Golf 5 1.9tdi Catalytic Convertor

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sanelenanti
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Golf 5 1.9tdi Catalytic Convertor

Post by sanelenanti »

Hi guys

May you kindly assist.
I was chatting to a guy from a Shop that recondition turbos and he asked if I still have the Catalytic convertor on my TDI and he suggested that I remove it since it's the culprit on turbo failures.
How true is this?
Has anyone done it?
How does the car perform after doing this ?
Will there be a damage that might surface in future?

Your inputs are appreciated.
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Re: Golf 5 1.9tdi Catalytic Convertor

Post by BIGMIG »

Mileage of the car?
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sanelenanti
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Re: Golf 5 1.9tdi Catalytic Convertor

Post by sanelenanti »

It's currently sitting at 282000
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Re: Golf 5 1.9tdi Catalytic Convertor

Post by VGTI »

My Polo has done 355000 now and it still has the CAT fitted... however, I have been wondering lately about the thing, it is definitely more laggy but I don't get any underboost errors so I am not sure if it is a sticky vanes issue.

Will have to maybe remove the CAT and see if it makes a difference!
'04 Polo TDI 1661.9 km on 58.05l
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Ashveer03
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Re: Golf 5 1.9tdi Catalytic Convertor

Post by Ashveer03 »

sanelenanti wrote:Hi guys

May you kindly assist.
I was chatting to a guy from a Shop that recondition turbos and he asked if I still have the Catalytic convertor on my TDI and he suggested that I remove it since it's the culprit on turbo failures.
How true is this?
Has anyone done it?
How does the car perform after doing this ?
Will there be a damage that might surface in future?

Your inputs are appreciated.
Everybody does it. Diesel cats generally last longer than petrol cats, then again it depends on how u drive and what fuel is being used.
I would say at 300k kms it should be pretty gunked up, i would get it removed..

Normally (on other engines) when a cat is about blocked, the manifold is the next weakest link, it cracks to allow the engine to exhaust and keep it running.
But the vw tdi manifolds are cast iron, not very easy to crack that makes the turbo the next weakest link..

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Re: Golf 5 1.9tdi Catalytic Convertor

Post by Ashveer03 »

VGTI wrote:My Polo has done 355000 now and it still has the CAT fitted... however, I have been wondering lately about the thing, it is definitely more laggy but I don't get any underboost errors so I am not sure if it is a sticky vanes issue.

Will have to maybe remove the CAT and see if it makes a difference!
Im quite sure u would feel a difference on performance and economy

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Re: Golf 5 1.9tdi Catalytic Convertor

Post by BIGMIG »

Just bash it out and be done with it, no negative side affects.
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Re: Golf 5 1.9tdi Catalytic Convertor

Post by VAG Fan »

In my (limited) experience, a turbo with a semi-stuck VNT mechanism may run into overboost more regularly, once the cat monolith has been removed. There is no restriction anymore on the exhaust side, so it will spool up more readily. Obviously, the sticky VNT is the actual problem. I'm just saying that a cat delete accentuates this problem. Before the cat delete, mine would only go into overboost when cruising on the highway. After cat delete, it would even happen regularly in my daily commute, under gentle acceleration.
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2004 VW Golf TDI, type 1J, AHF, 317k (2016-current) --- daily
1990 VW Fox, type 16, HM, 304k (2005-current) --- spare runaround
Previous:
1992 Audi 500 SE, type C4, AAR (2001-2020) --- nice while it lasted
1983 VW Golf GTS, type 17, FR (1992-2005) --- most fun car I've ever had
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Re: Golf 5 1.9tdi Catalytic Convertor

Post by VGTI »

VAG Fan wrote: Fri Jun 08, 2018 2:46 pm In my (limited) experience, a turbo with a semi-stuck VNT mechanism may run into overboost more regularly, once the cat monolith has been removed. There is no restriction anymore on the exhaust side, so it will spool up more readily. Obviously, the sticky VNT is the actual problem. I'm just saying that a cat delete accentuates this problem. Before the cat delete, mine would only go into overboost when cruising on the highway. After cat delete, it would even happen regularly in my daily commute, under gentle acceleration.
If it under or overboost will it go into limp mode?
'04 Polo TDI 1661.9 km on 58.05l
'13 Hyundai Santa Fe 2.2 Elite
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Re: Golf 5 1.9tdi Catalytic Convertor

Post by VAG Fan »

I can only speak for the AHF engine in the Mk 4, and only for overboost, because that's what I've experienced. If the overboost is severe enough, or prolonged enough, then yes, it does go into limp mode.
Mark R.
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2004 VW Golf TDI, type 1J, AHF, 317k (2016-current) --- daily
1990 VW Fox, type 16, HM, 304k (2005-current) --- spare runaround
Previous:
1992 Audi 500 SE, type C4, AAR (2001-2020) --- nice while it lasted
1983 VW Golf GTS, type 17, FR (1992-2005) --- most fun car I've ever had
1978 Audi 100 GLS 5E, type 43, WC (1991-92) --- died in the side of a Rekord who cut me off
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Re: Golf 5 1.9tdi Catalytic Convertor

Post by BIGMIG »

Have you run logs to see what the turbo is doing?
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