Team-BHP - Why you must practice the "Idling Rule" with Turbo-Charged Cars

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Originally Posted by AZ911 (Post 3685839)

I'm not sure whether this question has already been tackled here or not, but I was wondering that some TC'ed cars have this auto engine cutoff feature like in BMW. If idling rule applies to these cars, isn't it a self detrimental feature implementation by BMW?

No, its designed that way. The idling rule is (becoming) a thing of the past. Always check your manual, if it requires idling, the manual will state so. If not, it was designed without the need for idling.

Jeroen

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Originally Posted by AZ911 (Post 3685839)

These modern expensive cars don't have Oil cooled turbos so don't need idling to cool off those bearings.

Quote:

Originally Posted by AZ911 (Post 3685839)

I was wondering that some TC'ed cars have this auto engine cutoff feature like in BMW. If idling rule applies to these cars, isn't it a self detrimental feature implementation by BMW?

If you hammer these cars at high speeds for some time, and immediately stop, they do not switch off immediately, rather after 20-30 seconds. But they usually tick over at at 1500 Rpm at low high way speeds like 80 kph, and if you stop then they switch off almost immediately.

Rahul

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Originally Posted by KkVaidya (Post 3686088)

These modern expensive cars don't have Oil cooled turbos so don't need idling to cool off those bearings.

Aren't these intercoolers? They are meant to cool down the air coming from the turbo before being fed to the engine. So I am guessing the modern expensive cars also require the "idling practice"

Quote:

Originally Posted by technoslerphile (Post 3718260)

Aren't these intercoolers? They are meant to cool down the air coming from the turbo before being fed to the engine. So I am guessing the modern expensive cars also require the "idling practice"

No Intercoolers don't need any idling as their purpose is to cool the inlet air going into the turbo. It is the turbine that needs to cool off before being shut down.

I'll be honest here, I've found the opinions on this thread massively confusing!

Having bought my first diesel hatch, I started reading this thread.

But instead of getting clarity on whether one should idle their engine for 30 seconds or not, all I've understood is that no two people on this thread have the same opinion :uncontrol

Fellas, a clear suggestion please. Should one idle for 30 seconds before starting off & shutting down? A simple YES or NO would suffice.

The car in question is a Hyundai i20, manufactured June 2015.

Quote:

Originally Posted by sourav9385 (Post 3741905)

Fellas, a clear suggestion please. Should one idle for 30 seconds before starting off & shutting down? A simple YES or NO would suffice.

Yes, one should idle before starting off and before shutting down to protect the turbo.

Quote:

Originally Posted by sourav9385 (Post 3741905)

Fellas, a clear suggestion please. Should one idle for 30 seconds before starting off & shutting down? A simple YES or NO would suffice.

I suggest you have a look in the Owner's Manual for the manufacturer's recommendations. The manual for my car (Skoda Octavia TDI) says the following:

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Do not warm up the engine while the vehicle is stationary. If possible, start your journey as soon as the engine has started. Through this, the engine reaches its operating temperature faster.

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Do not switch the engine off immediately at the end of your journey after the engine has been operated over a prolonged period at high loads but leave it to run at an idling speed for about 1 minute. This prevents any possible accumulation of heat when the engine is switched off.

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Originally Posted by StarrySky (Post 3742132)

I suggest you have a look in the Owner's Manual for the manufacturer's recommendations. The manual for my car (Skoda Octavia TDI) says the following:

Does the manual refer to keep the car under certain RPMs after starting a cold engine? As keeping the engine idle or start driving at low revs are both safe for the Turbo.

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Originally Posted by KkVaidya (Post 3743144)

Does the manual refer to keep the car under certain RPMs after starting a cold engine? As keeping the engine idle or start driving at low revs are both safe for the Turbo.

The manual does not mention any particular RPM, but cautions:

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Avoid high engine revolutions, full throttle and high engine loads before the engine has reached its operating temperature – risk of damaging the engine!

In my observation, the engine does not reach its operating temperature as defined by the manual (i.e., temperature needle in the mid-range of the guage) even in 2 or 3 minutes. Most days when I reach office in the morning after a 6km drive at speeds upto 50kmph, the temperature guage reaches barely above 50. So really, 30s or even 60s of idling before starting off also does not mean I am free to drive as I please as soon as I am off. I would much rather drive, albeit slowly, as the engine is warming up.

Wonderful article and thread. Something like this was definitely needed and it is sad to see this thread not being read/posted to anymore.

In my 2005 scorpio a sticker was pasted on the steering wheel for a 1 minute idle during start and shut down. I followed this religiously during all starts/shut downs even if it was during the middle of the day or I had to park for only a few minutes and get going again.

The car ran for about 3 lac km before I sold it off, and last I heard the new owner also was running it without any engine troubles so I guess turbo cooling definitely is a must.

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Originally Posted by rajivrt (Post 3767947)

Well, for your car it was. More and more cars and engines don't require it. When in doubt check the manual.

Most owners haven't got a clue and mist get away with it with no problem. But better safe than sorry is a good approach

Jeroen

Thanks for the thread, I didn't know about this. The more I live the more I learn.

In normal sedate city driving conditions, I switch off the engine at red lights if I have to wait for more than 20 seconds. Which means I do not really cool down the engine before switching off. Is this fine? I believe cooling down is necessary only if you are into hard driving like climbing hills or high-rev or plain long hours of driving. Please educate me on this.

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Originally Posted by Sudipto-S-Team (Post 3768151)

Yes. I have owned and driven Diesel Turbo charged vehicles since 2008.
I do not switch off at red lights unless the wait is going to be very long.
I place the gear lever in neutral and sit with the AC on and music on.

However, if I were to drive the car a little faster or climb up a hill or something where the Turbo is spooling up a lot, then when I reach my destination, I allow the vehicle to cool down slowly over a couple of minutes and then switch off.

Even in normal city use up and down from work, even though the progress is mostly of the start-stop variety, when I reach my destination, I always allow the vehicle to idle for a minute or so before switching off completely. At the time of starting up the vehicle, I allow it to idle for a minute or so before engaging gear and moving off.

I do drive sedately - no space in these crowded cities for "spirited" driving.