DE-cat 2.5 TDI

[jonplace]

has anybody done a De-cat on their 2.5 TDI ?
I also own a rover 25 TDI and its fairly common with the rover TD comunity to remove the honeycomb centre from the cat, reducing lag and helping to eliminate the lack of power below 1800rpm.

 

[Drizz]

Arent they more smokey?

 

[daver]

Hi there,

I have a 1.9tdi. I removed the honeycomb from mine because of the poor replacement cats I got form german and swedish.
The honeycomb had come loose in my cat, so I opted ror a new one at just under £200 from G&S, paid a garage £70 to fit it and I was happy for 7 months until the cat came apart completely.

Under warranty G&S replaced the cat and also paid for the labour costs to have the cat replaced again, the new one was much stronger looking with a bigger bit of flexi pipe that the first cat was missing. Well 7-8 months later same thing broke at the welds, thought maybe I had a mount damaged or something, but my engine is transverse

Removed the Cat myself this time and still have got to go get my money back from G&S, but decided to remove the honey come with a hammer and a big screwdriver, 15 min job, replaced the empty pipe (Audi one) that had done 130K and its still going strong, you get a bit more smoke on start up but that is about it. Its ok any other time.

Dont know about the MOT yet but will find that out in about 4 months time

Regards

Dave

 

[A3-frankie]

what about performance dave?

 

[jonplace]

regarding the MOT - its a legal requirement to have a CAT fitted so replacing the CAT with a straight through pipe could be an issue come MOT day. The fact that the CAT is empty could not be discovered without removing the cat and looking inside. My rover 25TD has just sailed through its 2nd MOT with no CAT.
I havnt noticed any increase in smoke, would probably be looking at fuelling / air issues if i was getting excessive smoke, not the CAT.
regarding performance - on the rover its certainly helped reduce turbo lag and give a more free revving feel to the engine. The 2.5TDI seems to suffer quite badly from turbo lag and I wonder if a more free flowing exhaust would help reduce the black spot below 1800rpm.
I had a peek at the exhaust the other day and it doesnt look like an easy job.

 

[james0808]

what about performance dave?

I would like to know also.

 

[daver]

Lo Guys,

Did not notice a huge difference, maybe a bit smoother. Only thing is I have an alpin tuning box on my car, and have been getting a lot fo problems with the car going into Limp mode, took the box off and still limp mode when on the motorway for long periods of time.

I am going to change the Vac hoses on the turbo when I get time and also the N70 valve as I believe that can cause premature limp mode.

But yes when I did the de-cat it was motther, but I only did it because I had no other choice but to go buy a brand new one form Audi at the cos tof a small fortune. these aftermarket ones are crap.

My advise is wait until the honeycomb comes loose in the box, ie faulty then to the mod, after all you have nothing to loose then and its only 6 bolts on my car and a couple of new gasket

Anyone know where to get a decent set of hoses for my turbo apart form Audi

Rgds......DAve