Discussion
They work by absorbing particulates when the engine is cold or running at relatively low loads (such as most town driving). Then at constantly higher loads (and in theory when away from centres of population) they heat up and burn off the particulates; this is usually called "regenerating". If you never get them into the state they require for regeneration, they will eventually clog up and fail.
So the question isn't how much town driving you do, it's how frequently you do other types of driving. If you do one 20 mile round trip every week at motorways speeds, it'll be fine even if the rest of your driving is all around town. If you go months on end never getting above 30mph, it'll probably eventually fail.
So the question isn't how much town driving you do, it's how frequently you do other types of driving. If you do one 20 mile round trip every week at motorways speeds, it'll be fine even if the rest of your driving is all around town. If you go months on end never getting above 30mph, it'll probably eventually fail.
I have had a VW 1.6TDI for the last 3 years, It has a DPF Filter. It regenerates once a week or 300 miles. Takes about 20 Minutes of driving until it finishes, I do 10000 miles a year too and 70% town driving.
Personally I would recommend looking at a Petrol version, you might be okay but not worth the hassle. The DPF light on mine comes on quite often in the colder months when the engine never warms up properly. It also has a habit of dumping diesel into its sump due to the frequent DPF regenerations, meaning oil changes are needed every 6 months/ 5000 Miles.
Get a Petrol one, but not a 1.8TFSI as I think they have their fair share of issues.
Personally I would recommend looking at a Petrol version, you might be okay but not worth the hassle. The DPF light on mine comes on quite often in the colder months when the engine never warms up properly. It also has a habit of dumping diesel into its sump due to the frequent DPF regenerations, meaning oil changes are needed every 6 months/ 5000 Miles.
Get a Petrol one, but not a 1.8TFSI as I think they have their fair share of issues.
Yes, the 1.4 petrol is a well proven engine.
How old is the diesel A3 you're looking at?
If it's the older PD (Pumpe Duse) engine then these don't get on as well with their DPF's. The later CR (Common Rail) engines have a catalyst in front of the DPF helping it to get hot and burn off the soot when your driving style alone doesn't, so are much more reliable.
How old is the diesel A3 you're looking at?
If it's the older PD (Pumpe Duse) engine then these don't get on as well with their DPF's. The later CR (Common Rail) engines have a catalyst in front of the DPF helping it to get hot and burn off the soot when your driving style alone doesn't, so are much more reliable.
Craig991 said:
Thanks for the replies but anyone know if the 1.4 tfsi is any good?
If you mean the more recent turbocharged unit, it's decent enough. If you mean the earlier twin-charged engine, I'd avoid it (not sure if that was used int he A3 though).VW have had a lot of different engines with the same high-level identifier so we really need to know the age of car you're considering to know.
Craig991 said:
I saw 2 which was a 2013 & 2014 13 was a s line & the 14 was a s line quattro
That's the turbocharged unit then. I think they're decent enough - not very fast (I think it's only 120bhp and the A4 isn't a light car) but capable enough and with enough torque to be pretty effortless to drive. I think that era gave pretty decent economy (of the order of 45-50mpg in mixed driving), although I have no personal experience. Subaru Australia tell it like it is.
They must have had too many complaints about DPF failures.
https://www.subaru.com.au/car-advice/benefits-of-a...
Benefits Of A Diesel Engine
Diesel cars justifiably have a great reputation for excellent fuel economy and low impact on the environment. This essentially is a result of the diesel operating cycle being thermodynamically more efficient than the petrol engine. Put more simply, more energy is converted into useful work and less energy in the form of heat which is transmitted to the cooling system and subsequently to the atmosphere. This means that a diesel engine in a similar sized vehicle is much more fuel efficient in terms of kilometres per litre than a petrol engine.
This characteristic of higher thermodynamic efficiency with less heat going into the cooling system means that a diesel engine takes longer to reach the most efficient operating temperature and requires a higher engine load to maintain that temperature. This means that a diesel engine is more suited to longer distance driving at higher vehicle speeds or loads. If a diesel engine is not driven at its optimum operating temperature then its fuel and environmental efficiency significantly deteriorates. In a nutshell, the diesel engine in a passenger car is not suitable for short trips at low loads in a city environment, i.e. one or two passengers travelling to the shops and back.
One of the reasons why a diesel engine is more fuel-efficient is because it operates at higher pressures than a petrol engine. This means that structurally the engine needs to be significantly stronger than a petrol engine. This is why a Boxer engine is particularly suitable for use as a diesel engine, because the engine crankshaft, that carries the majority of engine load and pressure, is provided with a high level of support by being sandwiched between the two halves of the crankcase. Never the less, even a Boxer diesel engine structure and its fuel delivery system that injects fuel directly into the high pressure combustion chamber needs to be manufactured with higher levels of strength and durability. This means that a diesel engine is typically approximately $3000 more expensive than a petrol engine and therefore to recover this increased capital cost longer driving with higher kilometres per year are required.
