[mdsaif92]

What about cars with turbo and auto stop-start feature? When using auto stop-start the engine is being given hardly any idling time. Can this have a negative effect?

[thoma]

Originally Posted by mdsaif92

What about cars with turbo and auto stop-start feature? When using auto stop-start the engine is being given hardly any idling time. Can this have a negative effect?

Hmm..no doughnuts for your first post without giving a thought about searching. No worries; hope you'll take it in the right spirit. Just wanted to remind you that we have a good search feature on the forum. Maybe this post should help you on your specific query. Welcome aboard!

[apachelongbow]

Idling rule after first start for turbo is to ensure that lubricating oil reaches and lubricates all moving parts of the turbo. Once the engine has idled that 30 secs/1 min and is in use, if it is stopped at say a signal or abrubtly stops, the 30 sec idling rule need not be applied, since the turbo is already lubricated.

The 30 sec idling before a stop is to ensure that after high rpm operations the turbo is given sufficient time to spool down, allowing the bearings to slowdown to a stop and ensure lesser wear and tear of critical components.

Regarding A/C usage just after cranking the car, its a good habit to allow the engine to idle for a short while and not put any load on it, before engine oil has reached all critical components, again useful to preserve the engine for longer.

It is not only turbo charged cars, even bikes like the bullet recommend that the engine be idled for 30 secs or so before applying high loads on it.

[a4anurag]

Originally Posted by apachelongbow

Idling rule after first start for turbo is to ensure that lubricating oil reaches and lubricates all moving parts of the turbo.

The 30 sec idling before a stop is to ensure that after high rpm operations the turbo is given sufficient time to spool down, allowing the bearings to slowdown to a stop and ensure lesser wear and tear of critical components.

The idling rule is for the whole engine and its lubrication focusing more on the Turbocharger as it the most critical and sensitive part of the engine. It is not cheap either to replace. That is why the engine revvs a bit higher upon cranking and slowly settles down to idle so that all the parts get the engine oil.

Post a hard drive (Heavy foot) the turbo will be spinning at a very high RPM so the heat generated too will be high. If the engine is switched OFF instantly the oil around the shaft will start forming cakes and in turn fail the turbocharger. The idle will help the temperature to decrease and spinning of the turbo will also come to minimal.

Cheers,
Anurag.

[thoma]

I might be stupid with this query, but I could not find out at what RPM the turbo kicks in for the Micra dCi.

Does it mean that the turbo spools right above idle and that the turbo is a one with very low inertia? Does that also translate to 1) because of less inertia, the turbo spools down quick enough to bring down a 60 sec idle before shutdown? OR 2) the turbo spools even at crawling speeds for entering the garage and that the 60 sec idling is much apt?

P.S: Though the owners manual does not mention anything on idling before shutdown, I go by what the thread suggests. But at some places, like right in front of a shop or at a guest's garage, it feels a bit embarrassing to keep the engine on for a minute.

[a4anurag]

Originally Posted by thoma

I might be stupid with this query, but I could not find out at what RPM the turbo kicks in for the Micra dCi.

Does it mean that the turbo spools right above idle and that the turbo is a one with very low inertia? Does that also translate to 1) because of less inertia, the turbo spools down quick enough to bring down a 60 sec idle before shutdown? OR 2) the turbo spools even at crawling speeds for entering the garage and that the 60 sec idling is much apt?

P.S: Though the owners manual does not mention anything on idling before shutdown, I go by what the thread suggests. But at some places, like right in front of a shop or at a guest's garage, it feels a bit embarrassing to keep the engine on for a minute.

30 sec idle is needed if the car is driven hard. Not for small drives.

The turbo may be spooling at 1800 - 2000 rpm.

It is better to idle whatsoever it happens as it would keep you in peace later too.

[rajshenoy]

Not sure if this question has been asked. Also i drive petrol cars so not much technical knowledge of Diesels.

For getting Best fuel efficiency, Maruti gives tips such as Switching off the Engine at signals(Mahindra MicroHybrid does it automatically isnt it?) Now, if the signal lasts 60-90 seconds, What should the Diesel car owners do ? Since the Topic says 30-60 min idling before and after engine is on/off

[mahesh.kolary]

Originally Posted by rajshenoy

Not sure if this question has been asked. Also i drive petrol cars so not much technical knowledge of Diesels.

For getting Best fuel efficiency, Maruti gives tips such as Switching off the Engine at signals(Mahindra MicroHybrid does it automatically isnt it?) Now, if the signal lasts 60-90 seconds, What should the Diesel car owners do ? Since the Topic says 30-60 min idling before and after engine is on/off

Well, this particular query has already been addressed in this thread.

Originally Posted by thoma

Hmm..no doughnuts for your first post without giving a thought about searching. No worries; hope you'll take it in the right spirit. Just wanted to remind you that we have a good search feature on the forum. Maybe this post should help you on your specific query. Welcome aboard!

[rajshenoy]

Originally Posted by mahesh.kolary

Well, this particular query has already been addressed in this thread.

Thanks, Could not search it earlier since it had long list of answers. So far Diesel car owners need not have turned off their engines since it was petrol which was so expensive.

Now with Increasing petrol prices, people might feel the pinch. Also i have seen Rash taxi drivers turn off the engines(May be they graduate from Autos) and then zip off again once the signal turns amber !!

[mahesh.kolary]

I guess idling comes under Good practises/Guidelines.
The taxiwallah's may or may not be aware of the problems that rapid acceleration on engine coldstart is going to produce. Still,the chance a taxi driver is going to follow the idling rule is very minute unless he happends to be a good BHP'ian.

