MOT Assistance
Discussion
Had my car in for its first MOT this morning. As I half expected, it failed on emissions.
My car is running a tweaked LS3 with no cats, I didn't build it so I don't have all the information, but as I understand it, it was originally built with a cat exhaust then swapped post IVA for more power.
Has anyone had experience with retro fitting cats into an exhaust? Any alternative suggestions?
Also, this is one for the factory I think, the headlamps failed as they tick up the wrong way. Are the headlamp units switchable for LHD/RHD or do I have the wrong units? If they are wrong, how simple will it be to swap the units to the correct ones?
My car is running a tweaked LS3 with no cats, I didn't build it so I don't have all the information, but as I understand it, it was originally built with a cat exhaust then swapped post IVA for more power.
Has anyone had experience with retro fitting cats into an exhaust? Any alternative suggestions?
Also, this is one for the factory I think, the headlamps failed as they tick up the wrong way. Are the headlamp units switchable for LHD/RHD or do I have the wrong units? If they are wrong, how simple will it be to swap the units to the correct ones?
The best way out of this (if you have room) is to fit cats with Vee band connectors so that you can swap them out as needed.
An example (not Chevy) here:
http://www.evolveautomotive.com/e60-m5_844/perform...
Someone like Hayward & Scott would be a good bet to fabricate something to fit an awkward shaped system.
http://www.haywardandscott.com/
It would be handy to have a switchable map for cat and non-cat use or at least a flash-able map for use once a year
An example (not Chevy) here:
http://www.evolveautomotive.com/e60-m5_844/perform...
Someone like Hayward & Scott would be a good bet to fabricate something to fit an awkward shaped system.
http://www.haywardandscott.com/
It would be handy to have a switchable map for cat and non-cat use or at least a flash-able map for use once a year
tjlees said:
I've had two MOTs and though I know it will pass emissions, the guy has not used the probe at all stating that it's a kit car and there is no emission rating on the V5.
Can anyone tell me what the rules are with ultima cars (2010) having an LS7?
Can anyone tell me what the rules are with ultima cars (2010) having an LS7?
Normally it is a case of what age the engine is when the car is built i.e. if it is an old SBC then the car will have to pass a visible smoke test.
If it was BUILT with an LS series motor you will need to pass emissions at the age point when the engine was built.
If you have an Ultima with a REPLACEMENT LS where the original was SBC the requirement will not show on the log book and will only need to pass the smoke test.
Simples...
There are four different sets of petrol exhaust emissions standards which can apply, and the Ultima, or any other car coming in for its MOT, needs to pass one of them. The starting point as to which standard should apply is the date of registration of the vehicle, so in your Ultima's case the most modern set of emissions standards apply. If a vehicle presenter can show written proof to the tester that an earlier (or replacement) engine has been fitted, then the tester would normally apply an earlier (less stringent) emissions test. In the case of a Pre-71 engine such as a GEN1 small block Chevrolet on a Holley, that could amount to a Visual test only (where emissions are not even measured by machine) and its is left down to the discretion of a tester whether he can see any blue or white smoke visible at a specified fast idle.
Applying the latest test needed for your Ultima, the vehicle is asked to pass a Basic Emissions Test (BET), and most modern vehicles need a working cat/lambdas, but usually do. If the vehicle is unable to pass BET, then there is a follow up with a second procedure where we look on the Vehicle Database and compare the emissions seen with that which is recorded on the database, and pass or fail accordingly.
I can tell you there is no Ultima data registered on the database, so again there is a "not on the database" MOT third procedure which has to be followed, and just because an Ultima is a "kit car" it is no different to any other car, so you can't just pass it because there's no emissions data available as someone else has suggested.
In practise you really need to find a garage with an experienced tester who knows how to, and will apply the proper emissions test to the car, and this usually means someone older, sensible and sympathetic to the car (yes, this IS an Ageist remark!).
We see quite a few high performance vehicles, and I can say that it is perfectly possible to get a modern fuel injected engine with no cats/lambdas through emissions if its mapped really precisely. Without getting in too deep, its simply a function of getting a 14.7:1 air/fuel ratio at constant part-throttle load at 2500rpm. That's all your lambdas are doing for you electronically on loop.
