[rohittunga]

I have a weird question here. Assume that you are driving on the road and ahead lies a Traffic Signal. Seeing that there is green light, we normally tend to increase our speeds marginally to make it through. Now just as you are about to cross the signal, you get the red light and that too for 100 sec.

Now all along we were told that if the duration of the signal is more than 60 sec, it is always better to switch off. HOWEVER, keeping in mind about turbo idling (and the fact that you drove quickly to make it through), the best practice is to idle for 60 sec and then turn off. But it doesn't really make any sense to switch off for only 40 sec.

Therefore what we incur from this scenario is to keep the car idling throughout the 100 sec. Also since most cars these days are diesel and turbocharged, if all of them are going to follow this method, then a lot of extra fuel is going to be burnt.

Catch 22 situation indeed

[GTO]

Originally Posted by ad75

how effective the turbo timers are.any users here?

As mentioned in the article, we'd recommend that you idle the car yourself, instead of adding a new component to the mix.

Originally Posted by F50

1) City runs - Idle for 3+ mins on cold starts.

2) Highway run - Idle for 7+ mins on cold starts and cooling down for 5 mins.

I'd say this is excessive. 30 - 60 seconds on regular days, with 2 minutes at the end of a fast highway run should suffice.

Originally Posted by gandalf

So wouldnt driving the car for the initial 2 minutes and the final 2 minutes @ lower RPMs (below the turbo spooling levels) do?

Sure would. Just throw in a handful of seconds of idling if you intend to stay at very low rpms at the start / end of your journey.

Originally Posted by vnabhi

Nevertheless, I've made it a point to idle my petrol cars for around 15 seconds before logging off.

Warm-up is essential for n/a petrols, but idling isn't required before shutdown. I don't cool down the Civic (the only petrol in my garage) or the Jeep (only non-turbo diesel) at all.

Originally Posted by akshay4587

AFAIK Linea T-Jet comes with a Water cooled Turbo

Yup, believe so. I read this on Team-BHP itself.

Originally Posted by oxyzen

EDIT- In cold conditions oil pressure is significantly higher.

Thanks . Removed that line from the post.

Originally Posted by vikram_d

Fully synthetic oils are less prone to coking than mineral oils as they can withstand higher temperatures and not break down at high temperatures.

Yet another reason to use synthetic over regular oil.

[zenren]

Originally Posted by GTO

I'd say this is excessive. 30 - 60 seconds on regular days, with 2 minutes at the end of a fast highway run should suffice.

Sure would. Just throw in a handful of seconds of idling if you intend to stay at very low rpms at the start / end of your journey.

Wouldn't most cases actually involve driving at low rpms in the beginning and end of the journey, since getting in or out of parking lots would have to be done under the turbo spooling levels anyway?

Originally Posted by rohittunga

I have a weird question here. Assume that you are driving on the road and ahead lies a Traffic Signal. Seeing that there is green light, we normally tend to increase our speeds marginally to make it through. Now just as you are about to cross the signal, you get the red light and that too for 100 sec.

Now all along we were told that if the duration of the signal is more than 60 sec, it is always better to switch off. HOWEVER, keeping in mind about turbo idling (and the fact that you drove quickly to make it through), the best practice is to idle for 60 sec and then turn off. But it doesn't really make any sense to switch off for only 40 sec.

The practice you have mentioned is just potential recipe for disaster. Personal experience is that if i see a green signal ahead, there is a high chance it would have turned yellow/red by the time I reach it and would be forced to stop. So it is better to slow down gradually instead of increasing the speed and then braking suddenly in case signal turns red inviting a rear end collision.

Always slow down when you are entering an intersection, irrespective of whether the light is red or green. In case there is an emergency vehicle crossing you, it has the right of way irrespective of your signal and you should always be in a position to stop and let it pass. If your speeds are on the higher side, you might still be able to sudden brake and stop somehow but the vehicle behind you might not be able to do the same.

Coming back to the topic of switching off the turbo engines at signals, most cars these days are run with AC on and you would start to sweat by the time the 100 seconds pass if you switch off the engine and AC. Also, if you are on a stretch with multiple signal points, over revving and sprinting from one signal to the next is not going to give you much savings in time either when compared to sedate driving.

[vnabhi]

Originally Posted by vnabhi

Nevertheless, I've made it a point to idle my petrol cars for around 15 seconds before logging off.

Originally Posted by GTO

Warm-up is essential for n/a petrols, but idling isn't required before shutdown. I don't cool down the Civic (the only petrol in my garage) or the Jeep (only non-turbo diesel) at all.

Agreed, but some Fiesta owners like yogi1977 had an issue with the car when it was stopped soon after a high-speed drive. As far as I remember, they found it difficult to start the car.

Even I faced an issue once after a high-speed drive. I switched off the engine at a roadside dhaba soon after reaching it. A few seconds later, I spotted a better place to park the car. So after re-starting the car, while reversing around 100 meters to the new spot, I found the tacho moving from 1000 rpm to 2200 on its own, without any throttle input !

After that, I've started idling for around 15 seconds, and never faced that issue again. I'm not sure what caused it, as it was a one-off case.

[BinFord]

Hi All

My practice is that before reaching home ,I slowdown from the main road since I have small slope from main road to the service road to house and put the gear to neutral .After this I need to drive for 2-3 minutes before my gate. But all these less than 1500 RPM. Then I do a reverse and park the car and keep it idle for few seconds and switch off the engine.

