New MOT rules regarding DPF

[robinh112]

Hi whats your thoughts on DPF Gut vs Downpipe, was going to gut the DPF because MOT was only a visual inspection but apparently new laws are coming in force in May 2017. So is there no point in gutting? My thinking is to now get a downpipe and keep my DPF that is working fine just in case I want to go back to stock.

 

[Tyler Davies]

Any car that was originally fitted with DPF will be checked at MOT to ensure it's still present


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[Mario]

What new laws? Other than the smoke test and a visual inspection how can they tell?? Both of those are done at the MOT already.

 

[DrEskimo]

What new laws? Other than the smoke test and a visual inspection how can they tell?? Both of those are done at the MOT already.

I suspect he means the push for new methods of detecting DPF removal because, as you rightly point out, smoke tests and visual inspections are woefully insensitive.

http://garagewire.co.uk/news/mot-changes-to-be-introduced-in-may-following-dpf-investigation/

Quite what this will be, and whether it will be practical is unclear.

 

[Mario]

I suspect he means the push for new methods of detecting DPF removal because, as you rightly point out, smoke tests and visual inspections are woefully insensitive.

http://garagewire.co.uk/news/mot-changes-to-be-introduced-in-may-following-dpf-investigation/

Quite what this will be, and whether it will be practical is unclear.

Thing is, on petrol cars the only tests they have are a visual inspection and the emissions tester up the pipe. A lot of petrol cars out there can pass the test up the pipe with the CAT being removed or gutted out, just like the diesels and their DPF's....they never made any changes to incorporate additional checks for petrol cars which have been able to "get by" for years, so why are they now suddenly looking to crack down on diesels?

 

[DrEskimo]

Thing is, on petrol cars the only tests they have are a visual inspection and the emissions tester up the pipe. A lot of petrol cars out there can pass the test up the pipe with the CAT being removed or gutted out, just like the diesels and their DPF's....they never made any changes to incorporate additional checks for petrol cars which have been able to "get by" for years, so why are they now suddenly looking to crack down on diesels?

*Shrugs*

At an educated guess, they are different for these reasons:

The VAG scandal with diesels has sparked it

Since it's surrounding NOx and the increasing evidence of their effects health, and Petrols emit far far less NOx than diesels.

Relative to DPFs, CATs don't fail nearly as much, so their removal is mainly for performance and much less common than DPF removal.

What is the quantifiable difference in NOx emissions ( and other emissions for that matter..) when comparing a petrol with and without a CAT? I bet it's no where close to the difference between a diesel with and without a DPF, given that petrols emit far less NOx in the first place. Might be wrong though.

Just some ideas there, but yea it's a fair point.