[Turbo Head]

Originally Posted by GTO

Am also a hater of idling start-stop systems and have disabled it on my car .

With mass market cars, if manufacturers are given a choice of improving fuel efficiency by 10% & extending the turbochargers life from 125000 to 200000 km (as an example), I can guarantee you they will choose the former. Reason = that's what drives sales & helps them meet FE & emission targets. Hardly any 1st-owner owns his car for beyond 1.25 lakh km anyway, so what difference? No impact on warranty replacement costs either, because of this.

The OEMs spend hundreds of crores of rupees in FE-improvement efforts. Even a 0.2 kmpl difference is life & death for an engineer. A start-stop system is a no-brainer cheap way to increase the numbers, even if it comes at the cost of component life (including but not limited to turbos). I've driven 500 - 600 BHP cars with the stupid idling start-stop system.

Just like you I am a big hater of Start/Stop function, it can be extremely irritating and annoying, specially when one is driving in bumper to bumper traffic situation (which is quite common in Indian driving scenario).

Also I wonder how it's going to save fuel, specially when the car is started within seconds, it shuts down ?
I firmly believe it would rather result in wear and tear of lot of components involved, also affect the life of the battery adversely, which again is drawing loads of current, everytime the engine is cranked back to life.

I am really curious, how you managed to shut it down permanently ?
Can it be done in BMW X4 ?

[prajwalmr62]

This is what the user manual of Hyundai Venue states. I'm not sure what should be called as heavy load though.

[kptraveller]

Even Ford suggests not to stop the engine immediately after a hard drive and let the engine reach the idling speed so that turbo charger doesn't have a premature wear.

[Jeroen]

Originally Posted by kptraveller

Even Ford suggests not to stop the engine immediately after a hard drive and let the engine reach the idling speed so that turbo charger doesn't have a premature wear.

No, that is not what it says: it says not to switch of the engine whilst running at high speed. And to only shut the engine down once it has reached idle speed.

The first you should not do with any engine, nowhere does it say to idle for a minute. When you park your engine and come of the throttle the engine is idling right away and according to this Ford instruction you can turn the engine off. It says wait till idle, not idle for a minute.

Jeroen

[Lowflyer23]

I think even though the auto start/stop feature might have some negative impacts on the turbocharger, they'll be very minute and would take years and Lacs of kilometres for the turbo to give up finally. Not saying that premature turbo failure doesn't occur, but it's quite rare and I have seen Innova taxis with 2 lac plus Kms under the belt running just fine and the drivers immediately switch off the engine after a long highway run.

A very high running is not the requirement of most private owners hence there is lesser chance of people having to experience a damaged turbocharger.

[kptraveller]

Originally Posted by Jeroen

No, that is not what it says: it says not to switch of the engine whilst running at high speed. And to only shut the engine down once it has reached idle speed.

The first you should not do with any engine, nowhere does it say to idle for a minute. When you park your engine and come of the throttle the engine is idling right away and according to this Ford instruction you can turn the engine off. It says wait till idle, not idle for a minute.

Jeroen

Hi Jeroen,

While I don't have experience of driving other brand vehicles, but what I have seen is my Figo diesel engine doesn't come to the idle speed as soon as you park the car. I have seen that engine still runs at above normal idle rpms for a minute after a long high drive. But again, it would vary depending on one's driving style.

Regards,
Ravi

[Motard_Blr]

Here is my understanding of why idling before stopping the engine was a requirement for older turbo engines:

Most older turbos have hydrodynamic (sleeve) bearings. Those operate only when there is a film of oil between the bearing surfaces. If the bearing is running and there is a loss of oil pressure, the oil film rapidly breaks down and the bearing could be damaged by friction.

Newer engines, particularly with the latest variable geometry nozzle turbos, are equipped with high tech ball bearing turbos. These are much less sensitive to oil pressure (not insensitive). So they are less likely to be damaged by careless engine usage. Unfortunately, I am unable to figure out which cars have which type of turbocharger. If someone else could help with this, I would be grateful.

However, another purpose of idling for a minute before stopping the engine is to cool the turbo. Oil flow and, air or exhaust flow will prevent heat soaking of the turbo. I think this the more important purpose of idling for a minute before stopping the engine.

The idle stop system will only stop the engine when it is already idling, so, in theory, it should cause any problems to the engine.

[shancz]

Originally Posted by condor

This has been discussed earlier in the micro-hybrid thread. IMO, not enough to offset the cost of such a system. Will be best in an EV.

