Subaru Outback engine stop/start

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JAZZISCOOL
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Re: Subaru Outback engine stop/start

Post by JAZZISCOOL » Thu Jan 23, 2020 8:54 pm

jpohio wrote:
Thu Jan 23, 2020 8:45 am
I test drove a 2020 Subaru Outback yesterday and was very impressed with the looks, ride, quality, and features/functions. When I stopped at a stop sign, the engine apparently shut off, and when I pressed the gas pedal the engine started up again.......

For those with Subaru's - have you found a way to turn off this feature permanently, do you just live with it, or do you shut it off prior to every trip?

Thanks
I also just drove a 2020 Outback recently (have an older Outback currently so am researching a newer vehicle.) I didn't experience the stop/start feature but did discuss it briefly with the salesman.

IMO, I like the idea of the stop/start function for emissions/environmental reasons and is something I could probably get used to.

I am more concerned about the CVT transmission based on some of the early research I have done on the Outbacks and some other cars. The Subaru salesman stated that they haven't had any CVT issues since after the 2015 model year but I don't know if that is true or not (not a car geek.) He said the warranty on the 2020 Outback transmission is 6 years, I believe.

My friend's son works at a transmission shop and said they get a lot of cars in with CVT problems so not sure how I get more comfort with this issue. :?

Some CVT posts found here:

https://www.carcomplaints.com/Subaru/Ou ... rivetrain/

viewtopic.php?t=298863

smalliebigs
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Re: Subaru Outback engine stop/start

Post by smalliebigs » Thu Jan 23, 2020 10:27 pm

Teague wrote:
Thu Jan 23, 2020 8:01 pm
I've wondered about this. Suppose the system is stopped for a light, and the clueless driver floors it the second the light turns green. Let's have them towing a good sized trailer, uphill, for good measure. So we've got all this load on the rod bearings and other parts squeezing out that oil film all of a sudden, before we've reestablished full oil pressure and flow, no? That sounds pretty dicey to me. What am I missing?
There are many factors that need to be met for the start/stop system to activate, such as: battery voltage, engine temperature, oil pressure, gear, steering wheel angle, etc., etc. So the conditions will naturally eliminate if the engine is cold and if the oil pressure is low.

What you need to realize is that modern cars, since 10 years ago, are drive by wire. You're not physically activating the throttle, but actually making a torque request to the ECU. Based on how deep you push the throttle, and if there's towing, the ECU will control the RPM, fuel, gearing, etc., to provide the best torque as required, whilst maintaining system safety. So it is near impossible to cause anything hairy. We design the engine and control systems to be conservative so as to stay within the safety margins. The last thing that we definitely want is to pay out warranty claims.

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Re: Subaru Outback engine stop/start

Post by mmmodem » Fri Jan 24, 2020 6:03 am

TheGreyingDuke wrote:
Thu Jan 23, 2020 7:22 pm
As a lifelong manual transmission person, I am contemplating purchasing what may be the last such vehicle, I assume that this technology is NOT available on a stick?
Of course it is. I rented a manual vehicle in France with Start/Stop. The engine turns off at low speeds with your for off the clutch. It springs back to life if you press on the clutch or to power cycle the AC. I do not know if such a system exists in the US.

onourway
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Re: Subaru Outback engine stop/start

Post by onourway » Fri Jan 24, 2020 6:19 am

If this feature is noticeable enough that you are complaining about it - it’s the fault of the manufacturer who has implemented it poorly. Drive a Toyota Prius of any age and this feature will hardly be noticeable, even if you are paying attention. And it happens far more frequently in a hybrid like that, and I don’t think I’ve ever heard of anybody complain of starter problems on a Prius or any other issues regarding from excessive wear and tear because of it.

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Re: Subaru Outback engine stop/start

Post by bubbadog » Fri Jan 24, 2020 7:29 am

batpot wrote:
Thu Jan 23, 2020 3:40 pm
why are people so adverse to this feature?
Just because "it's different"?
I'm so confused why this is such a big turn off.
My understanding is that this feature on Subarus is not as smooth as on other brands.

I believe it has to do with Subarus having boxer engines.

I have read several online reviews and a lot of them have commented about how rough the restart of the engine is compared with other brands.

