Tuning Diesel: downpipe
- Thread starter johndoe
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Tuning Diesel: downpipe
bencey
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Hi there, what size of engine do you have? does it have a DPF?
Hi! It was intended more as a general 'Bravo-wide' discussion, for all diesel versions...
Mine is a MJ150 without DPF (so relatively easy to get rid of 1 or both cats)
Seems as its illegal to decat in our country id be tempted to start looking at sports cats..
Is it illegal for diesels as well? Of course a bit of a grey area, but I thought as long as they pass the smoke test all is well
... As far as I know there is no requirement to physically check for the presense of a cat... Any MOT experts around to share their knowledge?
I'm not an approved MOT tester but I can read the regulations available at the VOSA website.
See below. Missing CAT is a failure, but only "On vehicles that qualify for a full cat emissions".
The catalyst test is part of the MOT test for most spark ignition petrol engined vehicles with four or more wheels first used on and after 1 August 1992.
Compression Ignition engines are currently only subject to a SMOKE test. Now most modern Euro IV diesels have DPFs (diesel particulate filters) and some/all Euro V have Catalysing DPFs (as I understand it). So on a Euro IV diesel DPF removal is not an MOT failure YET. On a Euro V whilst CAT/DPF removal is NOT a reason for failure at this point in time and the next set of MOT regulations updates could start to apply CAT/DPF removal test criteria. As was/is with the the Petrol CAT tests these are vehicle PRODUCTION based date criteria and NOT MOT regs based dates. This means that MOT (say) 2015 regs can taget vehicles manufactured after 2010 BUT ONLY with test levels applicable to Euro X emissions levels applicable at the time.
From the UK MOT Inspection Manual
7.1 Exhaust System 7.1 - page 1
The M.O.T. Inspection Manual Issue Date 01 January 2012
Information
-------------
The overall security of the exhaust system
should be assessed; one or more exhaust
mountings missing may not be a Reason for
Rejection.
A durable repair to an exhaust system which
effectively prevents leaks is acceptable providing
the system is structurally sound.
A minor exhaust leak from, for example, a
connection joint or a pin hole, is not a Reason for
Rejection.
Method of Inspection
-----------------------
1. Check the security of the exhaust system.
2. With the engine running, check the exhaust
system for leaks.
3. On vehicles that qualify for a full cat emissions
test, check the presence of the catalytic
converter.
4. During all parts of the emissions test relevant
for the vehicle, assess subjectively the
effectiveness of the silencer in reducing exhaust
noise.
Note: For vehicles not subject to an emissions
test, the engine should be revved to around
2500rpm or approximately half maximum
engine speed if this is lower.
5. On Class 5 vehicles only, check that the
exhaust tailpipe is positioned so it is unlikely
that fumes will enter the driver’s or passenger
area.
Reason for Rejection
-----------------------
1. An exhaust system not adequately supported.
2. A major leak of exhaust gases from any part of
the system.
3. A catalytic converter missing where one was
fitted as standard
4. A silencer in such condition, or of such a type,
that the noise emitted from the vehicle is clearly
unreasonably above the level expected from a
similar vehicle with a standard silencer in
average condition.
5. An exhaust tailpipe positioned so that fumes
are likely to enter the driver’s or passenger
area.
See below. Missing CAT is a failure, but only "On vehicles that qualify for a full cat emissions".
The catalyst test is part of the MOT test for most spark ignition petrol engined vehicles with four or more wheels first used on and after 1 August 1992.
Compression Ignition engines are currently only subject to a SMOKE test. Now most modern Euro IV diesels have DPFs (diesel particulate filters) and some/all Euro V have Catalysing DPFs (as I understand it). So on a Euro IV diesel DPF removal is not an MOT failure YET. On a Euro V whilst CAT/DPF removal is NOT a reason for failure at this point in time and the next set of MOT regulations updates could start to apply CAT/DPF removal test criteria. As was/is with the the Petrol CAT tests these are vehicle PRODUCTION based date criteria and NOT MOT regs based dates. This means that MOT (say) 2015 regs can taget vehicles manufactured after 2010 BUT ONLY with test levels applicable to Euro X emissions levels applicable at the time.
From the UK MOT Inspection Manual
7.1 Exhaust System 7.1 - page 1
The M.O.T. Inspection Manual Issue Date 01 January 2012
Information
-------------
The overall security of the exhaust system
should be assessed; one or more exhaust
mountings missing may not be a Reason for
Rejection.
A durable repair to an exhaust system which
effectively prevents leaks is acceptable providing
the system is structurally sound.
A minor exhaust leak from, for example, a
connection joint or a pin hole, is not a Reason for
Rejection.
Method of Inspection
-----------------------
1. Check the security of the exhaust system.
2. With the engine running, check the exhaust
system for leaks.
3. On vehicles that qualify for a full cat emissions
test, check the presence of the catalytic
converter.
4. During all parts of the emissions test relevant
for the vehicle, assess subjectively the
effectiveness of the silencer in reducing exhaust
noise.
Note: For vehicles not subject to an emissions
test, the engine should be revved to around
2500rpm or approximately half maximum
engine speed if this is lower.
5. On Class 5 vehicles only, check that the
exhaust tailpipe is positioned so it is unlikely
that fumes will enter the driver’s or passenger
area.
Reason for Rejection
-----------------------
1. An exhaust system not adequately supported.
2. A major leak of exhaust gases from any part of
the system.
3. A catalytic converter missing where one was
fitted as standard
4. A silencer in such condition, or of such a type,
that the noise emitted from the vehicle is clearly
unreasonably above the level expected from a
similar vehicle with a standard silencer in
average condition.
5. An exhaust tailpipe positioned so that fumes
are likely to enter the driver’s or passenger
area.
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