alianmac

As a long standing member of the Institue of Advanced Motorists (IAM) who has been pondering whether Stop-Start is a good thing or not since I bought my 75PS GreenTech, I thought that I would ask for their advice on this matter. Below is my query - posted on 16 April - followed by the response that I received this afternoon. Seems pretty conclusive to me. I can't think of any reason for the IAM or the AAA to big up such systems if they are not what they claim to be. ================================================================ Hi, This email is a follow up to a response I made to a recent IAM questionnaire. In it, I said that I would appreciate advice on how to make best use of some of the more advanced technology in modern cars. It relates to the purpose of the stop start system that is fitted to many cars under branding such as "BlueMotion", "GreenTech", "Efficient Dynamics", etc. These are the systems that automatically shut down the engine of the car when it is stationary and the driver removes their foot from the clutch pedal. They then restart the engine when the clutch pedal is depressed again. There seems to be an assumption by the manufacturers that this happening automatically is "a good thing" and the driver should just go along with it. However, I am not so sure. I have been looking for a more in-depth analysis of these systems, what they actually achieve and what the best use of the actually is. I have not been able to find anything other than opinions expressed in discussion groups. I wondered if you had access to any analysis or research that shows what the benefits are? Reduced fuel consumption, improvements in air quality, allowing vehicles to qualify for lower tax bands/pass stringent emissions tests are the ones that come to my mind. Also I wondered if the IAM or any other independent and responsible driving organisation had done any real world testing to see how these systems work in real life and to develop guidelines for how to use them when driving in everyday traffic. For example, when in a traffic queue that is exhibiting stop start progress, should one stop and wait, rather than crawl gradually forward? Such behaviour runs the risk of irritating drivers behind. Likewise, an observant driver can see from other traffic lights and how long the lights affecting them have been from red that they might have a very short wait (or conversely a very long wait) before they will be allowed to progress. So what is the period that the engine has to be switched off before any cost (amount of fuel or air quality) has been exceeded? Thank you in advance for any assistance that you might be able to give me. =========================================================== Thank you for your query. These automatic stop-start systems are becoming almost universal for cars with piston engines, because it is relatively straightforward for manufacturers to do and it has significant advantages for both fuel economy (and thereby lower CO2 emissions) and for urban air quality. You raise some interesting questions which I’ll answer more or less in order, but first, I’m only going to deal with stop-start systems and that’s the name I’ll use. Branding such as “Blue Motion” or “Efficient dynamics” usually includes some other efficiency measures as well. The manufacturers claim fuel saving of around 5% for typical drivers and typical journeys. The IAM does not carry out testing of this sort, but the AAA (Automobile Association of America) did conduct independent tests on three cars in 2014 and found they used 5% to 7% less fuel when the system was enabled, which corroborates the manufacturers’ claims. Urban air quality is probably an even bigger winner, because most traffic jams are in towns, where the air quality problem is worst. NOx and particulate matter (soot) from diesel engines are serious health hazards and turning the engine off when not needed means they fall to zero. Many people have asked how long the engine has to be turned off to actually save any fuel. This is because there was a belief that it takes some extra fuel to get the engine started again, recharge the battery and so on. While this is true for a cold engine started after the car has been left overnight, it is not the case for stop-start systems. When you switch off the ignition and leave a car, you turn off the computers controlling the engine. When you return and start the engine, it turns over at least twice before starting, because the computer needs to work out the crankshaft position before injecting fuel and firing a spark plug (on petrol engines). Only after two complete turns does it “know” which piston is on the firing stroke and operate that injector and spark plug. The engine may take a little more than two turns to start, because fuel is wasted as it condenses on the cold metal surfaces instead of exploding. Petrol engines inject a lot of surplus fuel while cranking because of this, (the equivalent of the old fashioned choke) while diesel engines have glow plugs to heat the walls of the combustion chambers, which take a lot of energy from the battery. The effort of the starter motor turning a cold engine with thick oil, also takes a considerable amount from the battery which then must be re-charged, using more fuel. So, starting an engine from cold uses quite a bit of extra fuel. Things are very different when re-starting a stop-start system. The engine is warm, so no fuel condenses and no extra fuel or glow plugs are needed; the oil is thin so the engine turns over easily, the ignition has not been turned off, so the computer still “knows” the engine position and the result is the engine starts more or less instantly. The general engineering view is that if the engine is turned off for just a few seconds, it shows a net fuel saving. You raise an interesting point about how to drive these cars. You will certainly save more fuel and pollution if you wait while the traffic moves ahead of you, catch up with it, then stop again. This may frustrate some drivers, but most realise that while the traffic is queueing they won’t gain anything by crawling along continuously. Of course, if you are approaching a junction with a side road it is good manners to clear this as quickly as you can in case someone following wishes to turn into it, but like most things in driving, it’s a matter of observation and judgement. I hope this clarifies things for you and that you can enjoy driving your stop-start car (or whatever the marketing department of that manufacturer chose to call the system) with a greater understanding of the benefits.