Switchable map on your ECU would do it...of course, having once passed an MOT you would only ever switch back and use the "other" performance map for your track days, wouldn't you?
There are four different sets of petrol exhaust emissions standards which can apply, and the Ultima, or any other car coming in for its MOT, needs to pass one of them. The starting point as to which standard should apply is the date of registration of the vehicle, so in your Ultima's case the most modern set of emissions standards apply. If a vehicle presenter can show written proof to the tester that an earlier (or replacement) engine has been fitted, then the tester would normally apply an earlier (less stringent) emissions test. In the case of a Pre-71 engine such as a GEN1 small block Chevrolet on a Holley, that could amount to a Visual test only (where emissions are not even measured by machine) and its is left down to the discretion of a tester whether he can see any blue or white smoke visible at a specified fast idle.
Applying the latest test needed for your Ultima, the vehicle is asked to pass a Basic Emissions Test (BET), and most modern vehicles need a working cat/lambdas, but usually do. If the vehicle is unable to pass BET, then there is a follow up with a second procedure where we look on the Vehicle Database and compare the emissions seen with that which is recorded on the database, and pass or fail accordingly.
I can tell you there is no Ultima data registered on the database, so again there is a "not on the database" MOT third procedure which has to be followed, and just because an Ultima is a "kit car" it is no different to any other car, so you can't just pass it because there's no emissions data available as someone else has suggested.
In practise you really need to find a garage with an experienced tester who knows how to, and will apply the proper emissions test to the car, and this usually means someone older, sensible and sympathetic to the car (yes, this IS an Ageist remark!).
We see quite a few high performance vehicles, and I can say that it is perfectly possible to get a modern fuel injected engine with no cats/lambdas through emissions if its mapped really precisely. Without getting in too deep, its simply a function of getting a 14.7:1 air/fuel ratio at constant part-throttle load at 2500rpm. That's all your lambdas are doing for you electronically on loop.
Switchable map on your ECU would do it...of course, having once passed an MOT you would only ever switch back and use the "other" performance map for your track days, wouldn't you?
Thanks for the replies (particularly GT5594).
The car is registered 2012 with an LS3 so there is no getting around the fact that the car needs to pass the full emissions test. The tester was fully aware of the regulations and knew that if the engine was pre '92 then a much less strict measure was due, unfortunately the engine is way past 1992!
My problem is that the engine in its current tune will not pass emissions, I understand from the previous owner that it did pass when fitted with exhausts with cats, and I am picking them up on Saturday in the hope that fitting these will be enough.
I am a little concerned, however, that this will not do the trick as I am currently running something like 5% not 0.7%(?). Backed up by the fact that the back of the car is covered in soot! I do know that the car has been "tuned" post SVA although I'm not sure what was done and I cannot find the garage that was supposed to have done the work (LS Performance or similar near London?). Does anyone know if it is possible to map the Partsworld LS ECU and who can do this otherwise I have a nasty feeling that the previous owner may have been ripped off and "tuning" consisted of upping the fuel pressure (which I can easily verify with a little time in the garage).
The car is registered 2012 with an LS3 so there is no getting around the fact that the car needs to pass the full emissions test. The tester was fully aware of the regulations and knew that if the engine was pre '92 then a much less strict measure was due, unfortunately the engine is way past 1992!
My problem is that the engine in its current tune will not pass emissions, I understand from the previous owner that it did pass when fitted with exhausts with cats, and I am picking them up on Saturday in the hope that fitting these will be enough.
I am a little concerned, however, that this will not do the trick as I am currently running something like 5% not 0.7%(?). Backed up by the fact that the back of the car is covered in soot! I do know that the car has been "tuned" post SVA although I'm not sure what was done and I cannot find the garage that was supposed to have done the work (LS Performance or similar near London?). Does anyone know if it is possible to map the Partsworld LS ECU and who can do this otherwise I have a nasty feeling that the previous owner may have been ripped off and "tuning" consisted of upping the fuel pressure (which I can easily verify with a little time in the garage).
