VW Golf active cylinder technology
Discussion
When VW announced this engine in the Polo Blue motion GT and then the Golf it seemed to me as someone who ideally would like to move away from disiesal for an everyday car an almost perfect blend; 140bhp, 0-60 in 8 seconds & 58.9mpg (in the Golf). A year or so on I'm intrigued if anyone who has one, in either the Golf or the myriad other VAG products gets anywhere near the claimed MPG?
Reading a few threads this year a number of people noted that they've got nowhere near the claimed figures on diesels (not surprising really) but have for petrols, so is this the case with this engine?
Just intrigued in any real life examples.
Cheers
Reading a few threads this year a number of people noted that they've got nowhere near the claimed figures on diesels (not surprising really) but have for petrols, so is this the case with this engine?
Just intrigued in any real life examples.
Cheers
The reason people are not getting close to the claimed economy figures is because the higher the economy, the harder it is to achive. Because economy in Miles PER gallon is the reciprocal of the fuel consumed, the distance travelled per gallon is proportionally higher.
By way of illustration, take two cars, one that does 25mpg, and one that does 50mpg. Both drive for 100miles.
Car A will have used 4 gallons (4=100/25)
Car B will have used 2 gallons (2=100/50)
Lets say both cars are poorly driven, and the drivers drive in such a fashion to use and extra gallon of fuel(an extreme example, used to illustrate the point).
As a result Car A consumption falls to 20mpg (=100/5) a drop of 5mpg
But Car B falls to 33mpg (=100/3) a drop of 17mpg.
This illustrates that is becomes proportionally more difficult to achieve the claimed fuel economy as that economy figure increases. Even though both drivers have "wasted" the same volume of fuel (1 gallon)
In extremis, a car that could travel from london to scotland on a single drop of fuel, could actually return zero mpg if you accidentally spilled that drop of fuel on the petrol station floor by mistake!!!
Modern cars are both highly efficient, but also high powered. As such, they can consume a large quanity of fuel very quickly if driven poorly. (most modern cars are now >150bhp for example, and are large and heavy). Driven for economy, there high efficiency means they can return excellent economy, hence the >60mpg you see for the official drive cycle tests. But driven poorly, by the average motorist, those figures rapidly become "unattainable"!
By way of illustration, take two cars, one that does 25mpg, and one that does 50mpg. Both drive for 100miles.
Car A will have used 4 gallons (4=100/25)
Car B will have used 2 gallons (2=100/50)
Lets say both cars are poorly driven, and the drivers drive in such a fashion to use and extra gallon of fuel(an extreme example, used to illustrate the point).
As a result Car A consumption falls to 20mpg (=100/5) a drop of 5mpg
But Car B falls to 33mpg (=100/3) a drop of 17mpg.
This illustrates that is becomes proportionally more difficult to achieve the claimed fuel economy as that economy figure increases. Even though both drivers have "wasted" the same volume of fuel (1 gallon)
In extremis, a car that could travel from london to scotland on a single drop of fuel, could actually return zero mpg if you accidentally spilled that drop of fuel on the petrol station floor by mistake!!!
Modern cars are both highly efficient, but also high powered. As such, they can consume a large quanity of fuel very quickly if driven poorly. (most modern cars are now >150bhp for example, and are large and heavy). Driven for economy, there high efficiency means they can return excellent economy, hence the >60mpg you see for the official drive cycle tests. But driven poorly, by the average motorist, those figures rapidly become "unattainable"!
Agreed that in order to get these figures you need to drive 'appropriately' - I'd suggest that you need to drive a diesel differently to a petrol - five years of having a diesel daily it's incredible the different stats you get when driven prudently vs 'with verve'.
Still, if anyones got one and for example does the same commute as compared to a previous car I'd be intrigued what you're getting. I get the impression as cars get more complicated & MPG increases they also become harder to replicate in the real world - as noted on another thread my 54 plate Golf 2.0TDi is more efficient on my commute than my temporary company car 1.6 diesel Pug 308, despite supposedly having a 17mpg advantage!
