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Another decat thread - Printable Version

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Another decat thread - aaron_one - 19-05-2012

Hi guys I've looked around a bit but cant find info on what decatting my 2.0 Hdi will actually do. I've read the thread on opening the box up and getting everything out but how will it improve the cars ability? Also do I have to do anything else if I decat it?

Just need a few pointers really. Sounds like a good free way of improving

Another decat thread - Frosty - 19-05-2012

You can do it my changing the pipe that has the cat in, is prob the best way. I expect you can get a de cat pipe on eBay. Then you can either keep the cat or take it to the scrappy to get some dollar for it.

Re: Another decat thread - 4WayDiablo - 19-05-2012

It will help the turbo to spool better and quicker as there is less restriction in the exhaust system
And its not a "cat" as such but a particulate filter :-)

Re: Another decat thread - Pete - 19-05-2012

Whilst on the subject on HDI decats, does anyone know if the decat pipe off an XUD will fit? Got one doing bugger all in the back yard..

PS, Sorry for the hi-jack Aaron.

Re: Another decat thread - 4WayDiablo - 19-05-2012

Don't think so Pete, sure someone will be along soon who knows for sure but I think I remember reading somewhere that they dont

Another decat thread - Matt - 19-05-2012

Give it a try pete. What you got to loose Smile

Re: Another decat thread - Midnightclub - 19-05-2012

IIRC they fit yes but require the flange from the HDi cat pipe swapping over for it to work

Re: Another decat thread - aaron_one - 19-05-2012

So is it worth putting a straight through pipe on instead?
Is there any negative effects from it?

Re: Another decat thread - Midnightclub - 19-05-2012

It depends on whether or not your doing it yourself i guess, never heard of any negative effects caused by de-catting

Re: Another decat thread - ginge191 - 19-05-2012

More like should you be tampering with an exhaust system if you don't know what it would do...

Have you seen "back to the future" , well de-cat, and that is your end product ninja

Re: Another decat thread - Pete - 19-05-2012

Cheers peeps Smile

Aye Aaron, deffo worth doing IMO!

Re: Another decat thread - Toms306 - 19-05-2012

As Phil says, it helps the turbo spool quicker mainly. But it also allows you to get the exhaust gasses out of the cylinder quicker too....pointless shoving lots of air in if you can't get it out quickly..... Smile

Re: Another decat thread - Poodle - 20-05-2012

4WayDiablo Wrote:It will help the turbo to spool better and quicker as there is less restriction in the exhaust system
And its not a "cat" as such but a particulate filter :-)
Ignore this man, it is a cat.

Tom, the easing of the exit pressure is what allows the turbo to spool quicker fella.

And Ginge, is that not what he's trying to find out here..? Stop trolling the newbies and go back to your stone-age engine section where you belong. Tongue

Pete, i've got a feeling the shape of them is slightly different too, seem to remember the bloke who did it before (brad-somebody..?) found it rubbed slightly on the subframe or something.

Re: Another decat thread - Mr Whippy - 20-05-2012

Pete Wrote:Whilst on the subject on HDI decats, does anyone know if the decat pipe off an XUD will fit? Got one doing bugger all in the back yard..

PS, Sorry for the hi-jack Aaron.

Nah they don't unfortunately, the angle is different and it hits the sub-frame.

We tried to make those cheap 'pre-cat' turbo > mid section parts from a Td fit the HDi but they didn't... gutting Big Grin

However, a 1.8 16v or 2.0 16v downpipe fits on, strangely enough... I used one for my HDi exhaust.


I still can't believe no one has made a decent HDi de-cat > mid box pipe. They would sell loads at the right price. Problem is most exhaust places make everything in stainless suddenly making the costs silly and the whole project un-viable.


Dave

Re: Another decat thread - procta - 20-05-2012

the Dturbo de cats fit no bother, just swop the HDi flange over onto it. job done!
heres a photo of it on my HDI. the mot tester took longer printing out the mot paper than he did fitting it!
[Image: 003-2.jpg]
[Image: 001-4.jpg]
pipe only costed £20 from motors discount, and a ps3 game for me mot tester for swoppin it over.
if anyone wants more snaps i can try and get them.

Re: Another decat thread - Dum-Dum - 21-05-2012

Have you read my HDi De-Cat guide in the guides section. ALL the answers to your questions are in there.

Re: Another decat thread - Mr Whippy - 21-05-2012

procta Wrote:the Dturbo de cats fit no bother, just swop the HDi flange over onto it. job done!
heres a photo of it on my HDI. the mot tester took longer printing out the mot paper than he did fitting it!
[Image: 003-2.jpg]
[Image: 001-4.jpg]
pipe only costed £20 from motors discount, and a ps3 game for me mot tester for swoppin it over.
if anyone wants more snaps i can try and get them.


Oooo nice.

Care to share the part number etc.


I think where I'm getting mixed up is that the Td pre-cat part number we used back in the day was for a turbo > end of mid box section or something, since the ones we bought had came with a centre box on too iirc... maybe they went right to the back box.

But if you can get a Td pipe for £20 that fits and goes to the HDi centre box then go for it...! (assuming you are doing the flange swapping of course Smile )


Cheers

Dave

Re: Another decat thread - aaron_one - 21-05-2012

Thanks to the guys who gave sound advice, not back to the future references!

Aye Dave cheers for your advice too, I can ask about it on Thursday morning, I'm booked in for a remap with you!

Re: Another decat thread - procta - 25-05-2012

dave, as i remember its just a Dturbo de cat front pipe, i was shown the book with the exhausts of the 306. the Dturbo and HDis hatch backs use the same centre section and back box. the down pipe ( cat part) and decat part are the same shape and the end that meets the centre section is identical. it was just the flanges were different. swop that over dave and your laughing!
heres what i used,
http://www.ebay.co.uk/itm/Peugeot-306-1 ... 519f782f7e

Re: Another decat thread - ToxicNinjaPoo - 11-06-2012

I was looking at http://www.ebay.co.uk/itm/Peugeot-306-2 ... 357wt_1037 and http://www.ebay.co.uk/itm/Peugeot-306-2 ... 26wt_1037.. Surely that's worth a look at for £100 chaps?!

Re: Another decat thread - lolsteve - 11-06-2012

Cheaper to have box cut out and pipe welded in

Re: Another decat thread - Mr Whippy - 12-06-2012

Yeah it is still technically the easiest solution to chop out/weld in a new bit. Welding flanges is a bit of a pain really, and the angle is just as sensitive to get right as the new welded in straight part.

Plus your parts costs are cheaper (1ft of mild steel pipe off an old exhaust) and you don't have an old downpipe/cat section missing a flange left over, just a cat ready for the scrapper.


I still think there would be value in a de-cat downpipe made to a high spec for the stage 2 people. At that level of tune every extra bit of flow potential at the exhaust outlet is gonna benefit you I think.
I guess at that point though you are then right into the realm of just going to a decent exhaust place and getting a £200 stainless turbo > backbox jobby made any way!

Hmmm

Dave