Get rid of those cats

smurphy · Nov 13, 2008

Hi all Ive put me disco back together all runing well. Now what I'm after is de-cat pipes for it and I don't know wheres best. It's a 1995 3.9 V8 on LPG and Ive been to see the MOT guy and asked him if I need em and he says that they have to test the emission's in what I tell him to.

discool · Nov 13, 2008

You can get certainly get a Y pipe without the cats. But can get the pipe without the cats but with mountings for your Lambda sensors is the question, or do you intend to remove them as well?
You can get 'de-restricted' cats complete with Y pipe, Janspeed for one do them.
Removing both your catalytic converters will increase your exhaust emissions when using petrol.

Have a look at this link.. http://www.lro.com/forum/viewtopic.php?t=22591&start=0

smurphy · Nov 13, 2008

Removing both your catalytic converters will increase your exhaust emissions when using petrol.

It don't matter about the petrol emissions as it will be tested in gas

, also i always run in gas i think ive put a fiver petrol in it in about the last month.

Thanks for the link i think I'll go for straight through pipe and if i have to I'll weld fittings for the sensors back on after. As I dont think it'll run right without them.

Dorset VogueSE · Nov 14, 2008

smurphy said:
It don't matter about the petrol emissions as it will be tested in gas , also i always run in gas i think ive put a fiver petrol in it in about the last month.

just a word of caution before ditching the cats completely.......

Although the MoT centre should test the vehicle on whatever fuel it is presented, I found the gas system had been turned off when I took my Range Rover for its test.

Apparantly the garage should use a 'conversion factor' or something on the emmision test if running on gas. It seems a lot can't be bothered so switch it back to petrol, in which case it will fail the test.

metallicachick86 · Nov 14, 2008

have a read here and see what you think you should do

mot manual

theres two sections in spark emmisions test, non cats and cats, and it tells you the workin out they do for lpg and dual exhaust systems

smurphy · Nov 14, 2008

I have read that MOT manual, I also know the tester so he'll make sure that it is gas for me. I think that I'll modify the pipes that are on for now, by cutting the cats off and welding in a piece of pipe.

Disco Inferno · Nov 14, 2008

I know I will be corrected if im wrong but I beleive that any petrol vehicle registered after Jan 93 has to have a cat fitted or it will fail its mot even if the emmisions are within tolarances. Not that hard to spot that it hasnt got cats when its on a ramp being proded during an mot test.

discool · Nov 14, 2008

Disco Inferno said:
I know I will be corrected if im wrong but I beleive that any petrol vehicle registered after Jan 93 has to have a cat fitted or it will fail its mot even if the emmisions are within tolarances. Not that hard to spot that it hasnt got cats when its on a ramp being proded during an mot test.

Can't find anything refuring to this in the link provided by metallicachick86
May be I should I go to specsavers

smurphy · Nov 15, 2008

discool said:
Can't find anything refuring the this in the link provided by metallicachick86
May be I should I go to specsavers

Hope my mate the MOT tester will need to go too

acc · Nov 15, 2008

I removed the cats on my 1993 Rangie 3.9, got the down pipes etc from Rimmer Bros. The pipes had the ports for the Lambarda sensors. They still need to be there to keep the ECU happy.

My MOT tester told me that if it's fitted with cats it has to be tested with cats. When we put it through the emmisions part of the test the readings were in fact lower than with cats. Also the cats act as a restricter in the exhaust, my 3.9 ran much better without them.

smurphy · Nov 15, 2008

acc said:
I removed the cats on my 1993 Rangie 3.9, got the down pipes etc from Rimmer Bros. The pipes had the ports for the Lambarda sensors. They still need to be there to keep the ECU happy.

My MOT tester told me that if it's fitted with cats it has to be tested with cats. When we put it through the emissions part of the test the readings were in fact lower than with cats. Also the cats act as a restricter in the exhaust, my 3.9 ran much better without them.

So it did pass the MOT then, I'm in the understanding that they don't have be there. Also if they pass the emissions test they'll pass them anyhow. My father in-law had a Golf VR6 he had the cat removed on that and it still passed emissions. He keeped his cat just in-case he didn't, but I think mine will pass in LPG anyway. Is their anyone that knows someone that didn't pass emissions on gas?

mrnice · Nov 15, 2008

i own a 96 LPG 3.9V8efi disco and i was told by janspeed when i phoned em that "if you drive it in on gas they are obliged by law to test it on gas", it passed anyway. It appears that this is even a bit of a grey area with most m o t testers so your best bet is to have an ask around, find a mechanic who will test it on LPG for you and use him. Ive had a lot of contradictory advice when asking mot testers what is required with various things to pass my mot.

smurphy · Nov 15, 2008

mrnice said:
i own a 96 LPG 3.9V8efi disco and i was told by janspeed when i phoned em that "if you drive it in on gas they are obliged by law to test it on gas", it passed anyway.

That's good to hear I think Ill bite the bullet and just get rid. Ill deal wit the consequences if it arises. Thanks for everybodys input.:clap2:

acc · Nov 15, 2008

smurphy posted
So it did pass the MOT then, I'm in the understanding that they don't have be there. Also if they pass the emissions test they'll pass them anyhow.

No probs went through every year for 3 years after I did away with the cats. Then a diesel came my way and I couldn't afford both.

Get rid of those cats

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