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Re: Subaru Outback engine stop/start

Post by Pigeon » Fri Jan 24, 2020 8:02 am

I have it in my 2019 Forester. It's a simple press of a button to turn it off, and I usually do. If you forget to do it when you start the car, you can still hit the button at any time to disable it. The amount of gasoline it saves in incredibly tiny, and it's quite jarring when the car starts back up again. I was concerned about it when car shopping, but it's a non-issue on my car (and I love the car). If it were a menu item, I would be more irritated.

I understand that the starter is more robust to accommodate this, but I would expect that at some point in the life of the car, the starter would fail. I keep my cars for a long time. In a car without this feature, that will happen in my driveway or in a parking lot. It won't happen when I'm in a busy intersection during the middle of rush hour traffic, which seems more likely with the new feature.

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Re: Subaru Outback engine stop/start

Post by lazydavid » Fri Jan 24, 2020 11:22 am

onourway wrote:
Fri Jan 24, 2020 6:19 am
If this feature is noticeable enough that you are complaining about it - it’s the fault of the manufacturer who has implemented it poorly. Drive a Toyota Prius of any age and this feature will hardly be noticeable, even if you are paying attention. And it happens far more frequently in a hybrid like that, and I don’t think I’ve ever heard of anybody complain of starter problems on a Prius or any other issues regarding from excessive wear and tear because of it.
Comparing a hybrid to a pure-ICE car and saying the manufacturer didn't implement it properly is kind of unfair. In a Prius, the SMG is used to both get the car moving and start the engine, sometimes at the same time, sometimes not. This is not the same thing as in an ICE car, where a conventional starter must fire the motor and CANNOT move the vehicle on its own. Additionally, hybrid engines use the Atkinson cycle, where the intake valves remain open for a good portion of the compression stroke. This is good for starting smoothness, but horrible for low-speed power, which is why you almost never see Atkinson-powered conventional cars.

Teague
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Re: Subaru Outback engine stop/start

Post by Teague » Fri Jan 24, 2020 11:38 am

smalliebigs wrote:
Thu Jan 23, 2020 10:27 pm
Teague wrote:
Thu Jan 23, 2020 8:01 pm
I've wondered about this. Suppose the system is stopped for a light, and the clueless driver floors it the second the light turns green. Let's have them towing a good sized trailer, uphill, for good measure. So we've got all this load on the rod bearings and other parts squeezing out that oil film all of a sudden, before we've reestablished full oil pressure and flow, no? That sounds pretty dicey to me. What am I missing?
There are many factors that need to be met for the start/stop system to activate, such as: battery voltage, engine temperature, oil pressure, gear, steering wheel angle, etc., etc. So the conditions will naturally eliminate if the engine is cold and if the oil pressure is low.

What you need to realize is that modern cars, since 10 years ago, are drive by wire. You're not physically activating the throttle, but actually making a torque request to the ECU. Based on how deep you push the throttle, and if there's towing, the ECU will control the RPM, fuel, gearing, etc., to provide the best torque as required, whilst maintaining system safety. So it is near impossible to cause anything hairy. We design the engine and control systems to be conservative so as to stay within the safety margins. The last thing that we definitely want is to pay out warranty claims.
Makes sense. Thanks.
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OAG
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Re: Subaru Outback engine stop/start

Post by OAG » Fri Jan 24, 2020 12:09 pm

I have that "feature" on my VW Tiguan. On this vehicle the engine shuts off when you stop (using your brakes) and it will restart when you move you foot off of the brakes. It, of course can be turned off, and reengages when you restart the vehicle. I initially disliked it and turned off all the time. However, now I just ignore the thing. Seems like it does not bother me any longer and the vehicle is under warranty for 6 years so I am not worried about the starter or any other mechanical problems involving the "feature".
Last edited by OAG on Fri Jan 24, 2020 1:39 pm, edited 1 time in total.
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dbr
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Re: Subaru Outback engine stop/start

Post by dbr » Fri Jan 24, 2020 12:11 pm

I had this in a rented Volvo. It was just really irritating. We figured out how to turn it off for the duration.

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Re: Subaru Outback engine stop/start

Post by ncbill » Fri Jan 24, 2020 5:12 pm

RootSki wrote:
Thu Jan 23, 2020 8:36 pm
TheGreyingDuke wrote:
Thu Jan 23, 2020 7:22 pm
As a lifelong manual transmission person, I am contemplating purchasing what may be the last such vehicle, I assume that this technology is NOT available on a stick?
Manual transmissions are irrelevant in the era of 8 and 10 speed dct’s. They are fun and you do feel connected to the power train, for a daily driver, I’ll take more gears over a stick any day.
Manual trannys are a heck of a lot cheaper to fix than 8-10 speed automatic transmissions...

