[SS-Traveller]

One more point to add, though partly off-topic:
Turbocharged diesels do not like being driven for short distances on low rpm without warming up through and through. Apart from many other issues, the turbocharger oil seal is also affected due to the fuel-rich exhaust not clearing out till the turbo heats up and spins fast enough.

Bottom line: Don't take your turbo-charged diesel car to the market 1.5km away everyday. An occasional trip is fine, but if your car only does this 1.5km trip every day, you are better off getting a naturally aspirated petrol engined car for your purposes.

[vikram_d]

Strangely enough I have not seen people talking about oil cooled vs water cooled turbos in this thread. Water cooled turbos do not suffer from coking. Only oil cooled turbos do. Are all our OEM turbos oil cooled? If they are then they need to be spooled down but not if they are water cooled. Mazda had done some research on oil cooled vs water cooled turbos. The results are pretty clear in the attached photo.



So the point of my post is that it would help greatly if we knew what vehicles are being sold with what kind of turbos.

Source: http://www.rx7club.com/single-turbo-...turbos-966424/

[akshay4587]

Originally Posted by vikram_d

Strangely enough I have not seen people talking about oil cooled vs water cooled turbos in this thread. Water cooled turbos do not suffer from coking. Only oil cooled turbos do. Are all our OEM turbos oil cooled? If they are then they need to be spooled down but not if they are water cooled. Mazda had done some research on oil cooled vs water cooled turbos. The results are pretty clear in the attached photo.

Attachment 1044690

So the point of my post is that it would help greatly if we knew what vehicles are being sold with what kind of turbos.

Source: http://www.rx7club.com/single-turbo-...turbos-966424/

AFAIK Linea T-Jet comes with a Water cooled Turbo,where as the one on MJD is the usual one.

[Rehaan]

Originally Posted by vikram_d

Strangely enough I have not seen people talking about oil cooled vs water cooled turbos in this thread.

Quite a few mentions of it on the last page of discussion itself. This does make a big difference, but you also cant deny that it would still be advantageous to cool-down before shutting down (though not to the same degree as an oil-cooled turbo).

I'd like to add another one to the mix : what about ball-bearing turbos?

cya
R

[vikram_d]

Originally Posted by Rehaan

Quite a few mentions of it on the last page of discussion itself. This does make a big difference, but you also cant deny that it would still be advantageous to cool-down before shutting down (though not to the same degree as an oil-cooled turbo).

I'd like to add another one to the mix : what about ball-bearing turbos?

cya
R

Ball bearings seldom suffer from coking as the rolling action of the balls erodes away the coking. But an important point to be noted, most commercially available ball bearing turbochargers are water cooled. Need to do more research on why this is.

[oxyzen]

Originally Posted by GTO

• Be gentle to your car when she's cold. Maintain a low rpm level (below 2,000) until the engine has reached operating temperature. The oil is cool / cold and its pressure is lower too.

EDIT- In cold conditions oil pressure is significantly higher. At idling the oil pressure can be even 5 bar at 20°C. However at warmed up cond (~100°C) it can come down to below 1 bar.

High revving during this time can cause certain issues as it will take the oil pressure even higher.

[90BHP]

Thanks for the advice GTO, can you also state if the surrounding temperature can have an impact on this performance ? Should we increase or decrease the time if we are in a colder environment. Apart from the normal idling required to warm up the engine in this period.

[rakesh_r]

GTO- very useful and informative . Following the idling rule judiciously for the past 2 years in my swift D.During the last end of the journey about 2 km before shut down i switch OFF the AC and only let the blower,keep the revs below 2K and at the parking lot idle for 2 min before shut down.In traffic signals I normally don't shut OFF the engine.A couple of months back i happen to see a turbo failure in a Swift D and believe me its not a good sight to see with the engine running amok with the smoke bellowing from the car like a fumigator and the drama ending with a BANG.All i could see was the owner running frantically for help as no one had a clue what was happening.

