Richard Martin
Well-Known Member
I don't know about the V8, but on the 300TDI you have to pass the emissions test at the MOT and you can pass it without a cat
sierrafery
Well-Known Member
As far as i know, on petrol cars if u remove the cat u'll have to remap the ECM addapting it for the new values cos the lambda sensors will give erratic inputs f***ing up the engine management......but dont trust me 100% either.
discool
Well-Known Member
Cats are not a legal requirment on petrol engine vehicles and they are not an MOT testable item.
The exhaust emissions only are tested and if they do not exceed the levels for that particular vehicle/engine it will pass.
Exhaust emmissions on Tdi's are not tested only a smoke test is done on diesels.
The exhaust emissions only are tested and if they do not exceed the levels for that particular vehicle/engine it will pass.
Exhaust emmissions on Tdi's are not tested only a smoke test is done on diesels.
discool
Well-Known Member
Getting very flashy aren't we alex 
The only way a standard "modern" petrol engine can meet the emission rules now is with cat/s fitted even lean burn engines are fitted with them.
But if with the removal of the cat and then with engine modifications the emissions level for that engine are not exceeded so be it, that's ok.
The only way a standard "modern" petrol engine can meet the emission rules now is with cat/s fitted even lean burn engines are fitted with them.
But if with the removal of the cat and then with engine modifications the emissions level for that engine are not exceeded so be it, that's ok.
spanishlair
New Member
What benifit could you obtain by taking off the Cat. Its a 17 year old petrol V8, it will need all the help it can get to pass emissions. I can see the benifit/logic in a diesel... but petrol V8?
nathan5346
Well-Known Member
Better noise n performance?
discool
Well-Known Member
As nathan above, once there was a 3.5 and then restrictive cat's were introduce so what did LR do increase the capacity to 3.9.
So remove the restrictive cat's retune the engine to suit and wow more power so you have a fast or shall we say a faster vehicle.
But then does a disco 1 or 2 need this extra power?? No I don't think so but some do which is ok.
So remove the restrictive cat's retune the engine to suit and wow more power so you have a fast or shall we say a faster vehicle.
But then does a disco 1 or 2 need this extra power?? No I don't think so but some do which is ok.
disco2shaun
New Member
well your wrong!! catalytic converters are a legal requirement on petrol cars from 1997 onwards. also my old 300tdi defender failed its m.o.t at my work last week due to the emisions been to high and emitting to much smoke for a turbo charged engine. if you remove the cat from a petrol car you will have to replace it for when its due an m.o.t
oldskool
Well-Known Member
But a petrol engin won't pass a its emmission test without the cat if its supposed to have one, the only cars i know of thet didnt have cats fitted were susuki's cos they went the lean burn instead.
disco2shaun
New Member
sorry a legal requirement on a m.o.t test. we had a bmw m3 other day for an m.o.t and would it hell go through the emmisions because its had a de-cat
oldskool
Well-Known Member
1993 actuatly.
