Mk 7.5 1.5 TSI Exhaust CAT question, undo decat

[Aaron1875]

i want to make my vehicle road compliant, previous owner had a decat and mostly straight piped through,

I’m wanting to reinstall a sports cat but want to be sure of the original location of the OEM standard CAT ?
How many CAT’s do these cars have ? It’s the 1.5 TSI DACA engine.

I’m unsure whether there was another CAT after the turbo downpipe GPF and flexi joint ?
I’ve tried Googling and not many pics come up of the OEM setup. Can someone confirm the 2nd pic attached below is the original OEM setup ? and am I right in assuming the CAT is the bulky horizontal piece situated after the downpipe flex joint and mounting bracket ? because this is defo missing on mine.
In the 2nd pic attached of my vehicle you can see that during my ownership I have had a small straight Power flow resonator installed, to quieten the drone and excessive noise. The original larger silencer would have been located slightly further back. Looking at 2nd pic, is there sufficient space to weld a cat back in between front red mounting bracket and the 2nd metal round joint bracket ? Is it an issue if the centre resonator is situated only a short distance from the CAT ?

pic 1 is Google pic of supposed OEM setup and
pic 2 is current setup on mine.

 

[golfdave]

From the ERWIN manual for your engine code:-
One cat next to the turbo & one cat after the flexi section & under the gearstick area...like most EA211 engines..

 

[golfdave]

Here's the silencers:-

 

[Aaron1875]

Thanks ! for this Dave, your a wealth of knowledge !

The 2nd CAT has defo been removed then.
and resonator/part no 2 was also removed but I had a smaller resonator put in when I bought the car , you can see it in the pic (but I’m not happy with the install, welds and wrong apertures, so that’s gonna be replaced too),
I have part 5 though yay !!!!
but part no 6, rear box silencer has been removed and I have stainless Y pipes to stainless polished quad tails.
Now the question is which Company do I choose for the weld in CAT and centre resonator ? Milltek-expensive, Magnaflow ? Power flow ? or Piper ? and also need to determine what aperture size my stock pipes are so I can order the correct CAT and centre box size to marry up to ?!!!

 

[golfdave]

Another company who make cats & race (200 cell) cats is BM catalysts.

Manufacturer of Catalysts, DPFs & Front Pipes (bmcatalysts.co.uk)


...another company who makes good stuff is Supersprint..

performance exhaust systems, performance racing exhaust systems, sport exhaust systems, Home UK (supersprint.com)

or Remus

Remus Exhausts - The World Leader in Sports Exhausts (remus-exhaust.com)

However as its a 1.5lt EVO engine there is not much for it......back to OEM methinks..

 

[Aaron1875]

That’s correct Dave not much at all, I took it a reputable custom exhaust place today and he says looking at the pictures of the downpipe, the top Cylinder nearest to turbo is the CAT and the second bulge further along the downpipe is the GPF. He says because the emissions are stupendously high that CAT has definitely been gutted. So I don’t have a CAT we know the GPF has been removed.
This leaves me in a quandary ? He suggests I find another complete downpipe from breakers,
so my query Dave is could you please check ERWIN whether the 150 TSI one will be compatible ? I have found a few golf 7.5 and mk8 with similar 1.5 TSI engines breaking but they’re rated at 150 DADA engine code wheras mine is a DACA 128/130 originally.

thanks in advance

ps if your ever in Brum I’m happy to treat you to a Pan Asian Curry or whatever you fancy !

 

[golfdave]

That’s correct Dave not much at all, I took it a reputable custom exhaust place today and he says looking at the pictures of the downpipe, the top Cylinder nearest to turbo is the CAT and the second bulge further along the downpipe is the GPF. He says because the emissions are stupendously high that CAT has definitely been gutted. So I don’t have a CAT we know the GPF has been removed.
This leaves me in a quandary ? He suggests I find another complete downpipe from breakers,
so my query Dave is could you please check ERWIN whether the 150 TSI one will be compatible ? I have found a few golf 7.5 and mk8 with similar 1.5 TSI engines breaking but they’re rated at 150 DADA engine code wheras mine is a DACA 128/130 originally.

thanks in advance

ps if your ever in Brum I’m happy to treat you to a Pan Asian Curry or whatever you fancy !

How long since you bought the car??..basically any MOT cert has been rigged & the car is NOT road legal....should be able to sue the dealer...