Thanks, went through the other micro-hybrid threads like you mentioned.
Felt like Deja vu (including members) and quite exhaustive information
Including here for reference :

• Why you must practice the "Idling Rule" with Turbo-Charged Cars : GTO (Why you must practice the "Idling Rule" with Turbo-Charged Cars)
• Explained! How Maruti's SHVS System Works : Leoshashi (Explained! How Maruti's SHVS System Works)
• Maruti Ciaz SHVS with Integrated Starter Generator & idling start / stop system : RavenAvi (Maruti Ciaz SHVS with Integrated Starter Generator & idling start / stop system. EDIT: Now launched!)

Originally Posted by saikarthik

Bigger the displacement, the benefit is more. Typically for 2 to 3.2L engines one can get ~4-5% depending on the duration and frequency of stop.

I have worked on Scorpio start stop system and the reason of default ON is to satisfy the requirements laid by the CAFE regulations. Manufacturer can get extra points for keeping the idle start stop function on default ON on every ignition cycle.

Thanks, also as mentioned by deetjohn in this post (Maruti Ciaz SHVS with Integrated Starter Generator & idling start / stop system. EDIT: Now launched!) tax subsidies as well.

Originally Posted by Jeroen

As mentioned by other members it varies. Obviously, cruising on the motorway it does nothing. But it does come into its own in city driving. It depends a bit on whom you would like to believe, but most sources indicate anywhere between 4-12% during city driving.

Thanks, I see the use in city traffic.
Slightly OT but I also went through the posts on engine wear during cold starts and idling vs driving out. Personally it was counter intuitive since I followed the idling 30 seconds SOP which was also mentioned in the Matiz's manual but the WagonR's(K10B) manual explicitly warns against idling a cold engine and recommends to "warm up by driving" while the XUV300's manual explains the reasons to avoid prolonged idling of a cold engine.
So RTM is the way to go.


I do agree with others that idling for 30 seconds won't hurt and that it will be a personal preference in the end.
But my most important takeaway is that either way nothing immediate/catastrophic is going to happen even if the ESS is being used, like Jeroen said since quite a few drivers don't even know if they're driving a turbo.

Good learnings though

[vj_torqueaddict]

Thanks for this thread. I was contemplating to start this topic too after purchasing Bolero.

I find the start/stop feature to be annoying , which I have mentioned in the Bolero BS6 thread as well. Not to mention scary at times if one forgets to switch it off.

I use my vehicle mainly for the highways, with rpm constantly hovering around 2000rpm for long duration , I am pretty sure it is in the meat of the turbo zone. Start/stop waits for 5 seconds and switches it off, not sure if 5 seconds is enough.

Wonderful insights on this thread nonetheless.

[landcruiser123]

As tsk1979 says, we’re looking at planned obsolescence. Why do auto-makers suggest life-long ATF? Because the transmission will fail long after the warranty period and they can sell you another car.

My friendly mechanic had this to say: Do you pour hot water in a cold bowl? Probably no, because of the thermal shock which can cause glass to shatter. Agree that metal is different from glass, but short trips and hard driving followed by no idle means turbos wear out prematurely. I do agree that it is probably not something most Indians will be worried about as many cars don’t tough 1.25 lakh km with the first owner.

Turbochargers ram significantly more air into the engine. Compression always generates tremendous heat. A 30-60 second idle will gradually cool the system and let air last longer. And I’d suggest turning off the auto-start-stop system.

[venkyhere]

a very "idling for dummies" way of looking at the question :

1. if your turbo car has start/stop - highly likely that the logic to determine when to do the engine off thing has been given some thought. The first thing to consider by the systems engineer would be battery. The second thing to consider would be the turbo. So, we must place trust in the engg dept of the company who is selling you the car.

2. If your turbo car doesn't have start/stop - what are you going to lose by idling for 1 min on a cold start morning or idling for 1 min after a pedal to metal highway run ? Almost nothing. So don't fret over the theory or science behind it - simply idle. The turbo is too expensive and sensitive an item to 'take a chance, since I have the knowledge' betting. People who have no idea about such things (who dont even know what a turbo is and whether their car has one) - let them continue doing what they do, rightly or unnecessarily - you have nothing to lose by spending 1 min extra at the start and stop - probably your turbo will last 2 lac kms instead of 1 lac kms, before starting to show signs of trouble. The price to pay for turbo idling is a pittance. So do it.

