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-   -   Why you must practice the "Idling Rule" with Turbo-Charged Cars (https://www.team-bhp.com/forum/technical-stuff/131875-why-you-must-practice-idling-rule-turbo-charged-cars-16.html)

During my maruti 800 days, there were multiple times I had run fully dry and had to get a lift to the nearest petrol bunk to get some petrol. A 1 or 2 litre bottle was a constant accessory in the car during those days. One of my friend who had a Maruti1000 also went through the similar process occasionally... College days :D Never faced any mechanical issues with either of the cars due to this.

When I moved on to Honda city (first dolphin model), there was the indicator light inside the speedo to indicate the car was running on the last 5-7 litres of petrol. On checking with the ASC, they told me never ever to run till the last drop. As it could damage the catalytic converter and replacement of which could be costly. Am not a technical person and hence cant comment on this. However, I followed it religiously never to run dry. After almost 7-8 yrs driving the City, its become a sort of habit with all the cars. The only time I faced this issue recently was when I used the pick and drop facility for XUV servicing. The car usually came back with the fuel so low that the "distance to empty" on the IS screen would be showing 0. I would be really tensed till I got to the nearest pump. So I have stopped using the pick and drop facility, for various reasons including this.

FundaG

It as happened to be a couple of times , stalled the car out of carelessness but i just crank it again , have to be realistic , i cannot wait 30 seconds and hold up traffic for my benefit. And quite frankly you being from Delhi would know that the chances of someone deciding to come out of their car and give you a piece of their mind is high enough anyway :)

But whereever else i can i follow a 45-1 minute rule , whether its getting to or coming back from office , stopping to shop someplace , highway driving , irrespective.

If one is not supposed to turn off a engine, then what about the Micro Hybrid sys in XUV which does that on a traffic light stop?

Believe this point was discussed earlier too. I dont think a once in a while stalling of the car is going to affect the turbo. This is meant to happen to every car at some point of time depending on some situation. Todays turbos can surely withstand such one-off incidents. And again as the car was running, one does not need to wait for 30 sec to start it again.

Coming to the microhybrid system in XUV, there are owners who use it regularly and others like me who have switched it off. As such using the microhybrid during city driving may not pose any problems for the turbo considering the traffic and the speeds would be 30-50kmph at the max. Hence turbos will not get heated up to that extent that it would need too much time to cool down. If really required one can keep the clutch depressed for a few additional secs before the microhybrid gets activated . But end of the day the decision to use the feature or not is totally owners take.

FundaG

I normally switch off auto start/stop function unless I plan to go in to city centre. Most of the signals on my daily route don't hold me for more than 20 seconds, and I think auto start/stop in such situations would unnecessarily strain the battery without significant benefits.

Joju

Off-Topic..
IIRC this would lead of burning the Friction Plate (I read it somewhere on this forum) if the Clutch pedal is kept pressed as the Torque of Diesel would put pressure on the Driven Wheels.
The matter in that thread was somewhat like this "Lift one or both of the driven wheel(s) or and engage 1st gear and keep the Clutch pedal pressed. You will notice that the Wheel(s) will start rotating. Now you can imagine how much the Clutch-related part has to bear when you keep the pedal pressed".

I have experienced/felt this that after about 15-20 seconds, after coming to a full stop (& switching off all electrical components except the engine) the car tends to get quieter & kind of settles down. You will notice this at a quiet place, even with windows up. Maybe the turbo stops spinning then. This si when I cut the ignition.

If at a busy/crowded place, I simply follow the 30 second rule.

Why do you switch it on/off at all? Why not leave it on all the time? Every 20 seconds of engine down time, is fuel and emission saved. that's what it was designed for. I wouldn't worry to much about the battery at all. These cars were designed as start/stop so battery and turbo should cope with the inherrent conditions that brings. If the driver needs to think about turbo idling and battery condition it sort of defeats the purpose doesn't it. what does the owner manual say about this?

In fact, I don't know, but I would imagine the car's electronics do monitor the battery and would/should disable the start/stop system if the battery condition isn't adequate? Not sure, does anybody know?