[Hayek]

Originally Posted by Rehaan

Bombay style stop-go wouldn't really be high load, except perhaps the first 1 second when you release the clutch and move your car from a standstill.

High load is : climbing a hill, heavy acceleration, car full of people, etc.

the sooner you get up to operating temperature, the better it is for the environment.

Thanks for the inputs. This is a big relief, as I was concerned that I had been abusing my car . My plan going forward is as under:

1. At start up, keep moving but with gently accelerator inputs. Given the traffic conditions near my house, I would hardly every cross 2000 or 2500 rpm in any case.

2. Return journeys in Bombay traffic - be a little more careful to ensure that I don't cross 2000 rpm for the last 2-3 minutes of my drive

3. Highway journeys, which involve high speed driving - if the low speed run prior to a halt is less than about 3 minutes, idle the engine for about 1-2 minutes before turning the engine off

I was very concerned about the need to idle for 2 minutes on every trip. Why? Because my car consumes between 1-1.5 litres per hour, and given that I make 4-5 journeys per day, this would imply a need to "waste" fuel for almost 10 minutes a day, or a litre every week. While that is not much compared to the cost of a burst turbo, if careful driving for the last 2-3 minutes is enough to avoid it, that is a far better deal.

[supertinu]

Good focused thread on this topic. What surprises me is that an avg car owner with not too much interest on technical details are virtually unaware about turbos and idling. Couple of my colleagues at work were surprised when I mentioned it to them. Even the sales guys or service advisors at A.S.S dont seem to be educating people enough. Manufacturers need to ensure that dealerships educate there customers about these facts.

On my Figo user manual also it clearly mentions that idle for about a min before switching off the engine but not once did the sales guy ever mentioned it when i was buying nor during service time.

In some cars like the Mahindra Thar there is sticker on the dash which say idle for 1-2 mins before you switch off the engine.

In my daily routine in the morning I usually start my car and then put my bag in the boot, drop the wipers down left high by the cleaner. That usually allows atleast 30sec of idling and during parking I normally listen to some music 30-60 sec before switching off the engine. At work its little weird at times cause the security guy keeps on waiting for me to get off the car to wish good morning and I continue sitting inside after parking .

[dkaile]

I have been following the idling rule for both my Superb and the Fortuner quite religiously, at least at start-up, as I normally don't do hard driving to warrant an extended cool-down.

The Superb (1.8 TSI MT) on start-up starts at a high ECU controlled rpm of around 1100 rpm. The engine too shudders a wee bit initially. Within a few seconds, the rpm drops to around 750 (780 in cold weather) and the engine starts smoothening out all by itself. I drive at lower rpm's for the initial few minutes till the engine temperature reaches the desired 90 degrees point. I usually don't require a extended cool down with this petrol engine, though I do follow a cool down procedure with the diesel Fortuner after a extended drive.

I always knew that idling is good for the engine at start/stop but thanks for the extended information GTO.

[vikram_d]

I would like to add another point to this discussion. Fully synthetic oils are less prone to coking than mineral oils as they can withstand higher temperatures and not break down at high temperatures.

[s.prashanth]

i bought a altis diesel recently, Do also need to folow the cooling down and start up procedure??. When i asked the service manager he said it was not required. Please advice

[Vid6639]

Originally Posted by s.prashanth

i bought a altis diesel recently, Do also need to folow the cooling down and start up procedure??. When i asked the service manager he said it was not required. Please advice

Yes ofcourse. It's a turbo diesel with a small displacement engine and a turbo running at higher boost to get decent performance. If your driving on a highway or driving at higher rpm's for longer periods you should follow the idling rule.

The Altis turbo is also not one of the most reliable ones so all the better.

[issigonis]

>>>

Have been idling for about 60-90 secs at start and end of journeys all through.
To use up the time spent in the car, I text messages or make important phone calls, especially as my office basement has good coverage.

The security guards unaccustomed to seeing people sit in the car after it has been parked give curious glances, but are sort of re-assured when they see me talking on the phone.

Very useful thread.

Regards