ACT - How does it work?

[Leeboy]

Now that my 1.4 ACT Superb has a few miles under its belt, it is now happier than ever to run in two cylinder mode. Today it returned 64.5 mpg on a 75 mile run from Amesbury to Leatherhead, running on two cylinders from several minutes at a time.

This led me to ponder whether if this has any detrimental effect. The oil temp under mixed driving normally sits around 100°C whereas as at 65 to 70 mph today it was sitting at 91°C which would be expected because the engine is generating half as much heat from two cylinders, so is this a problem for oil life or engine wear? And presumably the cat is operating below optimium temperatureand would this cause a problem?

Moreover though, does the engine switch which cylinders it deactivates? One and three, then next time two and four or whatever the firing order may be. Presumably it should do this to even up carbonisation of the cylinder and valves, and even out wear on the bores. Or does none of the above matter?

I think this tech should be on all new petrol engines, do any other manufacturers outside of VAG make use of such systems? It certainly makes a difference, my partner's mk6 Golf 1.4 tsi doesn't have ACT and I can only get 45 mpg out of it whereas Superb will do at least 5mpg better on the same cross country route when driven in a similar manner.

[dstev2000]

Here you go:

 

 

ACT basically stops fuel injection and closes all 8 valves across cylinders 2 and 3. 

[SuperbTWM]

I wouldn't worry about the cat, even with 2 cylinders its probably working more efficiently than it ever would on a diesel

[Rainmaker]

I've nothing to add on the ACT front, but I had to say:

 

Jeez, 65mpg out of a large petrol car weighing one and a half tonnes that still manages to do 0-60 in 8 seconds. That's some going, and must really sweeten the deal for a family runabout. My brother's money saving wasting 'blue ultra eco' diesel shopping trolley doesn't return that... downhill... with the wind behind it. You must be delighted!

 

Now go and post in the diesel real world (struggling) MPG thread saying "65MPG out of mine today!"... then edit it ten minutes later to say 'Oops, I meant from a petrol. Sorry, wrong thread...". Light fuse, stand well back.    *

 

 

 

 

 

 

* Sorry, I'm an ass with the sense of humour of a delinquent child when I want to be. I'll remove my tongue from my cheek now... Maybe.

[drewpost]

That's impressive! I'll have to keep an eye out for you as I haven't seen any other Superb IIIs in Leatherhead except mine!

Sent from my iPhone using Tapatalk

[dstev2000]

Hopefully this technology will move up to the 2 litre units in due course. The Bentley/Audi V8 has had it for a while now, and the Audi A8 W12 is using it too, under the 'COD' (Cylinder On Demand) moniker. If the 220 or 280 had ACT, it would've been a strong contender over the 190 diesel I eventually chose. My mileage of 25-30,000 per annum meant the 280's fuel consumption was out of the question for the time being. 

[Leeboy]

Here you go:

ACT basically stops fuel injection and closes all 8 valves across cylinders 2 and 3.

Thanks for finding that, looks complicated tech but simple in concept. So it's always 1 and 4 that run. Wonder if it will impact on engine wear 100,000 miles later although I've got the car on 3.5 years max PCP with a 20,000 miles pa limit, so hopefully won't find out!

[Leeboy]

I've nothing to add on the ACT front, but I had to say:

Jeez, 65mpg out of a large petrol car weighing one and a half tonnes that still manages to do 0-60 in 8 seconds. That's some going, and must really sweeten the deal for a family runabout. My brother's money saving wasting 'blue ultra eco' diesel shopping trolley doesn't return that... downhill... with the wind behind it. You must be delighted!

Now go and post in the diesel real world (struggling) MPG thread saying "65MPG out of mine today!"... then edit it ten minutes later to say 'Oops, I meant from a petrol. Sorry, wrong thread...". Light fuse, stand well back. *

* Sorry, I'm an ass with the sense of humour of a delinquent child when I want to be. I'll remove my tongue from my cheek now... Maybe.