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RootSki
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Re: Subaru Outback engine stop/start

Post by RootSki » Fri Jan 24, 2020 5:19 pm

ncbill wrote:
Fri Jan 24, 2020 5:12 pm
RootSki wrote:
Thu Jan 23, 2020 8:36 pm
TheGreyingDuke wrote:
Thu Jan 23, 2020 7:22 pm
As a lifelong manual transmission person, I am contemplating purchasing what may be the last such vehicle, I assume that this technology is NOT available on a stick?
Manual transmissions are irrelevant in the era of 8 and 10 speed dct’s. They are fun and you do feel connected to the power train, for a daily driver, I’ll take more gears over a stick any day.
Manual trannys are a heck of a lot cheaper to fix than 8-10 speed automatic transmissions...
Not if you’re under warranty.

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Re: Subaru Outback engine stop/start

Post by ncbill » Fri Jan 24, 2020 5:25 pm

RootSki wrote:
Fri Jan 24, 2020 5:19 pm
ncbill wrote:
Fri Jan 24, 2020 5:12 pm
RootSki wrote:
Thu Jan 23, 2020 8:36 pm
TheGreyingDuke wrote:
Thu Jan 23, 2020 7:22 pm
As a lifelong manual transmission person, I am contemplating purchasing what may be the last such vehicle, I assume that this technology is NOT available on a stick?
Manual transmissions are irrelevant in the era of 8 and 10 speed dct’s. They are fun and you do feel connected to the power train, for a daily driver, I’ll take more gears over a stick any day.
Manual trannys are a heck of a lot cheaper to fix than 8-10 speed automatic transmissions...
Not if you’re under warranty.
But out of warranty those particular auto trannies can cost as much as an engine...

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Re: Subaru Outback engine stop/start

Post by bloom2708 » Fri Jan 24, 2020 5:27 pm

The people that really hate the stop/start are the "jackrabbit starters" from being stopped.

If you mash the peddle down to get to 30 or 35 or 40 mph as fast as you can in town, the stop/start is "annoying". Why is the car jerking? Well..let me explain...

My father-in-law is a jackrabbit starter. He was so annoyed with the stop/start. I tried to explain....

I drive and am calm. The stop/start is seamless if you let it do its thing. A calm driving style tends to get you "in trouble" with the jackrabbit zoomers behind you. (PS. I am 48, not 78 but my wife thinks I drive like I'm in my 70s or 80s. I think that is a compliment. I still get there on time).

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smalliebigs
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Re: Subaru Outback engine stop/start

Post by smalliebigs » Fri Jan 24, 2020 5:40 pm

Regarding the comments on manual transmission and cost to repair the 8-speeds. The sales information that all OEMs have now indicate that most buyers of new cars lease, rather than buy. Thus, for most buyers, it won't be their problem with regards to repair. This is the advantage of leasing that the market is just leaning on, in addition to the lower monthly costs. Whether or not you agree is another matter. Add to the fact that if you want a new car, 95+% of new cars sold are automatic transmissions. So that is the norm now.

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vitaflo
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Re: Subaru Outback engine stop/start

Post by vitaflo » Fri Jan 24, 2020 5:50 pm

I have an OBD2 dongle that allows me to permanently disable stop/start on my VW GTI by modifying the settings of my ECU. Most cars have situations where stop/start will auto shut off. For example if the temp outside is under some threshold (so you can continue to heat the car) or if the car thinks the battery doesn't have enough voltage to restart the car when it turns off, the start/stop will be disabled on its own.

Changing the ECU settings will basically keep these settings in play all the time and make it so the car always disables start/stop. The one I use on my GTI is the voltage setting. Normally stop/start is turned off if the battery voltage drops below 7.6v. I just tell it to disable start/stop if the voltage instead drops below 12.1v. Since it's a 12v battery it will always be below that value and thus the car is fooled into turning off stop/start on its own.

Whether you can do this on a Subaru I don't know, but it's the type of thing to look into.

smalliebigs
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Re: Subaru Outback engine stop/start

Post by smalliebigs » Fri Jan 24, 2020 5:56 pm

Of course, doing the above is at your own risk and may potentially void warranty (if you have any).

