[rovingeye]

Just this morning, while going through the Tata Hexa thread, I came across this picture. So, it would seem that the one minute warm up rule still applies.

[saket77]

Originally Posted by rovingeye

Just this morning, while going through the Tata Hexa thread, I came across this picture. So, it would seem that the one minute warm up rule still applies.

You missed the keyword there: Turbocharged.

[swissknife]

Originally Posted by saket77

You missed the keyword there: Turbocharged.

unstoppable's car seems to be a turbocharged one. Hence it does seem applicable. I do wait for the RPM to drop from 1100 K to about 800, during the morning starts. At other times, the time that I take to strap up, open the OVRMs, etc is time that there engine is let to idle. I generally keep the revs as low as possible as I near the location where I need to stop/park as well.

[unstoppable]

Thanks that helps!! So there seems to be no right or wrong ans to this question. More or less I see its people practice then an must do procedure.

[R2D2]

Whether NA or turbocharged I always idle the engine for 1-2 minutes after cold start i.e. switched off overnight or longer.

With my NA car I follow a 1-2 minute idle after a run at highway speeds. I do away with the idle-before-shut-off rule if the car has run at low RPM for e.g. in city limits with stops at traffic lights.

With turboed engines this idling rule before start up and shutdown is even more crucial to prevent premature turbo problems. This rule is applicable no matter the duty cycle and must be followed religiously.

[unstoppable]

Originally Posted by Simhi

Some of the threads you can refer to

https://www.team-bhp.com/forum/techn...-vehicles.html (Idling Time during Morning Start for MPFI Vehicles)
https://www.team-bhp.com/forum/techn...rged-cars.html (Why you must practice the "Idling Rule" with Turbo-Charged Cars)

Mods, kindly merge this thread with appropriate one

Thanks a lot for the share!!! I guess there is no hard and fast rule to do this but more of people personal choice these days.

Originally Posted by R2D2

Whether NA or turbocharged I always idle the engine for 1-2 minutes after cold start i.e. switched off overnight or longer.

With my NA car I follow a 1-2 minute idle after a run at highway speeds. I do away with the idle-before-shut-off rule if the car has run at low RPM for e.g. in city limits with stops at traffic lights.

With turboed engines this idling rule before start up and shutdown is even more crucial to prevent premature turbo problems. This rule is applicable no matter the duty cycle and must be followed religiously.

So do we primarily see this a need only for turbocharged engine or any sort of engines both petrol and diesel?

Originally Posted by rovingeye

Just this morning, while going through the Tata Hexa thread, I came across this picture. So, it would seem that the one minute warm up rule still applies.

Attachment 1825662

Good catch!!! I am sure this kind of sticker is there somewhere on my car as well.

[feluda86]

What about idling at longish traffic signals? What is an optimum idling time for a car? In cities, longish signals are very common and frequent. What is the recommendation for such cases - leave the car to idle at these signals or idle for 1-2 minutes then turn off for every such signal?

[Santoshbhat]

Originally Posted by rovingeye

Just this morning, while going through the Tata Hexa thread, I came across this picture. So, it would seem that the one minute warm up rule still applies.

Attachment 1825662

Pity a company like Tata does not proof read. Apart the obvious spelling mistake, what a crude way to convey the message! "Atleast one minute after starting and also before stopping" conveys the wrong meaning. They should have mentioned one minute after starting engine/ turning on ignition and one minute before turning off engine/ ignition, if that is what they mean.

[R2D2]

Originally Posted by unstoppable

So do we primarily see this a need only for turbocharged engine or any sort of engines both petrol and diesel?

It is a must for petrol or diesel turbocharged engines. For NA engines it is at your discretion but as mentioned below I choose to let the engine idle for 1-2 minutes before shut off after a highway run for e.g. if I have to stop for a bio break or a snack/meal at a roadside restaurant.

Originally Posted by feluda86

What about idling at longish traffic signals? What is an optimum idling time for a car? In cities, longish signals are very common and frequent. What is the recommendation for such cases - leave the car to idle at these signals or idle for 1-2 minutes then turn off for every such signal?

