Originally Posted by anielsen71
Hmm...This is very interesting information.
I really look forward to get my downpipe fitted and get the car reampped once again after that :-)
But it makes me wonder....Aren't there any alternative solutions for the particle problem that doesn't have the negative sideeffect of the filter restraining the airflow in the exhaust?
How is the law in the UK? Is it illegal there to remove the DPF on cars that are fitted with this from the factory or?
I think it is here in Denmark and thats why I will keep my OEM downpipe to fit every second year at MOT test.
There is a lot of scaremongering going on at the moment regards MOT testing and changes to the test. I have heard of not a single failure, even by our mainland Europe customers.
It has always been the case that tampering with the emissions system "should" make the car fail an MOT however, like HID bulbs and Aero Wipers the cars continue to pass.
(Below is partially extracted from previous replies I have made on this subject... i can't type that fast :-P )
There are a few things to consider here -
1. An MOT tester is not allowed to remove any covers during the test.
2. There is no change to the testing method on diesel vehicles in 2012 however the smoke limit has been reduced by 50% from 3.0 to 1.5
3. A DPF installed BMW will on average score 0.1 with the DPF installed and 0.5 with the DPF OFF. (1/3 of the new low pass limit)
4. There is currently no way of testing for the presence of a catalytic converter on a diesel through exhaust emissions... they don't even produce a reading on the petrol cat tester.
5. Catalytic converters and DPF’s are now available integrated to pipe work seamlessly therefore visually it would be impossible to tell if there is one installed.
6. MOT testers tend to work on many varied vehicles as opposed to multiple brands therefore it would be very difficult and time consuming for an MOT tester to know if a cat had been installed as standard or not. Our 2006 Mercedes Viano never had one from the factory only silencers.
7. CAT's on diesels are for odour control only as they assist in condensing the sulphur vapour however, now that new low sulphur fuels are in place even this is not so much of an issue any more.
Some more info.... >
In diesel engines, conditions in the engine differ from the spark-ignition engine, since power is directly controlled by the fuel supply, rather than by controlling the air supply. Thus when the engine runs at low power, there is more than enough oxygen present to burn the fuel, and diesel engines only make significant amounts of carbon monoxide when running under a load, much less so on turbocharged models where air content is much higher than required.
Diesel exhaust is well known for its characteristic smell; but in Europe this smell in recent years has become much less because the sulphur is now removed from the fuel in the oil refinery, plus the effect of catalytic converters.
I am confident that somewhere in the country there will be a tester who will try to fail a car but it's really as simple as asking him to prove a cat or DPF is not fitted... unless he wants to get the chop saw out, it's impossible and given he only has set tools to use, can't even remove a cover and the smoke limit is completely acceptable, he's hardly going down that road.
The worst possible pollutants are particulates(smoke) and given that our product still leaves a car well below the threshold along with a reduction in overall fuel consumption, we feel we are doing the environment a favour... it's a shame about the red tape and legislation that often has more to do with money making than the environment or the end user.
We do offer different versions of our DPF removal downpipes... our sports cat versions have become more popular recently and is actually what I have fitted to my own X5 35D... This makes absolutely sure that there is no odour and looks quite oem... it's more expensive naturally but there is absolutely no compromise on performance with this part.
X35D DPF OFF Sports Cat