Does it come away easily? (Not got my car to hand to check but do suffer from lots of leaves & other plant related debris when parked up in usual space.)

Mine is a 70PS Elegance Greentech bought earlier in the year with 50 miles on the clock. I have done 4574 miles on that I have put in. The petrol is mainly Esso as we have a local garage that undercuts everybody apart from the supermarkets and we don't have a supermarket close enough to make the extra mileage to fill up worthwhile. I don't use the upmarket petrol. My consumption across that mileage is 51.17mpg. Average cost per mile is 9.78 pence. When I got the car I had the opportunity to do a couple of late night trips that were pretty much identical in route, traffic conditions, etc. and used up about a tank of fuel. They were mostly (85 - 90%) motorway and was able to use the cruise control to minimise effects due to variation in right foot control. I did one journey with the speed set at 70mph and the other set at 75mph. At 70mph I got 55.9mpg. At 75mph I got 48.6mpg. I have found this instructive because the motorways around us (mainly M4, M40, M25) are not particularly user friendly if you drive at 70mph (lots of bunching and tailgating by busy-busy people, in a hurry to cause the next banking crisis or similar). In normal use, I do quite a lot of trips on these motorways between local towns and am getting slightly under 50mpg. So my hypothesis is that your MPG is mostly affected by how fast you drive and will follow some kind of bell curve with the people who do a lot of town driving getting lower mpg due to frequent pulling away, the people who have journeys along A roads/dual carriageways in the 40-60mph range getting the best figures (maybe approaching or exceeding 60mpg) and those of us who go more than 70mph for fun or for reasons of self preservation dropping back sub-50mpg. I keep the figures about the fuel I use out of interest. To be quite honest, even at the lower levels of fuel consumption I am quite happy with what I am getting and I am not filling up the local air with nitrous oxides as I was with my previous car. And I do enjoy driving the Citigo a lot when there is a decent road without much traffic. It is a hoot!

I see that you are in Bristol. It may be worth your while getting your Dad to have a look at BackInAction - as they have a branch in Bristol. This is the most relevant page on their website for your Dad. 4 months ago I could barely move - including struggling to get in and out of any car (including my Citigo), being in constant pain and taking ages to put on clothes - especially pants, trousers, socks and shoes. I have a range of back problems - caused by playing sport and also bad posture/badly adjusted seating when working at a computer/laptop. I am married to a (now retired) physiotherapist and had more or less exhausted her ability to keep my back mobile and pain free. I was already aware of the BackInAction Mobiliser product and decided to give it a try - initially via their assessment and free trial, followed by renting a unit for 2 months. The improvement was dramatic at first and then gradual. I am now pain free unless I have to stand for long periods and I can dress normally. I currently have CG-Lock fitted to my Citigo and use Sitting Partner on long journeys in the Citigo and whenever I drive my wife's Honda Jazz. Should my back problems return, I will definitely rent a Mobiliser again and maybe buy one if the economics dictate that it is financially wiser to do so. The total cost of the whole process was less than £500. Probably significantly cheaper than chopping in one car for another. I am not associated with BackInAction in any way other than being a customer. I used the Marlow store - who were very helpful and did not "oversell" me any of their products. I have no experience of the Bristol Store but it will cost nothing to visit.

As someone new to the teutonic efficiency of VAG, I am coming to the conclusion that it is remarkably similar to the gallic dis-organisation of Renault/Matra.

oxnboxn, That is a credible hypothesis - and of course there is no "extra" charge as the PID is fitted as standard on the Elegance. However, it does force one to have to use the PID even on short journeys. I will have a play and see if I can master the PID sufficiently to see if the buttons affect the information displayed on the PID. Don't anyone hold their breath!

I could understand it if mine didn't have the buttons on the RH stalk. But it does - so why did they fit the more expensive stalk if the MFA (their abbreviation for Multifunction display!?) was not going to be enabled? All I can think of is a) they ran out of buttonless RH stalks on the day that mine was made VAG-Tech fitted it when they added the cruise control because it has to match the LH stalk Both seem unlikely although not impossible.