Fuel savings, however, are significant, with fuel efficiency typically being 25-35% better than a petrol engine vehicle and, given sufficient use (kilometres), the increased capital cost can be recovered with significant savings made. As an example, let’s look at the model year 2012 Forester X and 2.0D, using the published combined cycle fuel consumption figures of 9.3 litres per 100 km and 6.0 litres per 100km respectively. At 25,000km per year it will take 3 years to cover the increased purchase price of the diesel engine at a 2011-12 national average fuel price of 144.1 cents per litre for petrol and 150.5 cents for diesel. After this has been achieved your fuel bills will be 33% cheaper.
Historically the diesel engine was also considered to be lacking power and driveability in a passenger car, however the modern passenger diesel engine is almost indistinguishable from the performance of a petrol engine. This is due to advances in electronics and computer management systems that have enabled more precise control of the combustion process and the adoption of turbochargers to increase the power output and responsiveness of the diesel engine while retaining its advantages of fuel efficiency and environmental performance.
As stated in the introduction, a diesel engine is also generally considered to be more environmentally friendly than a petrol engine. This is very true in terms of hydrocarbon (HC), and carbon monoxide (CO) emissions that are approximately 38% and 60% respectively lower than a petrol engine. However, a diesel engine also produces significantly more particulate emission (black soot) under certain operating conditions such as cold start, acceleration, high load and when driven at less that full operating temperature. These soot particles are microscopically small (0.09mm) which the human respiratory system is unable able to filter so they can enter the lungs and pose a serious health hazard.
This is why the modern diesel engine uses a special filter to capture 95% of these soot particles. This filter known as a Diesel Particulate Filter (DPF) automatically cleans itself by burning the captured soot particles. To be able to do this, however, its temperature needs to be in the region of 550°C to 700°C. Urban driving at light throttle results in exhaust temperatures typically in the range of 150 to 200°C, so with this type of continual driving the DPF is unable to clean itself and it can become blocked. To help alleviate this situation the DPF is subjected to computer controlled regenerative processes that raise the combustion temperature to force drive the DPF burning process. However, these regenerative processes also require an engine operating temperature that is not sustainable in a continued urban driving environment. When this situation occurs the driver is warned via a warning light to drive the vehicle at a higher speed & load to raise the exhaust temperature so the DPF can burn the soot particles. Failure to do so will ultimately result in the DPF becoming blocked. If this happens it will possibly be necessary to replace the DPF at a significant cost (thousands of dollars).
So again it is clear that a diesel engine vehicle requires a driving style and method of use that is only suitable for longer distances and higher loads! If this is your particular method of use and you travel high kilometres then a diesel engine vehicle is particularly suitable due to the fuel efficiency and environmental performance, but if you normally travel short distances then a petrol engine is a better choice.
For the first time, Subaru has mated a LineartronicTM CVT automatic gearbox to its turbocharged horizontally-opposed Boxer diesel engine, resulting in an incredibly capable AWD package. This is exclusively available on the Subaru Outback Diesel models. Click here to discover the Outback Diesel range.
© 2016 - Subaru (Aust) Pty Limited
They must have had too many complaints about DPF failures.
https://www.subaru.com.au/car-advice/benefits-of-a...
Benefits Of A Diesel Engine
Diesel cars justifiably have a great reputation for excellent fuel economy and low impact on the environment. This essentially is a result of the diesel operating cycle being thermodynamically more efficient than the petrol engine. Put more simply, more energy is converted into useful work and less energy in the form of heat which is transmitted to the cooling system and subsequently to the atmosphere. This means that a diesel engine in a similar sized vehicle is much more fuel efficient in terms of kilometres per litre than a petrol engine.
This characteristic of higher thermodynamic efficiency with less heat going into the cooling system means that a diesel engine takes longer to reach the most efficient operating temperature and requires a higher engine load to maintain that temperature. This means that a diesel engine is more suited to longer distance driving at higher vehicle speeds or loads. If a diesel engine is not driven at its optimum operating temperature then its fuel and environmental efficiency significantly deteriorates. In a nutshell, the diesel engine in a passenger car is not suitable for short trips at low loads in a city environment, i.e. one or two passengers travelling to the shops and back.
One of the reasons why a diesel engine is more fuel-efficient is because it operates at higher pressures than a petrol engine. This means that structurally the engine needs to be significantly stronger than a petrol engine. This is why a Boxer engine is particularly suitable for use as a diesel engine, because the engine crankshaft, that carries the majority of engine load and pressure, is provided with a high level of support by being sandwiched between the two halves of the crankcase. Never the less, even a Boxer diesel engine structure and its fuel delivery system that injects fuel directly into the high pressure combustion chamber needs to be manufactured with higher levels of strength and durability. This means that a diesel engine is typically approximately $3000 more expensive than a petrol engine and therefore to recover this increased capital cost longer driving with higher kilometres per year are required.
