Td5 Exhaust De-cat

v5dcr · Mar 6, 2008

Hi folks just had my td5 discovery catalytic convertor cut off and a straight bit of pipe put in.
i cant beleive the difference especially at low revs no more reving its nuts off to do the hills this is by far the best mod ive done
only problem is some guy offered me £25 for my cat i could of got £75 at the scrap yard gutted but then again it only cost me £40 to get it cut off so with the £25 for the cat i only spent £15 so cant grumble. the difference is mega and the cat was clogged up.try it folks

simon j · Mar 6, 2008

have been thinking of doing this to mine, even more-so hearing how impressed you are and its worth £75 !!!!

simon j · Mar 13, 2008

am i right in thinking that the cat is the large centre box in the middle of the exhaust ??

PASTMASTER · Mar 13, 2008

simon j said:
am i right in thinking that the cat is the large centre box in the middle of the exhaust ??

The TD5 does not have a cat, unless it's been introduced since 2002. Both silencers should be of standard construction.

bellautos · Mar 13, 2008

simon j said:
am i right in thinking that the cat is the large centre box in the middle of the exhaust ??

The cat is the bulge in the front pipe of the exhaust IF fitted on your model.

simon j · Mar 13, 2008

only have the flexi on the front pipe...99 model...

PASTMASTER · Mar 13, 2008

simon j said:
only have the flexi on the front pipe...99 model...

Have the workshop manual for 99 model. No mention of cats. Or dogs.

thebiglad · Mar 13, 2008

PASTMASTER said:
Have the workshop manual for 99 model. No mention of cats. Or dogs.

I think you'll find that strictly speaking there are no cats on diesel engines - they are what is called particulate filters and as such do not have a catalytic action. Can & do get blocked up.

simon j · Mar 14, 2008

Ok, thanks guys...
looks like i'll stick with the tunit box and blanked egr.. seems to go quite well!!

v5dcr · Mar 14, 2008

i cant beleive people comment on things they no nothing about. some td5 s DO HAVE CATS ask any landy garage and as for the guy who said deisel motors dont have cats just have particulate filters you havnt got a clue honestly ..the cat looks like a middle box nothing flash when you cut it of you see the hex mesh inside THIS IS A CAT not a middle box. and as for performance its a lot better im not saying its breaking my neck with the g force. the guy at a well known garage near me also a freind said when they get well dirty it matters a great deal exhaust gas can only pass slowly. hence why i subaru impreza has a exhaust the diameter of a lamp post......hey and would you beleive it most people de-cat them after there test...

thebiglad · Mar 14, 2008

v5dcr said:
i cant beleive people comment on things they no nothing about.

Well actually I do know something about this.

some td5 s DO HAVE CATS ask any landy garage and as for the guy who said deisel motors dont have cats just have particulate filters you havnt got a clue honestly ..the cat looks like a middle box nothing flash when you cut it of you see the hex mesh inside THIS IS A CAT

Diesel Land Rovers do NOT have catalytic converters, they have particulate filters.

not a middle box. and as for performance its a lot better im not saying its breaking my neck with the g force. the guy at a well known garage near me also a freind said when they get well dirty it matters a great deal

A catalytic converter works on a chemical/atomic level, whereas a particulate filter is just that, a filter. That's why they get "well dirty"

exhaust gas can only pass slowly. hence why i subaru impreza

The subaru is a petrol engined vehicle - they DO have cats!!

has a exhaust the diameter of a lamp post......hey and would you beleive it most people de-cat them after there test...

jt_biker · Mar 14, 2008

Taken from TD5ALIVE web site

Later model Td5's, from 2001 and newer, had a catalyst fitted into the exhaust downpipe (See picture on right). This reduces exhaust noise significantly, and also causes a restriction in the exhaust system, causing the turbo to take longer to reach full boost. This is why these later models are gutless below 2000 rpm! By simply fitting a downpipe from an early model Td5, which is a direct replacement, you can make a dramatic difference to the performance, due to improved exhaust gas flow, and with our exhaust system, you'll get a further boost, and the exhaust note too!

JT

simon j · Mar 14, 2008

so it is the large box in the middle.. it has about 5-6 inch of pipe and a flange on each end,
thanks for clearing things up v5dcr

pindie · Mar 14, 2008

Is this vehicle with no cats in a auto or manual? I find in my auto 03 model cats scream all the time wether up or down hill! They scratch the leather as well.

Seriously though does this make a bigger difference on an auto?

