Keeping the clutch in while stopped, puts wear on the thrust and throw out bearings unecessarily.

 

I mostly keep it active. If I can see that the light for cross traffic is turning yellow I'll keep my foot on the clutch or if it's a stop sign. If I do end up inching along in traffic I usually turn it off though.

 

No coolant circulating through the turbocharger if you are stopping the motor all the time. I worry more about that than the starter or the engine.

 

I wasn't aware we had all these mechanical engineers on the board.

 

+1 Surely the MINI/BMW engineers have considered that issue. Good grief...

 

I have to agree. If you don't think the engineers and management are up to snuff, why would you considering even buying a BMW or Mini? Surely you guys are torturing yourselves over design features that we must trust have been considered and accounted for. Otherwise, all our cars would be likely to fail under the 3 year boot-to-bonnet warranty and they'd be on the brink of bankruptcy. Lighten up and go for a drive with a big smile!

 

At least it's easy to turn off. In Arizona it won't operate much because we use AC a lot. It doesn't shut off the engine much when you use AC. I'm glad I don't have it. It's not one of the new features I'm interested in.

 

I'm interested in this feature because it means it'll have a beefier startup motor and battery and higher capacity alternator which should be more durable.

I probably won't be using it that much, but I do like to turn off my engine when waiting for a very long traffic/railroad light. The rule I found was anything more than 60 seconds, it's better to shut off the engine. But this is not accounting the starter motor or battery wear.

Even if I keep that function enabled, I wouldn't worry too much about wear and tear. I'm sure the engineers figured it out and it won't go kaboom right after the warranty expires.

 

You could be totally correct except for the fact that our cars are basically guinea pigs in many ways. This is what I know regarding turbochargers:

1.) The turbine side gets NUCLEAR-hot and depends on either engine oil or engine coolant (glycol) to cool the housing. If the engine is off, there is no coolant circulating through the housing, which means the turbine side (as well as bearings and lip seals) are just sitting there and cooking in their own heat. In fact, it's a common practice to install a device called a "turbo timer" in heavily modified applications, which keeps the engine idling for a number of minutes after you kill the ignition, specifically for the purpose of circulating coolant through the turbine housing, cooling the turbo down.

2.) Remember what you own and what it costs to replace what you own. Any manufacturer is going to spend and give you the minimal amount of product for the dollar since they are, well, a business. That's not to say that Mini is cheap or puts junk in their cars; I don't think they do. Borg Warner is one of the most reputable turbo mfrs. in the world.

But on the other hand, who pays the bill if the turbo needs replacing outside the warranty period? You? Or Mini? Point being, we don't know, and the question I then would ask is, "Is the possibility of replacing a turbocharger (or starter, for that matter) sooner rather than later worth whatever you feel like you are saving in gas by leaving auto-start enabled on this car?".

 

I assumed F56 comes with electric water pump, but I could be wrong. If yes, then there's no problem circulating the coolant during idle-stop. It won't circulate the oil though, so that may be a problem.

 

I don't know whether our turbos are oil or water cooled (Borg Warner manufactures both types) but even if the F56 has an electric water pump (and I don't believe it does; I assume it's driven off the accessory belt like most other vehicles...), there is nothing circulating when the engine is off.

Also, I have heard it mentioned that Mini may use a "beefed up" starter to handle the extra duty of the auto-start feature. That is all well and good except that there is no such thing as a beefed-up turbocharger. It's the same basic design they use for everything else.

 

Kind of like the CTV, steering pumps, timing chains?

 

I found in August in AZ that it was still start/stopping in early morning on the way to work and after the sun went down. Keeping the car parked in the garage or shade helped meant start/stop was more likely to work and the a/c didn't need to constantly work. 31.5/ 89 seems to be the cutoff i've found for start/stop working regularly.

Personally, I'd seen this feature in MINIs when I was living in the UK, and have been waiting yyyyyyeeeeeeaaaaaarsssss for it to come to the US. So I was thrilled my 2014 had it. :D

 

george, you are wildly speculating with your semi-knowledge about modern engines!

