MK5 Golf GTI

All Things Mk5 => Modifications & Technical Area => Performance Modifications => Topic started by: Trekmeister on February 12, 2012, 06:41:31 pm

Title: Decat GT TDI?
Post by: Trekmeister on February 12, 2012, 06:41:31 pm
Exhaust question: How many cats does a GT TDI 140 have, is it two, one on downpipe and the cat back? If so would having adecat downpipe make any difference when remapped to stage one and would this increase chance of failure at MOT (Emissions etc?)

Thanks in advance

Paul
Title: Re: Decat GT TDI?
Post by: vRSAlex on February 12, 2012, 07:00:36 pm
Just the one cat on the pd140.  Straight after the turbo.  I've found that they smooth out the boost and allow the car to rev better.

No issues at mot as they don't test emissions on dervs, just soot test.
Title: Re: Re: Re: Decat GT TDI?
Post by: Trekmeister on February 12, 2012, 07:07:11 pm
Just the one cat on the pd140.  Straight after the turbo.  I've found that they smooth out the boost and allow the car to rev better.

No issues at mot as they don't test emissions on dervs, just soot test.
I was under the impression the GT has a cat back

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Title: Re: Decat GT TDI?
Post by: vRSAlex on February 12, 2012, 07:10:47 pm
They call the exhaust section that goes from the cat section the 'cat back'.  So if the cat is in the downpipe then the rest of the system is called the cat back.
Title: Re: Re: Re: Decat GT TDI?
Post by: Trekmeister on February 12, 2012, 07:22:43 pm
They call the exhaust section that goes from the cat section the 'cat back'.  So if the cat is in the downpipe then the rest of the system is called the cat back.
That makes sense now, would removing the cat be recommended, would it give any performance enhancement and would it increase soot coming out the rear?

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Title: Re: Decat GT TDI?
Post by: Andy on February 12, 2012, 07:30:34 pm
I have a full milly on mine,with out the cat.the car revs a lot better,the only time it smokes is when first started when cold but soon goes away  with no smoke out of mine,read my build thread,pics in there of my exhaust
Title: Re: Re: Decat GT TDI?
Post by: Trekmeister on February 12, 2012, 07:37:37 pm
Is it true that new MOT rules state if a cat is removed when one was fitted as standard will now become a fail?

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Title: Re: Decat GT TDI?
Post by: Andy on February 12, 2012, 07:39:23 pm
Not on a diesel
Title: Re: Decat GT TDI?
Post by: GNJ_Motorsport on February 12, 2012, 09:58:59 pm
Interesting to see what people have done to their 140 TDI's as I think I'll be buying one when I pluck up the courage to sell my S3. I'll be happy with 40+mpg and 180bhp and a load of torque I think for a couple of years.

I've never heard one with a Milltek on, what is the advantage sound wise?
Title: Re: Decat GT TDI?
Post by: Andy on February 12, 2012, 10:28:41 pm
The sound it gives out is  a nice throaty sound but its very quite on the motor way,mpg I got 56
Title: Re: Re: Re: Decat GT TDI?
Post by: Trekmeister on February 12, 2012, 10:49:46 pm
The sound it gives out is  a nice throaty sound but its very quite on the motor way,mpg I got 56
56mpg, at what sort of speed, 55mph?

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Title: Re: Decat GT TDI?
Post by: Jogon on February 12, 2012, 10:53:03 pm
I've got a de-cat full milly , very happy with mine , can't really hear it through town , but up to 3500 revs it sounds good , but after that it sounds the t:ts.

My motor has kept up with focus st's and returns 50+ mpg on a run......
Title: Re: Decat GT TDI?
Post by: Richie18-1987 on February 12, 2012, 11:37:58 pm
Does the de-cat for the golf tdi 140 also fit the jetta tdi 140 as i wanna purchase one but the right one?

Rich.
Title: Re: Decat GT TDI?
Post by: vRSAlex on February 13, 2012, 06:59:47 am
Does the de-cat for the golf tdi 140 also fit the jetta tdi 140 as i wanna purchase one but the right one?

Rich.

Yep.
Title: Re: Decat GT TDI?
Post by: Andy on February 13, 2012, 07:50:27 am
The sound it gives out is  a nice throaty sound but its very quite on the motor way,mpg I got 56
56mpg, at what sort of speed, 55mph?

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doing 70mph
Does the de-cat for the golf tdi 140 also fit the jetta tdi 140 as i wanna purchase one but the right one?

Rich.
thing the tail pipe is longer but the d/p is the same
Title: Re: Decat GT TDI?
Post by: flipmyflipper on February 16, 2012, 03:25:03 pm
Won't it put extra pressure on the turbo seals if you decat it? mine has done nearly 100k, would that be a good idea or temping fate?
Title: Re: Re: Re: Decat GT TDI?
Post by: Trekmeister on February 18, 2012, 11:20:23 am
Won't it put extra pressure on the turbo seals if you decat it? mine has done nearly 100k, would that be a good idea or temping fate?
Interesting point, hope someone has an answer to that

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Title: Re: Decat GT TDI?
Post by: Andy on February 18, 2012, 02:48:24 pm
No i wouldn't of thought so
Title: Re: Decat GT TDI?
Post by: jonbmx900 on February 18, 2012, 05:34:06 pm
I just cut the insides of my cat out no difference in sound still looks like its fitted and made it feel smoother down low