Ta

PASTMASTER · Mar 14, 2008

jt_biker said:
Taken from TD5ALIVE web site

Later model Td5's, from 2001 and newer, had a catalyst fitted into the exhaust downpipe (See picture on right). This reduces exhaust noise significantly, and also causes a restriction in the exhaust system, causing the turbo to take longer to reach full boost. This is why these later models are gutless below 2000 rpm! By simply fitting a downpipe from an early model Td5, which is a direct replacement, you can make a dramatic difference to the performance, due to improved exhaust gas flow, and with our exhaust system, you'll get a further boost, and the exhaust note too!

JT

Thanks for clearing that up JT. As I said, my LR workshop manual doesn't mention them, so I assume they were fitted after May 2002. There was a post a while ago that said it would be an MoT fail to remove them. However how a tester would know I have no idea!

bellautos · Mar 14, 2008

thebiglad said:
I think you'll find that strictly speaking there are no cats on diesel engines - they are what is called particulate filters and as such do not have a catalytic action. Can & do get blocked up.

Yes and no , in the td5 case its a cat see picture. on new model diesels yes partical filters are fitted on some.

Diesel engines
For compression ignition (i.e., Diesel) engines, the most commonly used catalytic converter is the diesel oxidation catalyst. The catalyst uses excess O2 (oxygen) in the exhaust gas stream to oxidize CO (Carbon Monoxide) to CO2 (Carbon Dioxide) and HC (hydrocarbons) to H2O (water) and CO2. These converters often reach 90% effectiveness, virtually eliminating diesel odor and helping to reduce visible particulates (soot), however they are incapable of reducing NOx as chemical reactions always occur in the simplest possible way, and the existing O2 in the exhaust gas stream would react first.
To reduce NOx on a compression ignition engine it is necessary to change the exhaust gas - two main technologies are used for this - selective catalytic reduction (SCR) and NOx (NOx) traps (or NOx Adsorbers).
Another issue for diesel engines is particulate (soot). This can be controlled by a soot trap or diesel particulate filter (DPF), as catalytic converters are unable to affect elemental carbon (however they will remove up to 90% of the soluble organic fraction). A clogging soot filter creates a lot of back pressure decreasing engine performance. However, once clogged, the filter goes through a regeneration cycle where diesel fuel is injected directly into the exhaust stream and the soot is burned off. After the soot has been burned off the regeneration cycle stops and injection of diesel fuel stops. This regeneration cycle should not affect performance of the engine.

Catalytic converter - Wikipedia, the free encyclopedia

bellautos · Mar 14, 2008

And its not part of any MOT test in the current rules/laws

PASTMASTER · Mar 15, 2008

bellautos said:
And its not part of any MOT test in the current rules/laws

I was writing from memory- the info can't have been correct then.

The picture in the BellAutos post is identical to the one in the manual. What is odd is that the manual does not mention a cat. The text IMPLIES that the bulgy bit is the flexible pipe section. I bow to superior knowledge because I've never inspected the part that closely - it just seems odd that there is no mention in the description, nor labelling of the cat in the picture

RobCSH · Mar 15, 2008

http://www.bellautoservices.co.uk/

To reduce NOx on a compression ignition engine it is necessary to change the exhaust gas - two main technologies are used for this - selective catalytic reduction (SCR) and NOx (NOx) traps (or NOx Adsorbers).

Ah, yes. Also known as Adblue, used by a number of commercial vehicle manufacturers, our included.(Volvo)
I hope LR don't go down this route, how would you fancy putting another pump on your motor at the petrol station at 45p a litre and watch it use that as well as diesel? Vehicle owners are not impressed.

Rob

Rickjw · Oct 3, 2019

Hello all, I know this post is old now but its the most relevant thing I can find. My Defender td5 built 99 reg 200 has been failed at U-drive mot for
no catalytic converter. (did not carry out smoke test either) I was sure that it wasn't built with one as it never been mentioned in the 8yrs I have it mot tested and after reading the posts above and talking to a very helpful main dealer (yep really) who confirmed it wasn't.
My problem is, U drive are unhelpful obviousley saying they are right and DVSA (vosa's new name) are as helpful as a chocolate teapot telling me I have to get proof from the manufacture as in Land Rover hq. I have looked at the land rover repair manual and it shows no cat in exhaust section, but I'm sure that wont be accepted.
Has anyone had this issue and how did you resolve it? Can i simply go to another test station?

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