Sounds odd to say the least. As long as you keep the clutch pedal fully depressed, the clutch plates don't incur any real friction/wear. The only part that does incur some wear is the throw bearing. But that should not be a problem at all. Its designed to accomodate a full clutch pedal down repeadetly for extensive periods of time.

What you describe might occosianaly happen, but its' more due to what I would call 'residual" friction. You put your hand on the wheel that wheel that rotates and it'll stop. There is no torque in it at all, hence no wear on the clutch plate. If the car is idling and you press the clutch, put it in 1st and keep it like that for a very long time, your throw bearing will wear out long before the clutch does. How many posts have we seen on this forum about throw bearings wearing down? Exactly, doesnt happen often, part of normal operation of a car, nothing special.

In order for the engine to "stop" automatically two conditions need to be met (on a manual). One, the clutch pedal needs to be in resting position (ie not depressed) and two, the gear selector must be in neutral.

Jeroen

Jeroen, 20 seconds is kind of upper bound in my daily home-office drive. Often, it is less than 10 seconds, especially when I wait to get onto a priority road. I am sure the saving in such occasions will be minuscule, if any. I personally prefer to avoid stop/start, when the saving is infinitesimal. However, I do keep auto start/stop on when I go to crowded city centres.

The manual says auto start/stop will be operational only when the battery is sufficiently charged. But that does not mean it will not affect battery life, right? I have not seen any mention of turbo in the manual in relation to auto start/stop.

Joju

Thanks, as I thought/suggested the car (Electronics) monitors the state of the battery and will prevent the start/stop function from kicking in, if the battery health state is insufficient.

Battery life is amongst others, depended on the number of discharges/charges, so called cycles. In this case, the car and thus its battery was specifically developed to cope with a relatively high number of 'starts'. Also, bear in mind, once an engine has been running and has reached its normal operating conditions it takes a lot less power to restart the engine again. It's not as if a restart discharges the battery completely or in fact anywhere near full discharge.

I would imagine that all other factors influencing battery life, are of a much greater impact then the number of starts. So I don't think there is a need to switch off the start/stop function with respect to battery life.

Here's in interesting article on batteries and what determines battery life:

http://www.mpoweruk.com/life.htm#dod

Jeroen

Agree with you that there are other factors that influence battery life more than that start/stop function does. However, for my kind of use (I checked it today on my way back from office - on average, the start/stop system saves 9 seconds of idling per start/stop) it does not really save much. Effect on starter motor, unpleasant vibration while starting up, un-known effect on turbo, and other potential issues in long term are reasons to keep it switched off.

Yes, the manufacturers must have considered all the factors before introducing this feature. But they have a very strong reason to have auto start/stop - to meet emission norms.

Joju

Are you saying they are not meeting the emission norms without the start/stop system? I don't think so, certainly in Europe this is not the case.

The start/stop system enhances fuel efficiency and reduces emissions, but these engines are perfectly capable of meeting modern emissions norms on their own.

to put it bluntly, I still think these start/stop systems are more of a marketing ploy then anything else. Although, admittedly they do reduce fuel consumption and emission.

Jeroen

No, I was not saying they don't meet emission standards without start/stop system (well, it is probable that some models make a photo-finish when Euro 6 becomes the norm).
But there is huge pressure on manufacturers to reduce the emission as much as possible. It is expected that some of the German manufacturers won't be able to meet European emission standards in originally planned time frame, and hence the govt blocked EU move to enforce the original plan.
The manufacturers cannot get the government to bat for them, unless they show that they are doing their best. And yes, as you mentioned, auto start/stop helps in marketing.

http://www.spiegel.de/international/...-a-908176.html

Joju

Frequent limp mode with MIL light on captiva. OBD codes P0047 and P0045. Any suggestions?

There was a Fifth Gear episode where Tiff Needel tested a european car with auto start/stop system engaged in city driving and found that it was approx 10-15% more efficient than with the system switched off. If it is a deliberate decision on the part of the manufacturer to introduce this technology, one would expect them to do the homework in terms of starter motor wear, battery wear and turbo wear.

Here is the youtube link to the episode Fifth Gear episode