Still, if anyones got one and for example does the same commute as compared to a previous car I'd be intrigued what you're getting. I get the impression as cars get more complicated & MPG increases they also become harder to replicate in the real world - as noted on another thread my 54 plate Golf 2.0TDi is more efficient on my commute than my temporary company car 1.6 diesel Pug 308, despite supposedly having a 17mpg advantage!
Excellent reply Max_Torque. Without understanding why, I believe the l/100km measure is more representative than MPG.
My commute to work is very easy on my car, 4 miles of local roads followed by 26 miles of dual carriage and motorway, and most of it against the flow of traffic.
Parkers.co.uk lists my old 1998 Audi A6 1.8T petrol as having an average of 32mpg, and I could regularly get 36ish from it if I behaved. My 2006 Skoda Octavia 2.0 TDI has an average of 51mpg and over the 60K miles I've driven I've got 52mpg (and I actually have the figures to calculate this).
My commute is pretty good for getting good fuel economy, but I've never struggled to achieve the average MPG with my current diesel car. The older petrol car did better than average but once off the easy commute it's real world average was noticeably less than it's official average (10 - 30% less).
Where I see the biggest difference is in my non-commuting driving. The petrol average dropped off very quickly to low 20s (big car, smallish engine) but the ability of the diesel (medium sized car, medium sized car) to maintain 42+mpg still impress me.
Long story short, diesel works very well for my particular commute, but if petrol catches up to the point where it can compete then I'm happy to have a look.
My commute to work is very easy on my car, 4 miles of local roads followed by 26 miles of dual carriage and motorway, and most of it against the flow of traffic.
Parkers.co.uk lists my old 1998 Audi A6 1.8T petrol as having an average of 32mpg, and I could regularly get 36ish from it if I behaved. My 2006 Skoda Octavia 2.0 TDI has an average of 51mpg and over the 60K miles I've driven I've got 52mpg (and I actually have the figures to calculate this).
My commute is pretty good for getting good fuel economy, but I've never struggled to achieve the average MPG with my current diesel car. The older petrol car did better than average but once off the easy commute it's real world average was noticeably less than it's official average (10 - 30% less).
Where I see the biggest difference is in my non-commuting driving. The petrol average dropped off very quickly to low 20s (big car, smallish engine) but the ability of the diesel (medium sized car, medium sized car) to maintain 42+mpg still impress me.
Long story short, diesel works very well for my particular commute, but if petrol catches up to the point where it can compete then I'm happy to have a look.
HemiCommander said:
My new car is fairly modern (2007) and has a cylinder deactivation system that runs only half the cylinders under light loads to save fuel. This enables it to achieve a truly remarkable combined fuel economy of 18mpg. Hooray for technology 
.
What the hell have you got?! .
Max_Torque said:
By way of illustration, take two cars, one that does 25mpg, and one that does 50mpg. Both drive for 100miles.
Car A will have used 4 gallons (4=100/25)
Car B will have used 2 gallons (2=100/50)
Lets say both cars are poorly driven, and the drivers drive in such a fashion to use and extra gallon of fuel(an extreme example, used to illustrate the point).
As a result Car A consumption falls to 20mpg (=100/5) a drop of 5mpg
But Car B falls to 33mpg (=100/3) a drop of 17mpg.
There is a problem with your explanation, and that is, that it is underlied by an assumption.Car A will have used 4 gallons (4=100/25)
Car B will have used 2 gallons (2=100/50)
Lets say both cars are poorly driven, and the drivers drive in such a fashion to use and extra gallon of fuel(an extreme example, used to illustrate the point).
As a result Car A consumption falls to 20mpg (=100/5) a drop of 5mpg
But Car B falls to 33mpg (=100/3) a drop of 17mpg.
The assumption is that a highly economical car driven in the same enthusiastic manner as a "wasteful" one will result in an identical "extra" amount of fuel used by both.
Otherwise, if you mean exactly what you write, then the comparison is not valid because the driving styles must inevitably have been different.
