[ramzsys]

Well this is how not to start/stop a turbo diesel.

https://www.youtube.com/watch?v=-zR5IEwiAsE

[rki2007]

Now is it correct to turn off a turbo diesel car in the traffic signal with a wait time of 60 sec or more.

I generally do this for my two wheelers to save fuel, but really don't know whether switching off the turbo diesel engine in a traffic signal and restarting it might cause undue hardship to the turbo.

Can someone please throw some light on this?

[Rahul Rao]

@ rki2007


Lot of previous posts have told us how the turbo functions. So this is what I follow.

!. If I am driving in traffic where I upshift early and generally do not exceed 1500 RPM, I switch off after a 10-15 second wait. But if I have ridden hard and entered the high turbo boost range (starts at 1600 RPM in my VW) then I idle the whole duration.
2. If I am at the beginning of the line, where I might be able to accelerate hard off the mark even then I also stay at idle, but if there are 4-5 cars ahead , and am immediately going to upshift to second I switch off if conditions from 1 have been met.
In multiple cars used and sold by me some even 2 Lakh km and more I haven't faced a turbo failure.

Rahul

[shankar.balan]

Turbochargers are delicate and should be treated with care yes, but they are after all designed to work for the vehicle that they are powering.

As long as one follows the Idle rule at start stop one should be ok.
For one thing, the city commute is so slow that the turbo will rarely spool up to kick in, one is mostly driving on the engine's torque, I find.

[joju]

Originally Posted by vignesh.cv

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

Does any manufacturer fit buses with stop/start system? City buses would benefit tremendously from this, owing to the time they idle to let passengers in and out.

[Rahul Rao]

Scania trucks have stop start system, the system prevents full throttle being applied for 15 seconds after start, and the system can be switched off if sudden power may be needed.

Rahul

[headers]

Originally Posted by rki2007

Now is it correct to turn off a turbo diesel car in the traffic signal with a wait time of 60 sec or more.

I generally do this for my two wheelers to save fuel, but really don't know whether switching off the turbo diesel engine in a traffic signal and restarting it might cause undue hardship to the turbo.

Can someone please throw some light on this?

Would not affect the turbo as long as you are not revving hard. Most Indian Turbo Diesels have a mild turbo and hence the spool is designed to give more torque than power.

Also, the turbos go into idling mode under 1400 odd rpm anyways, hence it would not affect if you stop your engine at traffic lights from crawling speeds.

The Title NEED NOT apply with current engine design and technology upgrade IMHO

Cheers

[amitoj]

Originally Posted by headers

The Title NEED NOT apply with current engine design and technology upgrade IMHO

Cheers

True. Also, I read somewhere that cars like BMW with TwinPower Turbo let the pump run for a while after you shut down the car. Makes sense because these cars now come with a feature wherein the engine actually shuts down when you stop at a red light.

[KkVaidya]

Originally Posted by Vid6639

In case of my Altis, I don't idle before shutting off since it's not a turbo but on a cold start I idle for a minute, drive at low revs for 10mins till the temp needle rises to stable value then drive normally.

It's now embedded. Manson and Rehaan will agree with me

I was just going though this thread and came to your post. Although I am too late on reviewing this after almost 2 years but still I thought let me write.
Well, in case of non-turbo cars, i have read somewhere that letting a cold engine idle for a minute will make more harm then preserve it. Reason being that combustion is best when the engine is at operating temperature (read hot). When the engine is cold, the fuel remains liquid until it is ignited thus causing in-efficient burning. When the cylinder heats up, the fuel turns to vapour immeidatley after it gets injected in the cylinder and thus making it more combustible with air.

That is why modern cars have been programmed to run at higher idle speed (usually 200-300rpm faster then regular) until cylinders get hot. In older generation cars, there was this auto-choke which raised the rpm till the metal strip heats up.

So I believe and recommend to bring the eninge to operating temperature as fast as possible then letting it idle.

[Jeroen]

Originally Posted by KkVaidya

I was just going though this thread and came to your post. Although I am too late on reviewing this after almost 2 years but still I thought let me write.
Well, in case of non-turbo cars, i have read somewhere that letting a cold engine idle for a minute will make more harm then preserve it. Reason being that combustion is best when the engine is at operating temperature (read hot). When the engine is cold, the fuel remains liquid until it is ignited thus causing in-efficient burning. When the cylinder heats up, the fuel turns to vapour immeidatley after it gets injected in the cylinder and thus making it more combustible with air.