Environmental and fuel conservation guidelines recommended you shut off the car if the signal is >10 seconds which IMO is rather ridiculous. For e.g. here Engine switched off at traffic signals

But I choose not to for different reasons including preserving the expensive starter motor and battery plus the having the added comfort of the car AC. I would disable the stop-start system of modern engines. I prefer not having any car system taking control away from me and also for the fact that I need the engine ready to go at all times when I am on the road even at traffic signals. But in the end it is your call.

[unstoppable]

Originally Posted by R2D2

It is a must for petrol or diesel turbocharged engines. For NA engines it is at your discretion but as mentioned below I choose to let the engine idle for 1-2 minutes before shut off after a highway run for e.g. if I have to stop for a bio break or a snack/meal at a roadside restaurant.

Basically I now understand that at least its a must for my car as its turbocharged. Thanks all. Irrespective of who is doing it or not I am continuing this practice as I do not see any harm this.

[typlo]

There are different opinions about this on the internet (just like those for proper engine break-in).

I am an Automotive Engineer. From a purely scientific perspective, it is necessary to wait a little to get the oil flowing through a turbo because oil has to do the job of cooling as well as lubricating the bearing. Keep in mind that the turbo spins extremely fast; the wear and tear when the lubrication is not optimum is accelerated.

It won't hurt to wait a little, just like you'd do for a naturally aspirated car on a cold start. I'd say give it 20-30 seconds before driving off. Use that time to fasten the seatbelt, adjust mirrors and other minor tasks. Anything beyond that is a waste of time and fuel.

The more important point to be noted here is, take it easy on the car when the engine is cold. As mentioned in a Team-BHP thread somewhere, take it easy for the last few miles of your drive too. Idle for 15-20 seconds before turning the ignition off. You can be conservative with the idle time but here's what I'd do.

[Rshrey22]

Scotty Kilmer's at your rescue!

https://youtu.be/MEaYKmxk_yc

[ashwinprakas]

Just to add, for air cooled engines you should idle the motor for a minute but not more than 2 as it could result in accelerated wear and tear, recall reading this in one motorcycle owners manual a while ago.

[Jeroen]

Originally Posted by typlo

I am an Automotive Engineer. From a purely scientific perspective, it is necessary to wait a little to get the oil flowing through a turbo because oil has to do the job of cooling as well as lubricating the bearing. Keep in mind that the turbo spins extremely fast; the wear and tear when the lubrication is not optimum is accelerated.

Have you ever tested how long it takes for all components in a car engine to get proper lubrication after starting? Or calculated it by looking at the capacity of the oil pump, versus the volume of the various oil lines, etc to be filled?

Jeroen

[typlo]

Originally Posted by Jeroen

Have you ever tested how long it takes for all components in a car engine to get proper lubrication after starting? Or calculated it by looking at the capacity of the oil pump, versus the volume of the various oil lines, etc to be filled?

Jeroen

Mostly, calculations involving the flow rate and standard orifice diameters. Of course my point won't stand true for the different shapes and sizes of components we have in vehicles from different makes but 30 seconds is still very conservative because 30 seconds is a long time in terms of engine or its components running without lubrication and no designer/engineer would risk that. The lubrication starts as soon as you start up your engine and oil takes merely seconds to reach your turbo. The flow rate stabilizes over the next 10 seconds or so. You're good to go. Keep in mind you're still not at operating temperature.

The manufacturers have taken into account all of this but haven't bothered to update the manuals because most people would find it confusing. So they stick with the 1-minute rule. Taking it easy on a cold start holds much more weightage for the longevity of your power train.

If you want to see some tests, you could fire up youtube and go to the channel 'Engineering Explained' or 'Motorcyclist Magazine' and 'Scotty Kilmer', they have covered this topic in whole breadth. Team-BHP itself has a very nicely articulated article on this (Why you must practice the "Idling Rule" with Turbo-Charged Cars) as well and I'd say the metrics mentioned in this article are mostly conservative and things tend to get easier for intercooler affixed turbos (common for newer cars) and water-cooled turbos (rare).