Lol! It is indeed rather good for a car of this size. Clearly it won't get near that figure if I do drive it like the 0-60 time allows, but this was a steady run with only one bit of stop start for three or four minutes at the end of the journey, but that's fine.

If it will do 60+ mpg routinely on journeys up and down the country I'll be more than happy. My employer pays me 45p a mile to compensate for using my own vehicle for business. So by my reckoning per mile it's less than 10p on fuel leaving 35+ pence to cover the PCP monthly payment, service and insurance. So by my reckoning if petrol stays around the current pound a litre level leaves me quids in doing around 1500 business miles a month!

[bigjohn]

Thanks for finding that, looks complicated tech but simple in concept. So it's always 1 and 4 that run. Wonder if it will impact on engine wear 100,000 miles later although I've got the car on 3.5 years max PCP with a 20,000 miles pa limit, so hopefully won't find out!

 

My main worry here is the width of the cam lobes - they look quite thin - we'll have to see about longevity

 

However one thing seems to be a theme - Later euro 6 diesels seem to be getting less economical but the euro 6 petrols seem to be getting more economical, in real life conditions

Edited 25 February, 2016 by bigjohn

[Alfaspider]

I do a daily comute of 65km and back home in my Seat leon 150act. I have a long term average of 6l/100km. Highway and 5km of city driving in each direction, 120km/h set on cc. So far avoiding 2l tdi has paid off brilliantly. Not to mention whisper like engine, no shaking etc.

[SuperbTWM]

 

 

However one thing seems to be a theme - Later euro 6 diesels seem to be getting less economical but the euro 6 petrols seem to be getting more economical

 

Yes but their track record of reliability on petrol engines hasn't been great, the 1.2 and 1.4 TSI engines were plagued with problems with engine replacements needed not to mention the oil consumption issues on the 2.0 as well. I know they have supposed to have sorted these issues out on the newer engines but there are still plenty of pros and cons to petrol or diesel.

 

If the emissions regulations weren't so tight and fuel so expensive we could drive much simpler and more reliable cars

[Prykey]

Yes but their track record of reliability on petrol engines hasn't been great, the 1.2 and 1.4 TSI engines were plagued with problems with engine replacements needed not to mention the oil consumption issues on the 2.0 as well. I know they have supposed to have sorted these issues out on the newer engines but there are still plenty of pros and cons to petrol or diesel.

 

If the emissions regulations weren't so tight and fuel so expensive we could drive much simpler and more reliable cars

Yes, a small block V8 with a Holley 4-Barrel Carb would fit the bill nicely

[RickTT]

Yes but their track record of reliability on petrol engines hasn't been great, the 1.2 and 1.4 TSI engines were plagued with problems with engine replacements needed not to mention the oil consumption issues on the 2.0 as well. I know they have supposed to have sorted these issues out on the newer engines but there are still plenty of pros and cons to petrol or diesel.

 

If the emissions regulations weren't so tight and fuel so expensive we could drive much simpler and more reliable cars

 

|You mean like America does..

[bigjohn]

Yes but their track record of reliability on petrol engines hasn't been great, the 1.2 and 1.4 TSI engines were plagued with problems with engine replacements needed not to mention the oil consumption issues on the 2.0 as well. I know they have supposed to have sorted these issues out on the newer engines but there are still plenty of pros and cons to petrol or diesel.