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Re: Subaru Outback engine stop/start

Post by Picksburgh » Fri Jan 24, 2020 6:08 pm

AerialWombat wrote:
Thu Jan 23, 2020 12:18 pm
I currently have a 2016 Outback, and have been drooling about the new 2020's because of the increased towing capacity. However, having not yet driven one, I did not know about this new "feature". This might be a deal breaker for me. Thanks for the heads up.
The auto start stop turns off automatically when you are towing. At least that’s what the sales guy told us. Haven’t tried it yet with our 2020 Forester. It also is disabled when it’s to hot or to cold out, or you stop on a hill. Living in Pittsburgh we have rarely even notice it.

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Re: Subaru Outback engine stop/start

Post by Atilla » Fri Jan 24, 2020 6:30 pm

It's annoying you can't permanently turn off the auto stop/start feature - but if it's a matter of pushing an extra button every time you drive - meh - you get used to it.

My wife's stupid Lexus defaults to ECO mode every time you start the thing. You have to switch to SPORT mode every time you start rather than having it stay where you wanted it.

My Infiniti sedan, I have to press a button after every start to deactivate the traction control I don't want cramping my acceleration by seriously bogging the engine if the rear wheels spin just a little bit. I prefer the setting stay where I WANT IT.

I feel your pain but it is what it is.
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Re: Subaru Outback engine stop/start

Post by AerialWombat » Fri Jan 24, 2020 8:49 pm

Picksburgh wrote:
Fri Jan 24, 2020 6:08 pm
AerialWombat wrote:
Thu Jan 23, 2020 12:18 pm
I currently have a 2016 Outback, and have been drooling about the new 2020's because of the increased towing capacity. However, having not yet driven one, I did not know about this new "feature". This might be a deal breaker for me. Thanks for the heads up.
The auto start stop turns off automatically when you are towing. At least that’s what the sales guy told us. Haven’t tried it yet with our 2020 Forester. It also is disabled when it’s to hot or to cold out, or you stop on a hill. Living in Pittsburgh we have rarely even notice it.
Ahh, that definitely helps. Thanks for the info, I appreciate it!

westie
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Re: Subaru Outback engine stop/start

Post by westie » Fri Jan 24, 2020 10:17 pm

I could live with that annoyance, but then again my Subaru Forester, 2014, which I bought new, has had the head unit replaced, (replacement worked for 3 months) the A/C replaced, the CVT replaced, the wheel bearings replaced and it only has 55,000 miles on it. First vehicle I've ever owned in 40 years that needed more than routine maintenance. Still have it, but never again.

tim1999
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Re: Subaru Outback engine stop/start

Post by tim1999 » Fri Jan 24, 2020 10:56 pm

My mom's Cadillac would normally make you hit the disable button again every time you start the car if you don't want auto start/stop on. She paid to get some device rigged up that tricks the car's sensors into thinking the hood is open when it's not, which apparently keeps auto start/stop deactivated permanently, so she no longer has to press the button each time. :shock:

Personally, I hate the feature and won't buy a car unless auto stop/start can at least be disabled each time the car is started.

IMO
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Re: Subaru Outback engine stop/start

Post by IMO » Sat Jan 25, 2020 1:26 am

smalliebigs wrote:
Thu Jan 23, 2020 2:32 pm
I am an engineer working in the automotive industry. I am on the engine combustion side, not on electrical. However, I think I can give some context regarding the engine stop/start.

By federal regulations, this stop/start functionality cannot be permanently turned off.

With regards to the wear, the systems are designed to be robust enough to tolerate a long term usage with stop/starts. It might not seem like much, but the stop/start system is design to help us tackle the emissions and CO2 output during federal drive cycle tests. Every bit helps.
The reason that a start/stop system was introduced is pretty obvious.

What I'm having trouble understanding is "designed to be robust enough". 1st thing that went through my mind when I 1st say the system in action is "I wonder how long that starter will last and how much is will cost to have it replaced?" NOTHING is inexpensive when it comes to having one's car worked on, and how many start/stop/start/stop cycles does a car go though say for the 1st 100,000 miles? I have my personal doubts about longevity of the new starters, is there data on this feature?

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Re: Subaru Outback engine stop/start

Post by Swansea » Sat Jan 25, 2020 6:30 am

You may want to check and see if the dealer has the ability and/or willingness to disable the function. BMW dealers can.

"The start/stop feature in the current BMW 3 Series is, by default, activated every time you get in and start the car. If you don't like it, you can deactivate the feature by pressing a button on the dash; however, the next time you turn the car off and start it again (with the key), the start/stop system will kick in.