[999]

Originally Posted by mahesh.kolary

I guess idling comes under Good practises/Guidelines.
The taxiwallah's may or may not be aware of the problems that rapid acceleration on engine coldstart is going to produce. Still,the chance a taxi driver is going to follow the idling rule is very minute unless he happends to be a good BHP'ian.

From what I have seen , they know their car much better than most normal people do. Mostly learned from experience. Also drivers were predominently seen to care for their car, other than the rented car taxi drivers.

[rajeev k]

Yesterday came across a professional driver who was raising the engine rpm like hell several times, before he stopped and parked the Mahindra Verito for the day. Tried to convince the owner about the harm this can cause and asked him to educate his driver.

[karan561]

Originally Posted by Vid6639

Have you tried to see after a spirited run if the start/stop works and switches off the engine immediately. I would think that the start/stop would not work when the engine has been worked hard.

Originally Posted by Rehaan

Would be interesting to see if a higher limit temperature is also specified, after which the start-stop disables itself. Will wait to hear back from you, but i wonder if you'll be able to hit that limit!

Originally Posted by karan561

Frankly not sure about this. Because most of the times the start/stop is kept off

Will try it out in the next run & report back

There have been many instances where in the car has come to an hault even after extremely spirited runs but never has the car " not shut down ", it always did !

Only when recently when my OT (Outside Temperature) sensor had failed & OT was shown as -40 Degree C, the Start/Stop system went in-active.
Which made me conclude it is temperature sensitive both negative as well as it wont work if the temperature exceeds +35 Degree C

Also heres a small list of reasons from the manual about why & when the Start/Stop system may not work or remain in-active;

- The car is coasting (manual transmission)
- Brake vacuum reading is too low (manual transmission)
- Insufficient brake pedal pressure is being applied to hold the vehicle stationary (automatic transmission)
- Stopping on a hill/downhill with a 12% or greater gradient
- If the steering angle is more then 6 degrees
- If the steering wheel is still be moved after approximately one second of coming to a stop
- The system has not yet be activated by going over a speed of 5mph for automatics, 3mph for manuals since the last engine switch off
- If the gas pedal is being pressed (engine must be at idle speed only)
- You're coming to a stop from reverse
- The driver gets out of the car
- If Hill Decent Control (HDC) is activated
- If the engine is not up to temperature
- If the carbon canister is being purged
- If the grade of the fuel is too low for the engine
- Transmission adaptation is active (automatic transmission)
- The hydraulic pressure accumulator is not yet up to pressure (automatic transmission)
- Stop-and-go traffic - system is only activated by driving over 5mph for automatics, 3mph for manuals
- Batter charge is low
- Outside temperature is colder then 37.4 F / 3 C
- Outside temperature above 95 F / 35 C and the air conditioning system is on
- Fogging of the windshield is detected by the IHKA system
- Climate control system is on but passenger compartment has not yet reached desired temperature
- ABS system was used when coming to a stop

[mahesh.kolary]

Originally Posted by 999

From what I have seen , they know their car much better than most normal people do. Mostly learned from experience. Also drivers were predominently seen to care for their car, other than the rented car taxi drivers.

Well, I shouln't have generalised. My bad.
I personally know taxidrivers who take good care of their baby,even giving them names.
Most of the drivers know from their experience what's gonna cause harm, and what's gonna do good. An issue like turbo failure need not be immediately attributed directly to non-conformance of the idling practise. Moroever this is a good practise, not a hard and fast rule for most manufacturers. This oversight can result in premature turbo deaths especially in cases like this.

Originally Posted by rajeev k

Yesterday came across a professional driver who was raising the engine rpm like hell several times, before he stopped and parked the Mahindra Verito for the day. Try to convince the owner about the harm this can cause and asked him to educate his driver.

[Reinhard]

Originally Posted by thoma

I might be stupid with this query, but I could not find out at what RPM the turbo kicks in for the Micra dCi.

Does it mean that the turbo spools right above idle and that the turbo is a one with very low inertia? Does that also translate to 1) because of less inertia, the turbo spools down quick enough to bring down a 60 sec idle before shutdown? OR 2) the turbo spools even at crawling speeds for entering the garage and that the 60 sec idling is much apt?

P.S: Though the owners manual does not mention anything on idling before shutdown, I go by what the thread suggests. But at some places, like right in front of a shop or at a guest's garage, it feels a bit embarrassing to keep the engine on for a minute.

You may already have figured out the answer considering your post is pretty old now, but I'm answering it partially anyway -

The turbo is spooling up (i translate it as - generating enough compression to actually make a difference to the engine performance) at the RPM where your car delivers maximum torque / power. I'm sure the documentation will mention something like this - Max Torque = 190 Nm2 - 1750 to 3000 RPM. (Just random numbers used) which means, your turbo is spooling at 1750 RPM.

Regardless of spooling up, the turbine does spin anyway with the exhaust gases - just that at lower RPM, the quantity & rate of exhaust gas created isn't enough to spin it fast. So the turbo-RPM is less, and the air isn't compressed enough to create a boost in the engine.

As a4anurag & many others mentioned, its not a necessity to idle if for the last minute or more, you have driven at lower RPM than the turbo-spool RPM. That is significantly near idling RPM anyway as far as the Turbo is in question.

Don't worry much about the embarrassment. On our roads, not many have time to notice us anyway. And, the embarrassment if any, is worth the long turbo life