That is why modern cars have been programmed to run at higher idle speed (usually 200-300rpm faster then regular) until cylinders get hot. In older generation cars, there was this auto-choke which raised the rpm till the metal strip heats up.

So I believe and recommend to bring the eninge to operating temperature as fast as possible then letting it idle.

The biggest problem with letting the engine idle is that neither the cilinder walls and or the lub oil has the correct temperature. Modern engines, specifically diesels, simply don't warm up when you idle them. You need to load them up.

Check some of my other post where I have written extensively on the experimental testing on oil and wear and tear on the engine i was involved in. Trust mr, idling a cold engine does not do your engine any good, in fact it does it actual harm that can be well measured!

Its not a good idea to idle. Start your engine and drive away carefully, just be cautious of the rpm's and your right foot for the first 5-10 minutes. Its best to get the engine and all of its components up to its normal operating temperature without undue shock. Also, idling an cold engine is extremely bad for the environment.

Check the owner manual, and Im sure it wont tell you to idle, but to act along similar lines as I have just outlined.

Jeroen

[rrsteer]

Originally Posted by Jeroen

Check the owner manual, and Im sure it wont tell you to idle, but to act along similar lines as I have just outlined.

Jeroen

Indded thats what the Toyota Innova owners manual says.

[rrsteer]

I have this small time politician living just opposite my house. I, like many others, just totally detest this guy. He has an Innova which he bought around June 2012 (yeah, I keep an eye on all the cars in my colony. I know most people in my colony through their car and car number)

Now winters in Punjab are quite harsh and you will be amazed to know about his idea of 'warming' up his Innova. Cranks and wrings the poor engine past 3000 rpm and stays at it for quite some time, until he feels satisfied. The innova is not used everyday, but maybe twice or thrice weekly.

Now my question to the experts- how soon can I expect the engine to pack up?

[Jeroen]

Originally Posted by rrsteer

I have this small time politician living just opposite my house. I, like many others, just totally detest this guy. He has an Innova which he bought around June 2012 (yeah, I keep an eye on all the cars in my colony. I know most people in my colony through their car and car number)



Now winters in Punjab are quite harsh and you will be amazed to know about his idea of 'warming' up his Innova. Cranks and wrings the poor engine past 3000 rpm and stays at it for quite some time, until he feels satisfied. The innova is not used everyday, but maybe twice or thrice weekly.



Now my question to the experts- how soon can I expect the engine to pack up?

It wont pack it in at all Im afraid. This is a pretty new Innova and you would be surprised on how much abuse these things can take.

Yes, over time he is likely to wear down in particular the piston rings and cylinder liners, but that will just manifest itself in higher oil consumption. I would be very surprised to see anything really breaking down due to this behavior, even over a long period of time.

Jeroen

[debuda]

Originally Posted by rrsteer

I have this small time politician living just opposite my house. I, like many others, just totally detest this guy. He has an Innova which he bought around June 2012 (yeah, I keep an eye on all the cars in my colony. I know most people in my colony through their car and car number)

Now winters in Punjab are quite harsh and you will be amazed to know about his idea of 'warming' up his Innova. Cranks and wrings the poor engine past 3000 rpm and stays at it for quite some time, until he feels satisfied. The innova is not used everyday, but maybe twice or thrice weekly.

Now my question to the experts- how soon can I expect the engine to pack up?

What this Innova owner is doing is certainly bad for the engine due to the following reasons :

1. When a cold engine is started, all friction surfaces do not have an adequate oil film initially. Also, since the oil is excessively viscous (thick) when cold, it is unable to do its lubricating job optimally till it warms up.
2. By over-revving a cold engine, not only are all mating surfaces being subjected to high frictional forces, all metal parts around the combustion chamber suffer thermal shock.

But the good news is that modern automobile engines are marvels of technology and are designed to withstand a certain degree of abuse. Modern lubricating oils are effective over a very wide range of temperatures. So you are unlikely to see the engine of your friendly neighbour's Innova coming to a grinding halt anytime soon.

The guy who might eventually pay the price for your neighbour's abuse of his Innova is the unsuspecting fellow who will buy that Innova second hand after it has clocked a lakh or two KM. Instead of major engine overhaul required after 3-4 lakh KM, this engine may need to be opened up prematurely after 1.5 lakh KM or so.

[AZ911]

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?