The truth must lie closer to the fact that the official MPG tests do not reflect everyday driving (whatever that may be) but are only of comparative value, and many car adverts do actually point this out.
Even with big bruisers, officially claimed MPG of (say) 18 is often reported to be in the single figures in the real world.
996TT02 said:
The assumption is that a highly economical car driven in the same enthusiastic manner as a "wasteful" one will result in an identical "extra" amount of fuel used by both.
And it's a valid assumption, because generally speaking, the "eco" cars still have a high power output, and so can still consume a lot of fuel making that power. The only difference is when you stop driving hard, and go back to pootling around, the low drag, narrow tyres, tall gears, stop-start, smart alternator, elecy PAS, multispeed transmission, all generate a lower load, and hence the car uses less fuel.Back in the day, when a fiesta had 40bhp, even though it was highly in-efficient, it would do 40mpg all day long however it was driven (because 40bhp doesn't take much fuel). Now a fiesta has 130bhp, although the light load efficiency is WAY better, it WILL use more fuel if you rag it because it makes 130bhp!
Max_Torque said:
996TT02 said:
The assumption is that a highly economical car driven in the same enthusiastic manner as a "wasteful" one will result in an identical "extra" amount of fuel used by both.
And it's a valid assumption, because generally speaking, the "eco" cars still have a high power output, and so can still consume a lot of fuel making that power. The only difference is when you stop driving hard, and go back to pootling around, the low drag, narrow tyres, tall gears, stop-start, smart alternator, elecy PAS, multispeed transmission, all generate a lower load, and hence the car uses less fuel.Back in the day, when a fiesta had 40bhp, even though it was highly in-efficient, it would do 40mpg all day long however it was driven (because 40bhp doesn't take much fuel). Now a fiesta has 130bhp, although the light load efficiency is WAY better, it WILL use more fuel if you rag it because it makes 130bhp!
Max_Torque said:
And it's a valid assumption, because generally speaking, the "eco" cars still have a high power output, and so can still consume a lot of fuel making that power. The only difference is when you stop driving hard, and go back to pootling around, the low drag, narrow tyres, tall gears, stop-start, smart alternator, elecy PAS, multispeed transmission, all generate a lower load, and hence the car uses less fuel.
Back in the day, when a fiesta had 40bhp, even though it was highly in-efficient, it would do 40mpg all day long however it was driven (because 40bhp doesn't take much fuel). Now a fiesta has 130bhp, although the light load efficiency is WAY better, it WILL use more fuel if you rag it because it makes 130bhp!
Yes I see your point.Back in the day, when a fiesta had 40bhp, even though it was highly in-efficient, it would do 40mpg all day long however it was driven (because 40bhp doesn't take much fuel). Now a fiesta has 130bhp, although the light load efficiency is WAY better, it WILL use more fuel if you rag it because it makes 130bhp!
Still thinking in old money, when an econobox only managed to push out 40bhp on a good day, 20C at sea level...
acme said:
Reading a few threads this year a number of people noted that they've got nowhere near the claimed figures on diesels
I can get near the figures claimed for my BMW 3.0 D - the problem is you need to keep speed down to something like 50/60, only be stationary when stop/start stops engine and not need to crawl in traffic, don't use too much throttle and warm start. Drive it normally and you are at least 20% down.The problem is the manufacturers are designing to the economy test rules not to achieve best overall economy and until EU sort out test it will stay that way.
I work for VW and recently had been driving the golf mk7 2.0 gt, was getting the announced mpg, bought the gf a MK 7 gold. 1.4 tsi manual and she is also getting the announced mpg. Yesterday I moved into the polo blue gt 1.4 tsi and only achieved 41 mpg far from anticipated mpg. Shall try again today on way to work see If I can get better economy
22Rgt said:
Im assuming this is what Audi call C.O.D, cylinder on demand? Just bought a new A1 1.4 TFSI with this engine, it produces 140PS and supposedly very low fuel usage figures, will have to wait and see whats reality..
Be intrigued to see what you get and or can get if you try. Gassing Station | General Gassing | Top of Page | What's New | My Stuff