 

If the emissions regulations weren't so tight and fuel so expensive we could drive much simpler and more reliable cars

 

The thing that scares me about new euro 6 diesels now if you keep a car long term are the DPF & SCR systems. If/when these fail they are big ticket items Recent EGR's a pain as well. Not usually a problem if you get rid after 2-3 years

 

The last low tech really reliable Skoda engine was the special edition 2011 1.6 MPI Octavia II SE  fitted with the 1.6 8v engine of old and 5 speed box. No direct injection etc............. However was somewhat high revving on the motorway but real life economy reasonable

Edited 23 February, 2016 by bigjohn

[Prykey]

The thing that scares me about new euro 6 diesels now if you keep a car long term are the DPF & SCR systems. If/when these fail they are big ticket items Recent EGR's a pain as well. Not usually a problem if you get rid after 2-3 years

 

The last low tech really reliable Skoda engine was the special edition 2011 1.6 MPI Octavia II SE  fitted with the 1.6 8v engine of old and 5 speed box. No direct injection etc............. However was somewhat high revving on the motorway but real life economy reasonable

I thought that the 1.9 130 TDI was pretty bomb proof, I didn't go diesel as I only do low mileages i.e. under 10k miles in 29-months and don't want the hassle of EGR, DPF or SCR issues so the 280PS TSI seemed to be perfect!

Edited 23 February, 2016 by Prykey

[woody3537]

The thing that scares me about new euro 6 diesels now if you keep a car long term are the DPF & SCR systems. If/when these fail they are big ticket items Recent EGR's a pain as well. Not usually a problem if you get rid after 2-3 years

 

The last low tech really reliable Skoda engine was the special edition 2011 1.6 MPI Octavia II SE  fitted with the 1.6 8v engine of old and 5 speed box. No direct injection etc............. However was somewhat high revving on the motorway but real life economy reasonable

The exact reason I have gone for petrol after 15 years of diesels and do not regret it. I'm not getting great fuel economy yet but I'm only 600 miles in and I'm already getting the same as my laguna diesel. Hoping it's going to get better too.

[dstev2000]

Thanks for finding that, looks complicated tech but simple in concept. So it's always 1 and 4 that run. Wonder if it will impact on engine wear 100,000 miles later although I've got the car on 3.5 years max PCP with a 20,000 miles pa limit, so hopefully won't find out!

I suspect VW have tested this beyond the realms of realistic mileage. That being said, there's no substitute for real world conditions that can never be fully replicated in the lab or on the test track. As with most new technology out there, only time will tell......

[SuperbTWM]

I thought that the 1.9 130 TDI was pretty bomb proof, I didn't go diesel as I only do low mileages i.e. under 10k miles in 29-months and don't want the hassle of EGR, DPF or SCR issues so the 280PS TSI seemed to be perfect!

The whole PD range was pretty reliable, I has a PD100, 105 and 130 in the last 6 years and the only major problems I has was DMF issues.

 

I only do about 10K but I still think having a diesel is cheaper, especially if you do your own repairs, and not forgetting the tax is ridiculously cheap. Their are alternatives to replacing the DPF and EGR......just delete them as they fail

 

That said, I wouldn't mind a 280PS TSI one day, the last Petrol I had was a 225 TT and running that on Vpower and only getting 350 miles to a tank practically doubled my fuel spend from my previous Golf. It was a fun car though

Edited 24 February, 2016 by SuperbTWM

[bigjohn]

The whole PD range was pretty reliable, I has a PD100, 105 and 130 in the last 6 years and the only major problems I has was DMF issues.

 

 

Agreed re 1.9 but they are all getting old now

 

The 2.0 pd wasn't as good though

 

Oh and never buy a pd fitted with a DPF

Edited 24 February, 2016 by bigjohn

[Rainmaker]

I only do about 10K but I still think having a diesel is cheaper, especially if you do your own repairs, and not forgetting the tax is ridiculously cheap. Their are alternatives to replacing the DPF and EGR......just delete them as they fail

 

Not wishing to start any unintentional flame wars, but I really don't agree with that mate. The DPF especially cuts down drastically on the huge amounts of dangerous pollution spewed out by diesel engines, which has a real and serious impact on the health of those subjected to it. Given that most diesels have been shown to produce between 20 and 40 times more particulates and NOx in the 'real world' than is allowed already, you can only imagine how bad it'd be with a DPF and EGR 'delete'.... Pretty selfish imho, not to mention illegal. No car will pass an MOT with a 'deleted' DPF any more, and quite rightly so.