As for ERWIN, I don't have a current subscription....& the info I have is all the PDF workbook downloads...for parts its ETKA...& I just use the free one which is upto 2016yr...so misses out your cars part numbers.

You might have to ask nicely at a VW dealer parts dept. for the part number.....I had a look at the older 1.4lt engine parts & all the 122/125 & 140/150PS for EN grade 95ron petrol (basically UK/Europe cars) all share the same downpipe...

exhaust pipe with catalyst - Golf/Variant/4Motion(GOLF) [EUROPA 2016 year] (7zap.com)

Part 1, ending 502-X

The other two versions are for other fuels like bioethanol etc...so in theory the 150PS version should fit your lower PS version....but please double check.

 

[Aaron1875]

Thanks will bother the dealers lol !
I bought it private, not had it long, but was aware it had decat but didn’t think the top may have been gutted, to be fair it may not be, I never had it on ramps when I visited the exhaust place, just spoke to the guy, he reckoned top ones a CAT abd second one is a GPF ?, The last time it was in the air I had a look at the top cat but I couldn’t see properly whether there were any weld marks from where it may have been gutted and re-welded. It didn’t look as though it did.
Ideally if I could get the diameter of my downpipe then where the 2nd CAT has been totally removed and straight piped, I will opt for a quality 200 cell sports CAT to be welded back in, surely that should get me back within legal tolerance limits and reduce pungent smell.

 

[golfdave]

Thanks will bother the dealers lol !
I bought it private, not had it long, but was aware it had decat but didn’t think the top may have been gutted, to be fair it may not be, I never had it on ramps when I visited the exhaust place, just spoke to the guy, he reckoned top ones a CAT abd second one is a GPF ?, The last time it was in the air I had a look at the top cat but I couldn’t see properly whether there were any weld marks from where it may have been gutted and re-welded. It didn’t look as though it did.
Ideally if I could get the diameter of my downpipe then where the 2nd CAT has been totally removed and straight piped, I will opt for a quality 200 cell sports CAT to be welded back in, surely that should get me back within legal tolerance limits and reduce pungent smell.

If that much of the cat & GPF etc has been removed that its causing a "pungent" smell it must be throwing up fault codes like mad as the reading from the lambda sensors will way outside the ECU map allowances...it should also be throwing up dash lights...the fact it isn't makes be suspect it may have a remap to code out the sensors??...not 100% certain about yours.....but when I had 2 x 200cell race cats on my previous VAG car it would throw up codes basically running too lean...& the ECU light on the dash would light up after about the first 500miles after running the cat & any subsequent code reset...

 

[Aaron1875]

They’ve been mapped out as part of a remap, so it’s not running lean and I’ve got no error lights,

 

[Aaron1875]

Albeit the pungent smell is only on start up but it’s not really bad but definitely discernible to my OCD. I just want it compliant.

 

[golfdave]

They’ve been mapped out as part of a remap, so it’s not running lean and I’ve got no error lights,

As I suspencted...so as soon as you refit the cats/GPF it'll alter the readings & the ECU will then alter the fuelling to suit...which will be wrong.....basically the process is that the lambda sensor closest to the engine block takes a reading...the exhaust gases pass through the cats/GPF & then pass the second lambda sensor, which takes another reading. This last reading is compared to the first reading. The ECU compares the two readings to see how much the exhaust pollutants have been cleaned (scrubbed by the cats) for any given engine load/rpm etc.....If the percentage of scrub is too much or too little it then alters the fuelling to compensate....

So if you're trying to fit different cats etc from how the car is when the bought it second hand, then the ECU will need altering also....

 

[Aaron1875]

The lamda sensors have been bypassed via software update in ECU, so if I was to put an upgraded sports cell CAT in, it wouldn’t alter readings to ECU, but would scrub some of the pollutants. However it’s probably wishful thinking that a CAT maybe welded in where the 2nd one used to be located. If I was to put the original replacement downpipe in then it may be worthwhile removing the CAT bypass software.

 

[golfdave]

The lamda sensors have been bypassed via software update in ECU, so if I was to put an upgraded sports cell CAT in, it wouldn’t alter readings to ECU, but would scrub some of the pollutants. However it’s probably wishful thinking that a CAT maybe welded in where the 2nd one used to be located. If I was to put the original replacement downpipe in then it may be worthwhile removing the CAT bypass software.

Lambda delete via software I just don't like...its just a bodge job in my book....totally unnecessary for a road car..

 

[Aaron1875]

Tell me about it, I’m scouring breakers for another Downpipe,