Fuel savings, however, are significant, with fuel efficiency typically being 25-35% better than a petrol engine vehicle and, given sufficient use (kilometres), the increased capital cost can be recovered with significant savings made. As an example, let’s look at the model year 2012 Forester X and 2.0D, using the published combined cycle fuel consumption figures of 9.3 litres per 100 km and 6.0 litres per 100km respectively. At 25,000km per year it will take 3 years to cover the increased purchase price of the diesel engine at a 2011-12 national average fuel price of 144.1 cents per litre for petrol and 150.5 cents for diesel. After this has been achieved your fuel bills will be 33% cheaper.
Historically the diesel engine was also considered to be lacking power and driveability in a passenger car, however the modern passenger diesel engine is almost indistinguishable from the performance of a petrol engine. This is due to advances in electronics and computer management systems that have enabled more precise control of the combustion process and the adoption of turbochargers to increase the power output and responsiveness of the diesel engine while retaining its advantages of fuel efficiency and environmental performance.
As stated in the introduction, a diesel engine is also generally considered to be more environmentally friendly than a petrol engine. This is very true in terms of hydrocarbon (HC), and carbon monoxide (CO) emissions that are approximately 38% and 60% respectively lower than a petrol engine. However, a diesel engine also produces significantly more particulate emission (black soot) under certain operating conditions such as cold start, acceleration, high load and when driven at less that full operating temperature. These soot particles are microscopically small (0.09mm) which the human respiratory system is unable able to filter so they can enter the lungs and pose a serious health hazard.
This is why the modern diesel engine uses a special filter to capture 95% of these soot particles. This filter known as a Diesel Particulate Filter (DPF) automatically cleans itself by burning the captured soot particles. To be able to do this, however, its temperature needs to be in the region of 550°C to 700°C. Urban driving at light throttle results in exhaust temperatures typically in the range of 150 to 200°C, so with this type of continual driving the DPF is unable to clean itself and it can become blocked. To help alleviate this situation the DPF is subjected to computer controlled regenerative processes that raise the combustion temperature to force drive the DPF burning process. However, these regenerative processes also require an engine operating temperature that is not sustainable in a continued urban driving environment. When this situation occurs the driver is warned via a warning light to drive the vehicle at a higher speed & load to raise the exhaust temperature so the DPF can burn the soot particles. Failure to do so will ultimately result in the DPF becoming blocked. If this happens it will possibly be necessary to replace the DPF at a significant cost (thousands of dollars).
So again it is clear that a diesel engine vehicle requires a driving style and method of use that is only suitable for longer distances and higher loads! If this is your particular method of use and you travel high kilometres then a diesel engine vehicle is particularly suitable due to the fuel efficiency and environmental performance, but if you normally travel short distances then a petrol engine is a better choice.
For the first time, Subaru has mated a LineartronicTM CVT automatic gearbox to its turbocharged horizontally-opposed Boxer diesel engine, resulting in an incredibly capable AWD package. This is exclusively available on the Subaru Outback Diesel models. Click here to discover the Outback Diesel range.
© 2016 - Subaru (Aust) Pty Limited
I had a 1.8 tfsi A3, loved it from a performance point of view. It would do over 40mpg on a run, about 30 knocking about.
Mine was from 2009, spent quite a bit on it but it never broke down, I replaced the water pump with the upgraded one, and a thermostat, everything else was just maintenance.
Mine was from 2009, spent quite a bit on it but it never broke down, I replaced the water pump with the upgraded one, and a thermostat, everything else was just maintenance.
Craig991 said:
Thanks for the replies but anyone know if the 1.4 tfsi is any good?
We have a 1.6TDI (same engine) in a SEAT Altea and the wife now only does 10k a year (was more, with longer runs) and has started to have issues, not with the dpf but with the EGR - had to have it replaced and was £829 from a SEAT garage. The EGR itself is about £300 and then five or six hours labour is the book for it. My local indy didnt want to touch it. Not had any DPF issues with it yet, but do expect to.
Anyway, Father in law has an A3 1.4 TFSI and I have driven the SEAT Leon with the 1.5 version of it - a great engine TBH, even in DSG version (on the Leon). Fuel economy is good as long as not thrashing it as it has the active cylinder technology and drops two cylinders when not under load. Even at motorway speeds it can drop into 2Cyl mode.
I got a reported 50mpg in the (hire) Leon DSG last week on a 45mile run - the fuel computer reads slightly over probably but I wasnt even trying for fuel economy so 50 - 55 should be attainable once the car is run in.
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