I can also wildly speculate that the engine has a little circulation pump for the turbo-cooling (my old saab 9-3 from -03 had it. When turning of the engine a liitle electric noise was heard for a minute in certain conditions).
I can also speculate that the engine will not shutdown if it needs cooling.

 

There is no oil being pumped through the turbocharger after you shut the ignition off on an F56. I just pulled up the schematic from Sewell and it is indeed an oil-cooled turbine, fed from one of the galleries of the cylinder head. So, the turbo is 100% dependent on the engine running in order to be cooled.

Again, I am not saying that this will be a problem. I have no idea. This car is totally new. Nobody really knows. However, what I am saying is that it is "regular duty" turbo housing that the owner could potentially put under "severe duty" if they leave the auto-start feature engaged. What I am also saying is that remember who will be paying for it if the turbo starts using a ton of oil outside the warranty period. A turbo should live forever, but.... It's your car: Drive it how you want.

 

Who's brave enough to put their F56 to a test? I'd like to know what happens after a solid five minutes of aggressive wot driving. If the car is smart enough, the auto start stop should not stop the engine immediately after driving this way. This would be done during the day and no climate control in use.

 

My 2007 MCS had a recall on the electric water pump that cools the turbocharger, it indeed runs when the car is turned off. It was the electical connection that was prone to causing a fire under the hood. I assume the F56 has one too.

 

BigNewt, the F56 turbo is oil-cooled. Fed from the cylinder head, drainback to oil pan. Only circulates when the engine is running. This is the "common" way most turbos are cooled by auto mfrs. Check out the schematic if you are curious.

 

All I know is that I received a recall letter from Mini stating that they would replace a pump that cools the turbocharger after the engine is shut off because in come cases the electrical connection to it would short out and cause a fire under the hood. I don't know what it pumps. If your contention is that the F56 turbo doesn't cool off if the engine is shut off then it makes no difference if it's shut off at a stoplight or in the driveway does it?

EDIT: Here's the link from the R56 forum sticky. It's definitely an auxiliary water pump that cools the turbo after engine is off. I would be surprised if the F56 doesn't have one too. One difference I notice between my 2007 Mini and this JCW is that some pump runs when I shut off the engine quite a bit more. I bet it's the turbo cooler because the JCW has a bigger turbocharger. http://www-odi.nhtsa.dot.gov/owners/...8&refurl=email

 

Again, that feature does not exist in the F56. It's "passive" rather than active turbo oiling. Apples and oranges.

Again, I don't know what, if any effect the extra duty cycle might have on turbo lifespan but on the other hand, neither does Mini. Or at least not in this case.

Just like the starter motor: It's the difference between using it say, 5X a day versus, say, 25X a day if the user elects to leave auto-start enabled. Except that the turbo is just sitting there and cooking in its own heat that many more times per day.

 

there were quite a lot turbo-fires in the 80-ies before proper turbo cooling was engineered

 

don't forget folks, the UK's had the start/stop technology for seven and a half years. yes, there are some big changes between the R56 and F56. but they've also had seven and a half years to sort out the big issues, and we're not hearing about major turbo meltdown from start/stop anywhere in the world that adopted this technology before it made the US minis.

 

I'm not sure why Mini would do away with the auxiliary water pump that cools the turbo for the F56. Doesn't make sense. They auto off feature has been on Euro Minis for years and I bet they have that cooling pump.

 

Like I've said several times, it may be a non-issue altogether. But you have it within your power to absolutely guarantee it will be a non-issue by simply de-selecting the auto-start feature.

BigNewt, just look at the schematic. There is no active cooling for the turbos on this car. Folks might not feel that it makes sense to do away with it but it's the truth. The diagram doesn't lie.

 

I've already done it a couple times. Engine stops. Auto start stop seems to be more dependent on outside air temperature than anything else.