That is the question

Getting a full custom exhaust fitted on the 15th and I know a diesel doesn't need a cat. But after speaking to the guy who remapped my car he said I'd more than likely loose power than gain power with a de cat as it does virtually nothing for the car nor do I need my map tweaked to suit the de cat either

I know people on here have de cats so my question is did you notice a difference? And bhp and torque increase? Did anyone notice Zero difference?

The guy who mapped my car had a Polo GT TDI running 215bhp with the cat still in and knows his stuff with tuning cars as he's been remapping cars and tuning his own for years and actually works for vw too. He himself now runs a Mk6 Golf GTI which at current is 295bhp and has a bigger turbo waiting to go on which will see him at 360bhp

Any help is appreciated to help me decided cat in or cat out

Sounds like the guy tuning your car knows his stuff. Normaly with a diesel, the less exhaust back pressure the better, as there is no need for exhaust scavenging. With a VNT Turbo, things get a bit more complicated. To be honest, I don't think it will make much difference, but I would leave the cat in the system. Save the planet and all that. It wont fail an MOT without a cat, as it's a simple smoke density test at MOT time. However you will be sticking out some foul gases with the cat removed.

i went for a full miltek and decat on a generic map and saw gains of 23ftlb & 11bhp on a pd130

I had my cat chopped out and a pipe of pipe welded in its place.

Doesnt sound any different from inside the car, but does when you stand at the back of the car with it running, sounds more 'whistly'

Didnt notice any extra power etc, although the rest of the exhaust is standard

And it smells a bit more too when its running in a confined space (workshop etc)

The cats getting flanged so can always leave it out for a day or two and see if it feels any better or any worse

I know it's not needed for an MOT. But with the exhaust gonna have nothing on it but pipe as theirs gonna be no silencers or back box just turbo back.

He said it's up to me as it's hit or miss with de cats

De-cat.

de-cat. Basically for a TDI the less back pressure the better so the best exhaust is a short, wide one, which is why I have a 2.5" straight out the side with just one silencer to keep the noise down a bit. No cat of course,

Will 2 1/4 inch pipe be restrictive or ok?

2.25" is still bigger than stock, so will be an improvement.

Wat would u reccomend mate 2.5 or 2.25?

Well, if you're keeping the stock downpipe, 2.25" would be fine to me. I only went for big bore throughout as I have a big bore downpipe right off the turbo @ 2.5" so wanted to keep that going right through.

Yeh keeping the stock downpipe buddy for now anyways as I cba changing the clutch and flywheel till needed lol

Cheers Jason

Mine has been flanged for about 18 months now, and remapped and flange-catted for 12 months.

No problems so far, and sounds pretty sweet at full chat.

Cheers Joel can't wait at all

Hopefully get the kinda noises I want from it. Gonna save for a new induction kit. Fancy a piper cross viper ram air system. Gonna get stainless pipe made for my bmc at current though