This is too much hassle for some drivers, who wish start/stop to remain off unless they decide otherwise. To accommodate them, BMW has given dealers permission to activate the system's Last User Mode, which will start the car with stop/start in the same mode as when the car was shut down. Of note, BMW M models come with Last User Mode enabled automatically. There's a service bulletin below with the particulars."

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Re: Subaru Outback engine stop/start

Post by TheGreyingDuke » Sat Jan 25, 2020 7:23 am

smalliebigs wrote:
Fri Jan 24, 2020 5:40 pm
Regarding the comments on manual transmission and cost to repair the 8-speeds. The sales information that all OEMs have now indicate that most buyers of new cars lease, rather than buy. Thus, for most buyers, it won't be their problem with regards to repair. This is the advantage of leasing that the market is just leaning on, in addition to the lower monthly costs. Whether or not you agree is another matter. Add to the fact that if you want a new car, 95+% of new cars sold are automatic transmissions. So that is the norm now.
Correct, but many posts here tout the benefit of a used car purchase so the risk goes to someone.

In any event, I do not tout sticks for their cost-benefit (which in any event have been reduced by the better fuel economy of many of the fancy automatics). I prefer the connection to the act of driving, keeping my foot off the brake at stoplights and the fact that many young people don't ask to borrow my car!
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Joe3zz
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Re: Subaru Outback engine stop/start

Post by Joe3zz » Sat Jan 25, 2020 9:28 am

I like the start/stop feature on my Ford F-150. I would think it would appeal to Bogleheads-more $ in your pocket.

When towing a trailer, the truck is in Tow/Haul mode and it automatically turns the start/stop off. So at least in Fords, not a factor when towing.

Also, there is a little time for oil to start flowing, as the engine turns on when you start releasing the brake, not when you hit the gas.
Teague wrote:
Thu Jan 23, 2020 8:01 pm
smalliebigs wrote:
Thu Jan 23, 2020 5:46 pm
There is absolutely no extra wear and tear at all, other than needing a stronger starter motor and larger battery
I've wondered about this. Suppose the system is stopped for a light, and the clueless driver floors it the second the light turns green. Let's have them towing a good sized trailer, uphill, for good measure. So we've got all this load on the rod bearings and other parts squeezing out that oil film all of a sudden, before we've reestablished full oil pressure and flow, no? That sounds pretty dicey to me. What am I missing?

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Re: Subaru Outback engine stop/start

Post by Nowizard » Sat Jan 25, 2020 9:40 am

After reading this thread, I tried using Sport mode and it does disable the stop/start mechanism, though it also reverts to the standard position when the engine is turned off after driving. Sport gives somewhat more power and somewhat less gas mileage. Both approaches of sport and pressing the dash button require pressing a button. I prefer to directly disable the start/stop with its button. This is a 2019 Forester and it seems like the 2020's may be different.

Tim

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Re: Subaru Outback engine stop/start

Post by RootSki » Sat Jan 25, 2020 9:48 am

A friend of mine bought a 2019 Forrester last year. I asked her if I could try the start/stop system by driving around my neighborhood for a bit and then I let her drive my Volvo.

Subaru's system is a little jarring at first. Volvo's must have much more dampening on the engine mounts and starter because you don't really feel the engine turn over. Maybe it's the Boxster engine design as others have suggested. On the Forrester, there's a bit of a shutter and it's not a smooth.I imagine the Outback is similar to the Forrester.

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Re: Subaru Outback engine stop/start

Post by robphoto » Sat Jan 25, 2020 9:55 am

We've driven our Prius V 190,000 with no problem with the starter, etc. from the engine shutoff.

I think it's one of those things that seem weird at first, then you forget about it.

Our recent rental cars have also had this feature: Ford Escape, Chevy Equinox, and others.

In Boston, standing on a main street a bunch of taxis, mostly Camry Hybrids, pulled up to a stoplight, and the engines all stopped.

So for that time, they were all quiet and not burning gas-- there's certainly some benefit to that!
Last edited by robphoto on Sat Jan 25, 2020 10:01 am, edited 1 time in total.

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Re: Subaru Outback engine stop/start

Post by dbr » Sat Jan 25, 2020 9:58 am

robphoto wrote:
Sat Jan 25, 2020 9:55 am
We've driven our Prius V 190,000 with no problem with the starter, etc. from the engine shutoff.