[railfanwithk750]

Originally Posted by venkyhere

If your turbo car has start/stop - highly likely that the logic to determine when to do the engine off thing has been given some thought. The first thing to consider by the systems engineer would be battery. The second thing to consider would be the turbo. So, we must place trust in the engg dept of the company who is selling you the car.

This is the exact point that bothered me in the first place. My concern is not about should we idle our turbo engines or not. Rather, I want to be sure on whether we should we blindly let the car "do it's thing", trusting the manufacturers to have done their research thoroughly? Do we have any evidence that the if the engine switches itself off due to an embedded algorithm, it is not going to harm the engine, not just within the warranty period but beyond that period as well? What's the assurance that it is not a ploy by manufacturers to make profit by replacing parts at exorbitant cost, at the same time, absolving themselves of any responsibility for damage inflicted by their own systems after the 2-year (or the 5 year extended warranty) period has passed?

I really pray cars do not head the 'disposable' route that phones have taken. Feature phones of the 2005 era used to last a decade. I still own a phone that cost me ₹7000 when purchased in 2005, in perfect working condition. These days, I'd be lucky if my 2020 'midrange' smartphone worth ₹35000 lasts beyond 2022.

[ghostrider]

I actually tried an experiment where I kept the start/stop system on for a full tank of gas (city driving only), and found it made literally a +0.3kpl difference to the average economy when I filled up again, so I guess that lines up with the claimed of 4-5%.

In fact, I think the 12% claim's ludicrous - I'd love to see real-world evidence of start/stop providing such a massive bump in fuel economy.

The fact that the difference to the economy is so negligible, coupled with the fact that it's annoying as hell meant that the start/stop was the first thing I coded out on my F30 (which took me all of thirty seconds).




Thank god for Bimmercode.

Start stop is getting much, much better than it was.
In the new Merc CLS53 for example, the EQ Boost system (Merc's name for 48-volt mild hybrid tech) makes the start/stop so seamless you literally can't tell that it's happening.


Of course, all of this becomes completely redundant when we're all driving EVs in a few years.

Originally Posted by Turbo Head

I am really curious, how you managed to shut it down permanently ?
Can it be done in BMW X4 ?

Extremely easy with the aforementioned Bimmercode app and an OBD2 adapter, takes all of thirty seconds. If you lived in Bombay I could've done it for you.

[IP_Man]

Originally Posted by Jeroen

If you want to know what is good for your engine/turbo; first and foremost consult your owner's manual. If it is not mentioned, it is simply not required. Feel free to idle, but other than polluting the air a bit longer it is not going to make any difference.

That's fair enough but is there any statistical study of turbo life span for ESS and non ESS vehicles?

Waiting thirty seconds (in idling) practically do not hurt for the longevity of the turbo in non ESS vehicles.

For ESS vehicles, trick is not to take jack rabbit start after engine starts. Most diesel vehicle can crawl at idling. Allow engine oil to reach to turbo before accelerating car. Because turbo spins at very high RPM and needs good lubrication to reduce wear and tear.

Unfortunately, delayed engine stop after vehicle comes to standstill is not possible in ESS system. This is necessary to avoid oil coking due to very temperature of the turbo.

[Jeroen]

Originally Posted by IP_Man

Thats fair enough but is there any statistical study of turbo life span for ESS and non ESS vehicles?
.

I refer to my earlier post: This is only a concern for people who frequent car forum. The rest of the world, say 99% of car owners would not even know what you are talking about, nor care. In fact, many car owners would not even know if they were driving a car with or without a turbo engine, nor could they care.

We have a thread somewhere on the forum, which also shows, that at least our members, who one would think, are car enthusiast, rarely if ever read the owner manual. If I extrapolated into world reality it probably means that most car owners might not even be aware they have a car owner manual.

Does all this complete indifference and ignorance lead to unusually high engine and turbo wear and tear amongst all of these hundreds of millions car owners? Are the streets littered with cars stranded due to problems relating to this very topic? I don’t think so.

Car lease companies have a huge amount of data on just about any car under the sun and they are not aware of any problems due to most of their customers not having a clue. And trust me, many company lease car lead a harsh life!

Just about all modern cars and engines, as long as normal maintenance is done properly, will do easily 150.000 km without any major repairs required due to wear and tear of anything related solely to ESS. Cars these days tend to be scrapped long before they are technically worn.


Jeroen