Lsv8 power may have mapped it?
There is a general lack of good LS mappers around unfortunately. I suspect some do little more than take a generic map from hp tuners or efilive forum and tweak them as little as possible.
DHGTR had a good result from a place Birmingham way, but they only map weekdays, so if you're self employed that may cause an issue.
I believe AB can do a good job for you if they're not too far.
Have you been in touch with the original builder?
Would adjusting the fuel regulator help?
There is a general lack of good LS mappers around unfortunately. I suspect some do little more than take a generic map from hp tuners or efilive forum and tweak them as little as possible.
DHGTR had a good result from a place Birmingham way, but they only map weekdays, so if you're self employed that may cause an issue.
I believe AB can do a good job for you if they're not too far.
Have you been in touch with the original builder?
Would adjusting the fuel regulator help?
gt5594 said:
Simples...
I can tell you there is no Ultima data registered on the database, so again there is a "not on the database" MOT third procedure which has to be followed, and just because an Ultima is a "kit car" it is no different to any other car, so you can't just pass it because there's no emissions data available as someone else has suggested.
So what is the third procedure?I can tell you there is no Ultima data registered on the database, so again there is a "not on the database" MOT third procedure which has to be followed, and just because an Ultima is a "kit car" it is no different to any other car, so you can't just pass it because there's no emissions data available as someone else has suggested.
Since you asked...
When the car fails the Basic Emissions Test (BET) we consult the 18th Edition of In Service Exhaust Emissions Standards for Road Vehicles, which is a database against which the car's emissions are to be compared. Download it if you are interested from here:
https://www.gov.uk/government/uploads/system/uploa...
Most garages have the above document loaded into their emissions machines to save continuous look-ups
If the car is not listed in this database (which in the case of Ultima it is not) then we are required to check the age of the vehicle to see if it should be running with a CAT, and then do extended an CAT test However with no information to measure the emissions against, my machine has no alternative but to default to a Pre-Cat test, which is less stringent. In practice there is nothing else we can do as a tester, as if the vehicle is presented for test without cats (and we believe it should have them), and the software installed on the calibrated emissions tester throws up a pre-cat test, then in practice we would simply mark an "Advise" on the certificate, saying the vehicle was "presented without Cats fitted so a Pre-Cat test was done". Ultimas are rarely seen in MOT stations so the poor tester can not be expected to know the full specification of the car, so must follow his limited procedures
This is far from ideal.
If a DVSA authorised vehicle examiner were to read this, I would probably get shot down in flames, but realistically the MOT system has to cater for a volume of approaching 30 million tests per year, and the number of Ultimas running around the UK and requiring MOT is proportionately tiny.
This is obviously a grey area, and so I would advise the correct thing to do would be for the Ultima owner to approach DVSA directly if they were uncertain as to how a non-cat car could meet MOT emissions standards. DVSA would then decide on the issue and send clarification via a Special Notice to every tester in the land, but being pragmatic, DVSA are extremely busy trying to roll out the new computerised MOT system, which involves every VTS upgrading to the new system by September 2015, and there may be other pressures which prevent clarification for the foreseeable future.
Apologies for being "corporate"...
When the car fails the Basic Emissions Test (BET) we consult the 18th Edition of In Service Exhaust Emissions Standards for Road Vehicles, which is a database against which the car's emissions are to be compared. Download it if you are interested from here:
https://www.gov.uk/government/uploads/system/uploa...
Most garages have the above document loaded into their emissions machines to save continuous look-ups
If the car is not listed in this database (which in the case of Ultima it is not) then we are required to check the age of the vehicle to see if it should be running with a CAT, and then do extended an CAT test However with no information to measure the emissions against, my machine has no alternative but to default to a Pre-Cat test, which is less stringent. In practice there is nothing else we can do as a tester, as if the vehicle is presented for test without cats (and we believe it should have them), and the software installed on the calibrated emissions tester throws up a pre-cat test, then in practice we would simply mark an "Advise" on the certificate, saying the vehicle was "presented without Cats fitted so a Pre-Cat test was done". Ultimas are rarely seen in MOT stations so the poor tester can not be expected to know the full specification of the car, so must follow his limited procedures
This is far from ideal.