I think it's one of those things that seem weird at first, then you forget about it.

Our recent rental cars have also had this feature: Ford Escape, Chevy Equinox, and others.
My only experience was with a rented Volvo. At first it seemed unobtrusive. It took a little while to understand what was happening. Over time, having the car for two weeks, it got more and more irritating, like a water torture, until I finally figured out how to turn it off.

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Re: Subaru Outback engine stop/start

Post by mpnret » Sat Jan 25, 2020 12:47 pm

Mazda has one of the better stop/start systems that is faster and doesn't use the starter. From their website: "While conventional idling stop systems rely on a starter motor to restart the engine, Mazda's i-stop restarts the engine through combustion; fuel is directly injected into a cylinder while the engine is stopped and ignited to generate downward piston force. The result is a quick and quiet engine re-start compared to other systems and a significant saving in fuel.

To restart the engine by combustion, the compression-stroke and expansion-stroke pistons need to be stopped at exactly the correct positions to create the right balance of air volumes. Mazda's i-stop ensures precise control over the piston positions during engine shutdown. With all the pistons stopped at the optimum positions, the system then identifies the initial cylinder for fuel injection. It injects fuel and ignites it to restart the engine. Even at extremely low rpm, cylinders are identified for sequential ignition, making the engine quickly pick up to idling speed.

These technologies enable the system to restart the engine with exactly the same timing every time, to enhance fuel economy, and to deliver smooth and comfortable acceleration for the driver at restart. The restart takes place in a mere 0.35 seconds (internal measurement on vehicle with automatic transmission), which is about half of the time taken by conventional starter-motor idling stop systems."

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Re: Subaru Outback engine stop/start

Post by Sconie » Sat Jan 25, 2020 12:52 pm

jpohio wrote:
Thu Jan 23, 2020 8:45 am
This seems like it could get very annoying very quickly.
Exactly why I didn't buy one!
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Re: Subaru Outback engine stop/start

Post by JAZZISCOOL » Sat Jan 25, 2020 1:04 pm

mpnret wrote:
Sat Jan 25, 2020 12:47 pm
Mazda has one of the better stop/start systems that is faster and doesn't use the starter. From their website: "While conventional idling stop systems rely on a starter motor to restart the engine, Mazda's i-stop restarts the engine through combustion; fuel is directly injected into a cylinder while the engine is stopped and ignited to generate downward piston force. The result is a quick and quiet engine re-start compared to other systems and a significant saving in fuel.

To restart the engine by combustion, the compression-stroke and expansion-stroke pistons need to be stopped at exactly the correct positions to create the right balance of air volumes. Mazda's i-stop ensures precise control over the piston positions during engine shutdown. With all the pistons stopped at the optimum positions, the system then identifies the initial cylinder for fuel injection. It injects fuel and ignites it to restart the engine. Even at extremely low rpm, cylinders are identified for sequential ignition, making the engine quickly pick up to idling speed.

These technologies enable the system to restart the engine with exactly the same timing every time, to enhance fuel economy, and to deliver smooth and comfortable acceleration for the driver at restart. The restart takes place in a mere 0.35 seconds (internal measurement on vehicle with automatic transmission), which is about half of the time taken by conventional starter-motor idling stop systems."
Interesting. I recently took a test drive in a Mazda CX-5 and they didn't mention this. Maybe on other models (?).

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Re: Subaru Outback engine stop/start

Post by Gort » Sat Jan 25, 2020 1:20 pm

mpnret wrote:
Sat Jan 25, 2020 12:47 pm
Mazda has one of the better stop/start systems that is faster and doesn't use the starter. From their website: "While conventional idling stop systems rely on a starter motor to restart the engine, Mazda's i-stop restarts the engine through combustion; fuel is directly injected into a cylinder while the engine is stopped and ignited to generate downward piston force. The result is a quick and quiet engine re-start compared to other systems and a significant saving in fuel.

To restart the engine by combustion, the compression-stroke and expansion-stroke pistons need to be stopped at exactly the correct positions to create the right balance of air volumes. Mazda's i-stop ensures precise control over the piston positions during engine shutdown. With all the pistons stopped at the optimum positions, the system then identifies the initial cylinder for fuel injection. It injects fuel and ignites it to restart the engine. Even at extremely low rpm, cylinders are identified for sequential ignition, making the engine quickly pick up to idling speed.

