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Old 16th December 2019, 21:42   #421
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Default Re: Why you must practice the "Idling Rule" with Turbo-Charged Cars

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Originally Posted by Jeroen View Post
You should read the owner manual and follow to the letter.

Jeroen
I cross checked with the Mini Driver’s guide which I ve downloaded to my iPhone/ iPad. It very clearly states; “Dont warm up the engine with the car at a standstill; instead set off immediately, driving at moderate engine speeds. Do not use the accelerator when starting the engine.”
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Old 16th December 2019, 23:16   #422
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Default Re: Why you must practice the "Idling Rule" with Turbo-Charged Cars

^^^^ There you go! If everybody would just read their car owner manual we could close down this thread altogether!

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Old 17th December 2019, 06:46   #423
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Default Re: Why you must practice the "Idling Rule" with Turbo-Charged Cars

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^^^^ There you go! If everybody would just read their car owner manual we could close down this thread altogether!

Jeroen
However, it says nothing about coming to a halt and the “best practices” around that. Considering that the Turbo Petrol engine spools up pretty quick and in case one has been driving quickly or overtaking a bit here and there, shouldn’t one allow the engine to idle a bit before shutting down completely when coming to a halt?
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Old 17th December 2019, 12:00   #424
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Default Re: Why you must practice the "Idling Rule" with Turbo-Charged Cars

IMHO, it doesn’t hurt to idle the engine for 10 seconds on a cold start and idle the engine for 30 seconds after a spirited drive.

Theory does educate me. But I am comfortable following the above rule, as it gives me peace of mind.

Maybe I am from old school. 😊
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Old 17th December 2019, 12:13   #425
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Default Re: Why you must practice the "Idling Rule" with Turbo-Charged Cars

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Originally Posted by shankar.balan View Post
However, it says nothing about coming to a halt and the “best practices” around that. Considering that the Turbo Petrol engine spools up pretty quick and in case one has been driving quickly or overtaking a bit here and there, shouldn’t one allow the engine to idle a bit before shutting down completely when coming to a halt?
Always idle for a minimum of 30 seconds IF driven spiritedly and slightly less idling time if the car was driven sedately without spooling the turbo much.
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Old 17th December 2019, 12:18   #426
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Default Re: Why you must practice the "Idling Rule" with Turbo-Charged Cars

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Originally Posted by shankar.balan View Post
However, it says nothing about coming to a halt and the “best practices” around that. Considering that the Turbo Petrol engine spools up pretty quick and in case one has been driving quickly or overtaking a bit here and there, shouldn’t one allow the engine to idle a bit before shutting down completely when coming to a halt?
If it is not mentioned in your manual, there is no need. Trust me, anything worth mentioning will be put in the manual by your car’s manufacturer!

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Originally Posted by Chethan B G View Post
IMHO, it doesn’t hurt to idle the engine for 10 seconds on a cold start and idle the engine for 30 seconds after a spirited drive.

Theory does educate me. But I am comfortable following the above rule, as it gives me peace of mind.
Peace of mind is important, so please by all means, go ahead of course.

Engine wear due to cold starts is a very, very slow cumulative process anyway. 10 seconds is not much, but it is ten times as much as 1 second.

Is engine wear due to cold starts a real issue. Probably not. Very few people read car owners manual. We have a thread on this very topic and even the members of a car forum seem not to bother, mostly.

Even so, how many posts can you find on this forum of members who had to overhaul piston, rings and cylinder bushes? It is pretty rare. And if it happens it is nearly always at considerable high mileage. But of course, other tell tales can be high lub oil consumption. Again, car forums the world all over are awash with myth how much is allowed. Again, I advise to check your can owner manual. You will find that on many engines 1l/1000 km is still ok. All engines at some point in time will start showing oil consumption, but the number of cold starts and how long you let it idle before setting off, is an important factor.

If you check out the various tips from experts on buying second hand cars: Be weary of cars that have run relatively low mileage per year. Those are cars that were likely used for lots of short drives. E.g. 25.000 km in five years. Go for that car that has done 100.000 km in three years. Engine wear on the latter is likely to be considerable less.

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Old 17th December 2019, 14:34   #427
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Default Re: Why you must practice the "Idling Rule" with Turbo-Charged Cars

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IMHO, it doesn’t hurt to idle the engine for 10 seconds on a cold start and idle the engine for 30 seconds after a spirited drive.
+1. If not to warm up the engine, at least to circulate the oil around a bit before loading the engine.
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Old 17th December 2019, 15:01   #428
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Default Re: Why you must practice the "Idling Rule" with Turbo-Charged Cars

Honda says to idle the engine at least for 10 seconds before turning off the engine. But has no words on waiting after turning on.
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Why you must practice the "Idling Rule" with Turbo-Charged Cars-5a54e833b0354099a2706f92c3adaf26.png  

Why you must practice the "Idling Rule" with Turbo-Charged Cars-50ce01ee32b34397a507b5411d499f9c.png  

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Old 17th December 2019, 15:19   #429
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Default Re: Why you must practice the "Idling Rule" with Turbo-Charged Cars

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Originally Posted by ds.raikkonen View Post
+1. If not to warm up the engine, at least to circulate the oil around a bit before loading the engine.
I would like to understand the technical explanation for this. Because with my limited technical knowledge I do not see the need at all.

Most car engines rely on two types of lubrication; forced lubrication and splash lubrication.

All lub oil pumps on car engines are positive displacement pumps. The moment you start cranking the engine, the oil pump starts pumping oil. All oil pipes and channels on the engine are pretty minute in diameter. Which effectively means oil gets everywhere almost immediately as you start cranking.