 

Don't get me wrong I hate the way modern emissions regs have strangulated the basic and reliable diesel engine, but the vast amounts of respiratory and cardio diseases caused by NOx and particulates really doesn't justify removing what is essentially safety tech, just to save a few quid. That's coming from someone with a username like mine, who drove diesels over half a million miles in the last decade. So, certainly not an off the cuff blind hate post. Just my opinion based on the available evidence.

[SuperbTWM]

Not wishing to start any unintentional flame wars, but I really don't agree with that mate. The DPF especially cuts down drastically on the huge amounts of dangerous pollution spewed out by diesel engines, which has a real and serious impact on the health of those subjected to it. Given that most diesels have been shown to produce between 20 and 40 times more particulates and NOx in the 'real world' than is allowed already, you can only imagine how bad it'd be with a DPF and EGR 'delete'.... Pretty selfish imho, not to mention illegal. No car will pass an MOT with a 'deleted' DPF any more, and quite rightly so.

 

Don't get me wrong I hate the way modern emissions regs have strangulated the basic and reliable diesel engine, but the vast amounts of respiratory and cardio diseases caused by NOx and particulates really doesn't justify removing what is essentially safety tech, just to save a few quid. That's coming from someone with a username like mine, who drove diesels over half a million miles in the last decade. So, certainly not an off the cuff blind hate post. Just my opinion based on the available evidence.

I understand where you are coming from and I totally agree with the points you have made.

 

If I was deleting the dpf for power reasons or economy I would see it as a bit selfish, but if its saving me a grand by not replacing a faulty one I will happily be a selfish NOx murderer. You could say driving about in a big engined 4x4 for no reason is selfish as well but plenty of people have range rovers, X5's and Q7's when they could manage with a Golf bluemotion.

[Breezy_Pete]

DPFs don't do anything to reduce NOx, EGR does though.

[Rainmaker]

I understand where you are coming from and I totally agree with the points you have made.

 

If I was deleting the dpf for power reasons or economy I would see it as a bit selfish, but if its saving me a grand by not replacing a faulty one I will happily be a selfish NOx murderer. You could say driving about in a big engined 4x4 for no reason is selfish as well but plenty of people have range rovers, X5's and Q7's when they could manage with a Golf bluemotion.

 

That's true, but provided the RRs and X5s have working emissions equipment they'll still be far cleaner than a smaller car with said equipment illegally removed. Far cleaner again to burn petrol (ironically). If replacing the DPF will cost a grand (it shouldn't for most cars these days) then perhaps that should be factored in the total cost of ownership sums before buying, at which point the sums start pointing back to a different engine... I don't want to derail this thread any further, just wanted to add my .02 (which we've both had chance to do). Not really worth starting a new thread over, so let's leave it there. :beer:

 

DPFs don't do anything to reduce NOx, EGR does though.

 

I didn't say they did mate, unless you was replying to something SuperbTWM said? Either way I'm conscious of derailing the OP's ACT thread as I said so I'll shut up now.

[Breezy_Pete]

That's true, but provided the RRs and X5s have working emissions equipment they'll still be far cleaner than a smaller car with said equipment illegally removed. Far cleaner again to burn petrol (ironically). If replacing the DPF will cost a grand (it shouldn't for most cars these days) then perhaps that should be factored in the total cost of ownership sums before buying, at which point the sums start pointing back to a different engine... I don't want to derail this thread any further, just wanted to add my .02 (which we've both had chance to do). Not really worth starting a new thread over, so let's leave it there. :beer:

 

 

I didn't say they did mate, unless you was replying to something SuperbTWM said? Either way I'm conscious of derailing the OP's ACT thread as I said so I'll shut up now.

I was.