These technologies enable the system to restart the engine with exactly the same timing every time, to enhance fuel economy, and to deliver smooth and comfortable acceleration for the driver at restart. The restart takes place in a mere 0.35 seconds (internal measurement on vehicle with automatic transmission), which is about half of the time taken by conventional starter-motor idling stop systems."
Very interesting. I just reviewed the Mazda website and read more about the technology. I'm wondering, can you still turn off this start/stop feature if you want to?

dbr
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Re: Subaru Outback engine stop/start

Post by dbr » Sat Jan 25, 2020 1:21 pm

Having to engage and run a starter at every stop is a pretty clunky solution to a problem. It stands to reason better solutions will appear. Also, electric cars do not have this issue though I wonder how much less efficient an electric motor is for starting from stop compared to constant speed running. At least an electric presumably does not draw current while stopped and braked.

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TomatoTomahto
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Re: Subaru Outback engine stop/start

Post by TomatoTomahto » Sat Jan 25, 2020 2:03 pm

dbr wrote:
Sat Jan 25, 2020 1:21 pm
I wonder how much less efficient an electric motor is for starting from stop compared to constant speed running.

just whatever physics and aerodynamics indicate. A heavy foot on the accelerator has a cost to tires and energy consumption. At least an electric presumably does not draw current while stopped and braked.
just draw for lights, heat-cooling, running the CPU, radio, etc., so minimal
Okay, I get it; I won't be political or controversial. The Earth is flat.

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Re: Subaru Outback engine stop/start

Post by JAZZISCOOL » Sat Jan 25, 2020 2:10 pm

Re: Mazda's in the US / stop/start

FWIW the i-STOP isn't on US models yet (as of 2018?):

https://www.mazdas247.com/forum/index.p ... 123865268/

It seems like they have it in Australia, etc.

Millennial
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Re: Subaru Outback engine stop/start

Post by Millennial » Sat Jan 25, 2020 2:32 pm

TheGreyingDuke wrote:
Thu Jan 23, 2020 7:22 pm
As a lifelong manual transmission person, I am contemplating purchasing what may be the last such vehicle, I assume that this technology is NOT available on a stick?
It actually is present on some stick shifts, and (as a lifelong manual driver myself) I would suggest the implementation is much better on a manual, as it only shuts off the engine when when are stopped, put the car in neutral, and let out the clutch. As soon as you touch the clutch to put it back in gear, it restarts the engine.

This gives you total control over the stop/start system. Know you're only stopping for an instant and don't want the engine off? Great - leave it in gear with the clutch depressed. Pulling up to a light that just turned red, so you know you're sitting for a bit? Go to N to turn it off.

The best part is that unlike an auto which can't start the car until you basically start moving, with a manual it starts it while you're pushing in the clutch, so by the time you want to hit the gas it's started. Much more seamless, IMO, than an automatic which can have a bit of a pause.

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Re: Subaru Outback engine stop/start

Post by iamlucky13 » Sat Jan 25, 2020 2:39 pm

onourway wrote:
Fri Jan 24, 2020 6:19 am
If this feature is noticeable enough that you are complaining about it - it’s the fault of the manufacturer who has implemented it poorly. Drive a Toyota Prius of any age and this feature will hardly be noticeable, even if you are paying attention. And it happens far more frequently in a hybrid like that, and I don’t think I’ve ever heard of anybody complain of starter problems on a Prius or any other issues regarding from excessive wear and tear because of it.
As a hybrid, the Prius has a much larger electric motor that serves dual role as both starter and part of they power for driving. This is more expensive, but helps make the start-stop operation nearly seamless.

For non-hybrid cars, start-stop is implemented with a starter closer in size to a non-start-stop car. It's noticeable, but I've found to be a non-issue. When I've rented cars with the feature, I quickly stopped noticing it unless I was thinking about it.

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Re: Subaru Outback engine stop/start

Post by Millennial » Sat Jan 25, 2020 2:40 pm

dbr wrote:
Sat Jan 25, 2020 1:21 pm
Having to engage and run a starter at every stop is a pretty clunky solution to a problem. It stands to reason better solutions will appear. Also, electric cars do not have this issue though I wonder how much less efficient an electric motor is for starting from stop compared to constant speed running. At least an electric presumably does not draw current while stopped and braked.
I think the "better solution" you mention is an electric car.