If a DVSA authorised vehicle examiner were to read this, I would probably get shot down in flames, but realistically the MOT system has to cater for a volume of approaching 30 million tests per year, and the number of Ultimas running around the UK and requiring MOT is proportionately tiny.
This is obviously a grey area, and so I would advise the correct thing to do would be for the Ultima owner to approach DVSA directly if they were uncertain as to how a non-cat car could meet MOT emissions standards. DVSA would then decide on the issue and send clarification via a Special Notice to every tester in the land, but being pragmatic, DVSA are extremely busy trying to roll out the new computerised MOT system, which involves every VTS upgrading to the new system by September 2015, and there may be other pressures which prevent clarification for the foreseeable future.
Apologies for being "corporate"...
If a vehicle was presented with some evidence to a VTS showing that an engine was fitted from a pre-August 1992 car then the emissions test carried out would be pre-cat, i.e. less than 3.5% CO and less than 1200 ppm. Of course your car would still need a little work to get there...
The average VTS tester would not know one end of a chevy V8 from another, and certainly not a Gen2 from a Gen4 sbc, and is forced to give the benefit of doubt to the vehicle presenter.
Whilst a 5% CO reading is absolutely great for power. if you do decide to fit cats, unless you get the engine properly remapped, you should be aware that one of the very best ingredients for burning out catalytic converters is an excessively rich fuel mixture. I have seen this happen within 200 miles...
So pragmatically, either have your car tested as if has been fitted with a Pre 1 August 1992 engine, or find someone to fit and fabricate a pair of cats, pre- and post lambdas and skilled at remapping, and all the attendant cost.
That's your simple choice I'm afraid. Beats going all round the houses, though!
The average VTS tester would not know one end of a chevy V8 from another, and certainly not a Gen2 from a Gen4 sbc, and is forced to give the benefit of doubt to the vehicle presenter.
Whilst a 5% CO reading is absolutely great for power. if you do decide to fit cats, unless you get the engine properly remapped, you should be aware that one of the very best ingredients for burning out catalytic converters is an excessively rich fuel mixture. I have seen this happen within 200 miles...
So pragmatically, either have your car tested as if has been fitted with a Pre 1 August 1992 engine, or find someone to fit and fabricate a pair of cats, pre- and post lambdas and skilled at remapping, and all the attendant cost.
That's your simple choice I'm afraid. Beats going all round the houses, though!
gt5594 said:
If a vehicle was presented with some evidence to a VTS showing that an engine was fitted from a pre-August 1992 car then the emissions test carried out would be pre-cat, i.e. less than 3.5% CO and less than 1200 ppm. Of course your car would still need a little work to get there...
The average VTS tester would not know one end of a chevy V8 from another, and certainly not a Gen2 from a Gen4 sbc, and is forced to give the benefit of doubt to the vehicle presenter.
Whilst a 5% CO reading is absolutely great for power. if you do decide to fit cats, unless you get the engine properly remapped, you should be aware that one of the very best ingredients for burning out catalytic converters is an excessively rich fuel mixture. I have seen this happen within 200 miles...
So pragmatically, either have your car tested as if has been fitted with a Pre 1 August 1992 engine, or find someone to fit and fabricate a pair of cats, pre- and post lambdas and skilled at remapping, and all the attendant cost.
That's your simple choice I'm afraid. Beats going all round the houses, though!
Thanks for that starting to understand. What about lambda? Does that more or less have to sit at 1?The average VTS tester would not know one end of a chevy V8 from another, and certainly not a Gen2 from a Gen4 sbc, and is forced to give the benefit of doubt to the vehicle presenter.
Whilst a 5% CO reading is absolutely great for power. if you do decide to fit cats, unless you get the engine properly remapped, you should be aware that one of the very best ingredients for burning out catalytic converters is an excessively rich fuel mixture. I have seen this happen within 200 miles...