Is this advisable or not?

[Vid6639]

Originally Posted by vnabhi

After that, I've started idling for around 15 seconds, and never faced that issue again. I'm not sure what caused it, as it was a one-off case.

This used to happen on my Lancer petrol very rarely. I narrowed it down.

Whenever I switched off the engine and the radiator fan was running, it would not start easily after a few minutes. After that I started to check if the fan was on or off before turning off the car. If it was on, I would wait for the fan to cut off then switch off the engine. The few times I turned off when the fan was running, the car would start after a bit of extra cranking. I think it had something to do with the idle air control valve that slightly increases the rpm when the fan comes on since when the fan comes on, it loads the engine.

[vivekn83]

A Fantastic Article, I religiously follow the idling exercise as it is a Must and Should for me.
I park my i20 CRDi in the basement garage, which has a very steep incline (almost 40 degrees). Getting the vehicle out is no mean task as I feel the garage entry/exit design is flawed. It is actually a flat flooring followed by that steep incline. Hence I make sure I keep the engine idle for a minute or 2 to begin with and then slowly motor it towards the incline where I will have to stop just to ensure that the vehicle doesn't graze the incline. Then I will have to rev the engine up until 1700 RPM and then take off on the slope, from a complete standstill, which is very much enthralling

I just hope this has no bearing on the engine on a long run

[Jeroen]

Interesting article.
There are quite a few turbo engines on the market that dont require any cool down period at all. So just check the manual, if it doesn't say anything there is no need. It wont hurt to do so, but its not useful either. If it makes you feel better, by all means keep doing it.

The various VW and Audi diesel that I drove before moving to the US in 2009 were all turbo charged and did not require any special attention after starting or prior stopping the engine. Other than the usual caution on a cold engine ; start, drive away immediately but try and avoid high load and high RPMs until the engine has reached its proper normal operating temperature. That is more to reduce engine wear than to reduce potential turbo wear.

Jeroen

[satish_appasani]

Thank you @GTO and others for the insightful post. My Nissan Sunny manual doesn't mention anything about cool down period after a drive though it mentions to idle for 1 whole minute before driving with cold engine.

But I do idle the engine for 30 seconds to 1 minute after the drive.

[Omtoatom]

GTO, thank you for another very informative piece on turbos. There has been a spate of similarly educative articles on T-BHP lately on varied topics and that is a very satisfying occurrence. As I see it, the dividends of such information are not just limited to the forum but potentially also to the community at large. In a manner of speaking therefore, these things are invaluable. Very heartening to see our community doing its bit as well.

Although I have been religiously following almost everything you have recommended here, I still see a lot of folks who are completely unaware of these things. Almost blissfully ignorant!

It is surprising that an overwhelming majority of car owners don't even bother to read the instruction manual in full and hence miss out on such paramount stuff. And eventually when a failure happens, it is natural to just blame the manufacturer squarely for something that could so easily have been avoided. No one tends to look back on the best practices that could've been adhered to. Food for thought, isn't it?

[BMW-X5]

Hi GTO,

Thanks for a great article. I used to follow this rule until I sold off my Punto. Now I have got a SCORPIO VLX with the engine start stop feature, I hardly use it. I still try to follow the idling practice, but not everytime. I have seen the one minute idling stickers on earlier generation SCORPIOs but it is not there any more. Engine start stop switches off the engine after 10 seconds of idling.Is it because SCORPIO has got a water cooled turbo? Will the engine start stop feature damage the turbo in long run? I get tempted to use the engine start stop at least the cold mornings, as i dont mind A/C getting switched off for a couple of seconds. Also everytime service centre guys switch it on whenever I visit(had to 3 times in 5K kmts :( them.

[snaps]

Informative Thread for sure
Had I known so much in detail, I would have saved some bucks for sure. I had to change my Scorpio's turbobooster at around 70,000 KMs.
Now, I follow the ritual of 1 min idling before and after running the vehicle.

[Swanand Inamdar]

Quite an apt article, taking into consideration the amount of blown turbo's we read about nowadays.
Whether your car manual states it or not, I guess its better to be safe than sorry. Those turbos dont come cheap!

[mayankjha1806]

Wealth of information in this thread which i knew was important but never had the Time (errr patience) to do idling at start and stop. Although both my cars do not have turbo, but somewhere it was mentioned its recommended for non Turbo cars as well.

From now on the least i can do is drive slow at start and towards the end of the journey so as to have sufficient warm up and cool down in the process.

Thanks for this informative thread.

[bbhavan]

Excellent Thread. Very informative!!.

Thanks GTO for starting this new thread with so much vital informations.

I have seen that a driver , we hire for a long distance trip has started my new Innova, and revved the engine very hard, for 3,4 times for a minute.

Though I felt that it was not correct, I couldnt argue with him, considering the difference in the experience that we possess. What harm he had done on my new possession, god only knows.

Also as pointed out by S.S Traveller, I have the habit of using the car for very short travel only,say 1.5km a day, to my son's school in the morning. And only on Sundays, I am taking my car for a long trip.

Now I need to change the way, I use my car.


And about the Engine oil, what type of oil, Innova uses? Mineral or synthetic?

regards,

bbhavan.