I can confirm that the parts fit. Here are some pictures. Don't ask me why the auto-focus failed on the shots with the back seats down. It took me longer to find the Torx T40 bit than it did to fit the kit. It took me even longer to upload the images to Flikr and sort out the permissions on the album.......

I went to my dealer on Wednesday (Hughes Skoda in Farnham Common, Bucks). I asked if they supplied the variable floor kit. The guy struggled to find a kit on his accessories system. So I gave him the part numbers from this forum - by actually bringing up the post on my smartphone and putting it on the desk in front of him. He copied the numbers into his parts system and gave me a price of £105.10, which I paid there and then by debit card. I got a call this morning - saying that they parts were in. I have just been and fetched them. My invoice says: F1S0 858 831 F8 2V N/STOCK MOUNTING 1x £ 8.06 F1S0 858 832 F8 2V N/STOCK MOUNTING 1x £ 8.06 F1S0 858 855 E1 BS N/STOCK PLATFORM 1x £ 67.80 FN 910 268 02 N/STOCK BOLT 6x £ 3.66 (£0.61 each) Net £ 87.58 Gross (inc VAT) £105.10 So, I reckon that you could go with that order and pay £112.54 to the VW dealer. Or you could see if your local Skoda dealer matches what I have paid (or is maybe slightly cheaper on account of the Thames Valley being an expensive place to do business). Or you could try a SEAT garage to see if they are cheaper still (as rumoured). If you really want to be sure, give me a few minutes to find a Torx 40 bit stick my head in the boot of the car. I will then confirm for certain that the parts fit.

An interesting question has emerged with regard to the multifunction display on my car. By multifunction display, I mean the ability to change what is displayed on the LCD panel mounted at the bottom of the speedo using buttons on the right hand stalk. It may or may not be due to the fact that I had Cruise Control fitted by the dealer rather than as a factory option. Do those of you with 75PS Elegance Greentech Citigo's have functioning multifunction displays? I have the toggle button on the end of the right hand stalk (referred to as Button A in the user manual and labelled "Trip" on the stalk) and the "on/off" type button on the underneath of the stalk (referred to as Button B in the user manual and labelled "OK/Reset" on the stalk). So I seem to be equipped to use the memory, clock and driving information aspects of the multifunction display. However, when I press the buttons (with the ignition switched on I hasten to add), nothing happens with the display. All I can do is swap between trip and odometer, time and temperature using the push buttons built into the screen of the speedo. I have raised this with the dealer - and they are pondering whether it is an issue or not. Their challenge is that they do not have an unmodified 75PS Elegance Greentech Citigo to compare it with and none of their documentation is categoric as to whether the multifunction display is a feature of a standard car of that spec or whether I have acquired the buttons on the stalk as a result of VAG-Tech fitting the cruise control. If anyone does have a functioning multifunction display, I would be very interested to hear the trim level of your Citigo and the year. Thanks in advance. Regards, Malcolm

The second tank returned 55.9mpg. The journeys under cruise control were very similar - almost identical route, same time of day, similar weather, similar traffic conditions. The second tank had about 10 miles more motorway driving and courtesy of the move to intelligent motorways between Junctions 27 and 30 of the M1 about 30/340 miles of the first tank and 40/350 miles of the second tank was spent at 50mph. The remainder of the time was spent at the cruise control speed for the journey. So I think that this is a reasonable comparison that slightly overstates the fuel consumption benefit of driving at 70mph. Regards, Malcolm

I bought a 64 plate pre registered Citigo 75ps manual Elegance 5 door with 36 miles on the clock in April. It was not factory fitted with cruise control. I asked the salesman about having cruise control fitted. His reply is below: The answer is yes, it can be fitted to a used car. The only issue is price. We use a company called Vag-Tec who only do retro fitting to VW, Skoda and Audi. They use genuine parts and are less expensive than our own workshop but even cost price from them is £349 plus VAT. I had it fitted as part of the purchase price that I agreed with the dealer. I suspect that it would have cost £450-ish had I gone to VAG-Tec direct as an aftermarket job. I can confirm that it works - as I have now used it for two x 340 mile round trips. The first time I set it at 75mph and the car pulled quite happily up and down the hills along the various motorways. Including about 55 miles of stop-start city driving, that tank/journey achieved 48.6 mpg. The second time I set it at 70mph. I will be filling up the tank after the second trip in the next couple of days to see how much difference 5 mph makes. .