So pragmatically, either have your car tested as if has been fitted with a Pre 1 August 1992 engine, or find someone to fit and fabricate a pair of cats, pre- and post lambdas and skilled at remapping, and all the attendant cost.
That's your simple choice I'm afraid. Beats going all round the houses, though!
Yes
Lambda 1 = 14.7 to 1 air fuel, or the point at which we get the "cleanest" output to the cats. On a 1992 onwards MOT emissions test we are looking for a lambda of 1, plus or minus 3%, i.e. lambda 0.97 to 1.03. which is a air/fuel mix of between 14.3 to 1 (slightly rich) and 15.1 to 1 (slightly lean). Both lambdas self-learn so when the front one is working we get one up-down adjustment per second (1 hz output) the cat works its magic, then the second lambda says yes, that's OK, and so the second output on an oscilloscope is a flattish line. Both lambdas are checking for the presence of minute amounts of oxygen across a tip, and produce a minute alteration which is fed and processed by an ECU. It's a closed loop system. Presence of minute amounts of oxygen is telling the ECU the fuel burn is not quite clean, hence "adjust fuel", and when there's no spare oxygen around, "stop adjusting fuel". The ECU compares the outputs from both Lamdas, and when they are both similar it knows the cat is not working as the back lambda is trying to adjust fuel mix, and this is a signal to put an engine management or emissions warning light on the dashboard of the Eurobox.
When we tune for best power we often end up with a lambda of 0.85 t0 0.87 (or about 13-15% rich on fuel) and this typically produces a CO reading of around 7%. CO emissions on a car that will pass a modern emissions MOT test are typically 0.00% or zero CO with a properly working cat system including working lambdas.
So if you have a CO reading on this engine of 5%, that's a great indication the fuel mix is running around 13 to 1, and producing plenty of power.
Unfortunately, when you put cats on this engine, working lambdas and map accordingly you will inevitably notice a difference in torque and power outputs of maybe up to 12-15%, owing to the much leaner mixture, and a restriction in the flow through the exhausts.
Hope this helps your understanding. Depending on your point of view catalytic converters are the Devil's invention/Saviour of the Planet, but I get to problem-solve these systems regularly, so I thought I could help with a few words here.
Lambda 1 = 14.7 to 1 air fuel, or the point at which we get the "cleanest" output to the cats. On a 1992 onwards MOT emissions test we are looking for a lambda of 1, plus or minus 3%, i.e. lambda 0.97 to 1.03. which is a air/fuel mix of between 14.3 to 1 (slightly rich) and 15.1 to 1 (slightly lean). Both lambdas self-learn so when the front one is working we get one up-down adjustment per second (1 hz output) the cat works its magic, then the second lambda says yes, that's OK, and so the second output on an oscilloscope is a flattish line. Both lambdas are checking for the presence of minute amounts of oxygen across a tip, and produce a minute alteration which is fed and processed by an ECU. It's a closed loop system. Presence of minute amounts of oxygen is telling the ECU the fuel burn is not quite clean, hence "adjust fuel", and when there's no spare oxygen around, "stop adjusting fuel". The ECU compares the outputs from both Lamdas, and when they are both similar it knows the cat is not working as the back lambda is trying to adjust fuel mix, and this is a signal to put an engine management or emissions warning light on the dashboard of the Eurobox.
When we tune for best power we often end up with a lambda of 0.85 t0 0.87 (or about 13-15% rich on fuel) and this typically produces a CO reading of around 7%. CO emissions on a car that will pass a modern emissions MOT test are typically 0.00% or zero CO with a properly working cat system including working lambdas.
So if you have a CO reading on this engine of 5%, that's a great indication the fuel mix is running around 13 to 1, and producing plenty of power.
Unfortunately, when you put cats on this engine, working lambdas and map accordingly you will inevitably notice a difference in torque and power outputs of maybe up to 12-15%, owing to the much leaner mixture, and a restriction in the flow through the exhausts.
Hope this helps your understanding. Depending on your point of view catalytic converters are the Devil's invention/Saviour of the Planet, but I get to problem-solve these systems regularly, so I thought I could help with a few words here.
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