You can check for yourself; Take the valve cover of your engine. Crank the engine without starting and you will see the oil coming out everywhere!

So all forced lubrications items such as bearings, be that crankshaft bearings, or valve rocker arm bearings, all get lubrication almost immediately. Check the oil pressure light on your dashboard. When you crank the engine, as soon as the engine starts it will extinguish. Which means you have full lub oil pressure almost immediately. Normally almost all lub oil piping and channels retain their oil at shutdown. Oil is not compressible, so it means you have good oil pressure and flow everywhere almost immediately.

For the parts that get splash lubrication it is slightly different. That would be very often the piston rings / cilinder bushes and for instance parts inside the valve cover (other then afore mentioned bearings).

Because the oil is cold, relatively thick and the engine is running at idle, little splash lubrication takes place. Also, because the oil is thick, all metal is cold it will not stick and it will provide little lubrication. By letting it idle you are making this no splash lubrication situation last!

In fact, to my earlier point, that is part of the reason you get extra wear. In order for splash lubrication to become effective you need warm oil, and all metal bits at operating temperature. Low rpm’s don’t give much splash either and certainly not with cold thick oil.

So just start and drive away. Sitting there for 10 seconds idling, if it makes you feel comfortable, by all means. But in reality it is always better to set off immediately. It is also much better for the environment!

Only if an engine is brand new, has been overhauled, or is starting at extreme ambient temperature should you consider letting it idle for a few seconds.

There is a reason why manufacturers recommend you to drive away, slowly, straight away. Any thought on to why, technically speaking, you believe your procedure is better than the manufacturers?

Again, nothing is going to break immediately one way or the other. We are talking some additional wear for 10 seconds, but it does add up over the life of an engine.

But as I have said many many times, when in doubt consult the owner manual. Do what it says, and don’t worry about what it does not say

Jeroen

Last edited by Jeroen : 17th December 2019 at 15:22.
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Old 17th December 2019, 15:24   #430
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Default Re: Why you must practice the "Idling Rule" with Turbo-Charged Cars

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Originally Posted by shankar.balan View Post
I cross checked with the Mini Driver’s guide which I ve downloaded to my iPhone/ iPad. It very clearly states; “Dont warm up the engine with the car at a standstill; instead set off immediately, driving at moderate engine speeds. Do not use the accelerator when starting the engine.”
For the Skoda Superb, the manual also asks not to idle/warm up the engine, and set off immediately.
However, it also says one should idle the car for 1 minute to cool down the engine before switching it off.
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Old 17th December 2019, 18:45   #431
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Default Re: Why you must practice the "Idling Rule" with Turbo-Charged Cars

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Originally Posted by Jeroen View Post
I would like to understand the technical explanation for this. Because with my limited technical knowledge I do not see the need at all.

But as I have said many many times, when in doubt consult the owner manual. Do what it says, and don’t worry about what it does not say

Jeroen
Point noted. My understanding was that oil will take a 'few' seconds at the least to circulate in all the channels after starting the engine in the morning (or after a long duration).

Although I do wait for the revs to drop (as the engine revs higher during a cold start to avoid stalling), the owner manual in my 2018 Swift does not recommend idling, had not checked this before!
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Old 17th December 2019, 19:35   #432
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Default Re: Why you must practice the "Idling Rule" with Turbo-Charged Cars

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Originally Posted by ds.raikkonen View Post
Although I do wait for the revs to drop (as the engine revs higher during a cold start to avoid stalling), the owner manual in my 2018 Swift does not recommend idling, had not checked this before!
I always (until now) have “idled” the engine for 30-40 seconds at start. And about 30-40-60 seconds before shut down.

In my Petrol cars, I have always noted what you said above. When the car is started the Revs start at a higher rate. And they drop after a few seconds and calm down, as it were. I usually start moving only after the Revs drop.

However, this particular phenomenon was neither as audible nor as palpably felt, in any of my Turbo Diesel and non Turbo Diesel Vehicles.
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Old 8th January 2020, 18:51   #433
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Default Re: Why you must practice the "Idling Rule" with Turbo-Charged Cars

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Originally Posted by Jeroen View Post
You should read the owner manual and follow to the letter.
Makes sense. Why won't the manufacturer advise something if it is important enough? I took your advice and checked my Ford Figo manual and sure enough don't find anything related to starting. However, there is the below caution on stopping the engine:

Quote:
Vehicles with a turbocharger
CAUTION
Do not switch the engine off when itis running at high speed. If you do, the turbocharger will continue running after the engine oil pressure has dropped to zero. This will lead to premature turbocharger bearing wear.
Release the accelerator pedal. Wait until the engine has reached idle speed and then switch it off.
Looks like idling the engine for certain amount of time before turning it off should add no additional benefit.
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Old 9th January 2020, 11:52   #434
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Default Re: Why you must practice the "Idling Rule" with Turbo-Charged Cars

Well, on the JTP. I wait for the RPM to settle at it's idle speed, and then set off. The car starts and it revs at about 1500 RPM before settling at around 750 RPM which is when I set off.

Similarly while shutting off I let it idle for a while, generally I look out for the sound of the radiator fan shutting down, and then switch the car off, usually around 30 seconds to a minute.
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Old 9th January 2020, 12:26   #435
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Default Re: Why you must practice the "Idling Rule" with Turbo-Charged Cars

Don' know if this was posted here before but I'll just leave this here since it seems relevant:Why you must practice the "Idling Rule" with Turbo-Charged Cars-img_20200109_122243.jpg
A warning from the dashboard of a Mahindra Maxitruck
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