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getting an MOT without a cat

5K views 48 replies 23 participants last post by  Goginawa 
#1 ·
My EVO doesn’t have a Cat and has failed it’s MOT on emissions. Is there a way around this?
Ta
Jx
 
#11 · (Edited)
Unless the law is indicative and states that one needs a catalytic converter present so as for the car to be able to take the MOT test, then there is no actual need for a catalytic converter to pass the emission test. HC, CO , CO2, can be mapped out to conform to the appropriate requested values the emission test dictates, once these are mapped out NOX will sort itself out. If you are on factory mapping, you'll not pass the test without a euro3 200cel cat, or a stock cat.


If you are on stock ecu/mapping, you really need to put the stock cat on it, as the ecu is mapped for emissions on that specific stock cat. The evo 8 cat, should get you through though, the two cats differ not only in external dimensions but in internal characteristics, as far as the combination of precious metals used, and that creates an incompatibility between the stock mapping and the cat, but if I remember correctly it is not at such degree that will not allow you to pass emissions. You also need to make sure that the oem O2 sensor is in proper working order and it reads properly.




Marios
 
#14 ·
Unless the law is indicative and states that one needs a catalytic converter present so as for the car to be able to take the MOT test, then there is no actual need for a catalytic converter to pass the emission test. HC, CO , CO2, can be mapped out to conform to the appropriate requested values the emission test dictates, once these are mapped out NOX will sort itself out. If you are on factory mapping, you'll not pass the test without a euro3 200cel cat, or a stock cat.

If you are on stock ecu/mapping, you really need to put the stock cat on it, as the ecu is mapped for emissions on that specific stock cat. The evo 8 cat, should get you through though, the two cats differ not only in external dimensions but in internal characteristics, as far as the combination of precious metals used, and that creates an incompatibility between the stock mapping and the cat, but if I remember correctly it is not at such degree that will not allow you to pass emissions. You also need to make sure that the oem O2 sensor is in proper working order and it reads properly.

Marios
Does this mapping adjustment apply to other Lancer models ? Can the Ralliart Sportback be tweaked in this way as I run the car decatted but put the cat back on for the mot.
Cheers
Brian.
 
#13 ·
My EVO doesn't have a Cat and has failed it's MOT on emissions. Is there a way around this?
Ta
Jx
Mine is a 6 . I had a Cat off an 8 which is longer but we bodged it on and it still failed!
PM if anyone knows a dodgy one!
Jx
Did you get the cat really hot just before testing the emissions, this often needs to be done to get evo's to pass

Stu
 
#16 ·
Very very hard if not impossible to pass a genuine UK Mot emissions test without a cat despite what some are saying, ive heard of people spending a lot of time playing around with the mapping specifically to try and get it through but cant remember if it did eventually pass or not, the numbers it needs to hit on emissions cat test are so tight that without a good working cat or a friendly/dodgy mot tester you wont get it through.
 
#19 · (Edited)
Then those people did not know what they were actually doing, if one is competent with a specific ecu/software and is aware of the specific MOT requirements, then emissions can be passed without a catalytic converter, it makes no difference what the demanded values are and it does not take much time either, and I do know this because I have actually done it myself. A catalytic converter converts CO, CO2 by oxygenizing it, it also partially retains NOX and HC, if one in his tuning manages to retain low enough CO,CO2 and HC levels, then imperatively NOX will also be at minimal levels and thus all emissions will be within the MOT requirements.

And something on catalytic converters. These were firstly used widely on production cars in the 80s. They were created as a means to protect the environment, but also as another selling product/part that would inevitably fail in its life and would need to be replaced. It was created because the fuel composition and formulas of that age was very polluting ito the environment mostly because it contained a lot of lead. Due to this fact, a filter-converter needed to be made to reduce the excessive polluting effect of leaded fuel formulas of that age. Catalytic converters used to fail much sooner back then than they do today, mainly due to lead. Also benzene and other hydrocarbons were not as refined as they are today, and most cars were carburated and without an ecu unit. But even later on when most cars got an ecu unit, the unit was not as capable and consistent in retaining an idle i.e of certain emission output without a catalytic converter. The converter although modified as today's fuel are not using lead, was kept to this day by the automotive industry because it continues to bring money in and they have no reason to abolish it whatsoever, on the contrary they also installed it on diesel cars also.

Marios
 
#20 ·
Regardless an UK MOT requires a car to have a cat fitted AND pass its emissions, passing emissions alone is not good enough to pass an MOT.
 
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#21 ·
Same here, so he needs to find a good working order cat , preferably one for his evo model.

Marios
 
#32 · (Edited)
Enough moronic comments on this thread , that are put there just for the sake of it, by people who are clueless about ecu tuning or automotive engineering vs actual environmental pollution or the manufacturing of a catalytic converter and its actual efficiency. The main reasons catalytic converters are still in use, is mere profit by the automotive industry. The majority of catalytic converters tend to fail a few years after the warranty on them has expired. The owner is forced to buy a new one. Also the rules, regulations and restrictions that have been placed as "proper" in regards to what emissions levels should be and what type of catalytic converter is acceptable are also in favor of the use of specific catalytic converters, and not to what actually is harmful for the atmosphere.


An MOT focuses on idle/standing rev emissions only, that is a very small load area in regards to the whole and complexity of the entire load area an engine needs in order to function properly. This idle load area has nothing to do with how much power the car makes nor does it affect its power output or general function of an engine. Also at high gas speed and velocity, which is where an engine spends 99% of its life, a catalytic converter in the way its types are manufactured today has very little effect on oxygenizing CO and CO2 and in restraining HC to the right levels that would make these not harmful for the environment, especially on the rich OEM mapping.







Marios
 
#33 ·
Enough moronic comments on this thread , that are put there just for the sake of it, by people who are clueless about ecu tuning or automotive engineering vs actual environmental pollution or the manufacturing of a catalytic converter and its actual efficiency. The main reasons catalytic converters are still in use, is mere profit by the automotive industry.

Marios
:rotz::crackup:
 
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