it, the problem is that if I argue with them they might
go out of there way find another way to fail the car.
I have decided I want a 034 Motorsport Sports Cat, but I cannot get one until mid April, so it looks like all I can do is put the OEM cat back on for test,
then get it removed again when I get Sports Cat. MOT expires 24 March.
I want a Sports Cat Now !!!!

45bvtc · Mar 12, 2019

Sad to say but January 2012 rules are NOW being applied:

Charlie Farley · Mar 12, 2019

exactly, if i had a cat to start with it will still need it, wether its a sports cat or oem, a de-cat pipe will fail straight away.

BakPak · Mar 13, 2019

I'm told the power gain in removing a cat is quite minimal so why bother?

Terminator x · Mar 13, 2019

BakPak said:
I'm told the power gain in removing a cat is quite minimal so why bother?

Noise? On the RS3 it made a big difference.

TX.

Sent from my BBB100-2 using Tapatalk

Charlie Farley · Mar 13, 2019

BakPak said:
I'm told the power gain in removing a cat is quite minimal so why bother?

come and try mine, the 034 HFC with a large bore down pipe does make a big improvement, even with a standard system, well worth doing .

45bvtc · Mar 13, 2019

BakPak said:
I'm told the power gain in removing a cat is quite minimal so why bother?

Noise and throttle-response. On the 8P RS3 there IS a difference to be heard and felt driving with secondary cat by-pass pipes. But you're right in that there's little power gain, non to be felt anyway.

Neither are the emissions much effective: on my own 8P RS3 CO emissions WITH secondary cats was 0.01% and 0.02% without, and the pass limit is 0.20%. But I do run with secondary cat by-pass pipes (noise and throttle-response) and will continue to do so - and have my car MOT'd by them that I know will.

My Milltek labels fell off a long time ago:

Charlie Farley · Mar 13, 2019

terminator x said:
Noise? On the RS3 it made a big difference.

TX.

Sent from my BBB100-2 using Tapatalk

yep , abit louder but way more angry :thumbs up:

mine just burbles away until you open the taps and then it sounds very angry....which I like , the wife says she can here me coming down the road with this growling tone.
I think she's pulling my leg sometimes :haha:

Sidrick · Mar 13, 2019

Which down pipe did you go for, Rob?

Charlie Farley · Mar 13, 2019

had a custom one made up to suit.

Rob Avant · Mar 14, 2019

Another vote for the 034 HFC... As JustRob said, just get your tester to warm it up first

norad97 · Mar 15, 2019

Hi, I have ordered one from Awsome GTI, its normaly 3 weeks delivery as they have shipment once a month,
was told yesterday the shippent arriving today has got a Sportscat in, and I have bought and paid yesterday, phoned to day and confirmed I will get it by Wednesday, lets hope it all goes to plan!!!

Charlie Farley · Mar 15, 2019

Well that's a bonus Richard, I was going to say I'd sell you mine as i'm looking at a new complete system , but seems you are sorted now.
good luck chap, make sure you get that second after cat lambda sensor spacer, you'll need it.

rob

norad97 · Mar 15, 2019

I think with a stage 2 remap they disable the system, so I beleive, as i am not geting any lights with the decat pipe, but if im wrong please advise.
Rob, why did you need a new down pipe?

Charlie Farley · Mar 15, 2019

Evening Richard, I have the stock main system with custom 100mm quad tips , but the step down in tube diameter from the 034 outlet onto the oem down pipe is a lot smaller, quite a step in fact.
As I wanted to retain the stock main part of the system I had a custom downpipe fabricated to smooth out the transition form the large 034 outlet into the oem system, effectively a tapered down pipe.
Works very well, the post cat sensor is moved out of the gase flow by using a spacer so it doesn't throw up a MIL light etc.
I was thinking this week about changing the whole lot for a new miltek system with cat , but seems they don't do that setup anymore for our old buses so will just stick with what I have, well it works great so why mess with it cam eto mind.

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