What makes you think an electric car is less efficient for getting a car moving than a gas engine?

dbr
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Re: Subaru Outback engine stop/start

Post by dbr » Sat Jan 25, 2020 2:47 pm

Millennial wrote:
Sat Jan 25, 2020 2:40 pm
dbr wrote:
Sat Jan 25, 2020 1:21 pm
Having to engage and run a starter at every stop is a pretty clunky solution to a problem. It stands to reason better solutions will appear. Also, electric cars do not have this issue though I wonder how much less efficient an electric motor is for starting from stop compared to constant speed running. At least an electric presumably does not draw current while stopped and braked.
I think the "better solution" you mention is an electric car.

What makes you think an electric car is less efficient for getting a car moving than a gas engine?
I don't think an electric car is less efficient than a gas engine car for acceleration. Actually I don't know about that one way or the other.

I am referring to the fact that an electric motor draws a lot of current and dissipates a lot of wasted energy as heat when it runs at low revolutions and high load. That means electric propulsion does not automatically evade the problems of wasted energy in stopping and starting. What It does evade is wasting energy while it is stopped. It may also evade wasting energy as heat in the brake system if the retarding system can save energy back into the battery. But all this depends on the exact engineering of the electrical system.

In any case electric is probably better technology for this problem all around.

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Re: Subaru Outback engine stop/start

Post by RootSki » Sat Jan 25, 2020 2:49 pm

iamlucky13 wrote:
Sat Jan 25, 2020 2:39 pm
onourway wrote:
Fri Jan 24, 2020 6:19 am
If this feature is noticeable enough that you are complaining about it - it’s the fault of the manufacturer who has implemented it poorly. Drive a Toyota Prius of any age and this feature will hardly be noticeable, even if you are paying attention. And it happens far more frequently in a hybrid like that, and I don’t think I’ve ever heard of anybody complain of starter problems on a Prius or any other issues regarding from excessive wear and tear because of it.
As a hybrid, the Prius has a much larger electric motor that serves dual role as both starter and part of they power for driving. This is more expensive, but helps make the start-stop operation nearly seamless.

For non-hybrid cars, start-stop is implemented with a starter closer in size to a non-start-stop car. It's noticeable, but I've found to be a non-issue. When I've rented cars with the feature, I quickly stopped noticing it unless I was thinking about it.
I believe that electric motor is called an Crankshaft Intergrated Starter Generator or CISG or sometimes just ISG. They provide the smoothest re-starts.

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Re: Subaru Outback engine stop/start

Post by iamlucky13 » Sat Jan 25, 2020 3:10 pm

smalliebigs wrote:
Fri Jan 24, 2020 5:40 pm
Regarding the comments on manual transmission and cost to repair the 8-speeds. The sales information that all OEMs have now indicate that most buyers of new cars lease, rather than buy. Thus, for most buyers, it won't be their problem with regards to repair. This is the advantage of leasing that the market is just leaning on, in addition to the lower monthly costs. Whether or not you agree is another matter. Add to the fact that if you want a new car, 95+% of new cars sold are automatic transmissions. So that is the norm now.
Around 1/3 of new cars are leased, not a majority:
https://www.edmunds.com/about/press/num ... dscom.html

And once the leases are up, most of them are sold, not re-leased. As a result, the overwhelming majority of cars are directly owned. I didn't find clear numbers, but it sounds like around 15 million leases are currently active, out of a total of nearly 200 million passenger cars in the US.

The anticipated cost of future repairs factors into resale prices, which in turn is a major factor in setting lease rates, so while this is not directly the problem of most new car buyers, it does affect them.

The fact that 95% (probably more, actually) of new cars have automatic transmissions isn't very informative about cost to repair, aside from the ubiquity of automatic transmissions has helped bring the cost premium down.
RootSki wrote:
Thu Jan 23, 2020 8:36 pm
Manual transmissions are irrelevant in the era of 8 and 10 speed dct’s. They are fun and you do feel connected to the power train, for a daily driver, I’ll take more gears over a stick any day.
They're not at all irrelevant, although if I had to take an automatic transmission, I'd definitely give dual clutch versions close consideration, assuming I can find one in my price range that meets my other needs. This forum often seems to forget that most of us are not driving BMW's, and I haven't been hearing good things about the reliability of DCT's in budget cars like the sport versions of the Fiesta or the Korean compacts.

Regardless of that, fast shifts aren't the only reason for seeking out manual transmissions. All of the automatic transmissions I've driven, including CVT's, fairly regularly end up a in less-than-ideal gear ratio, and none of them can anticipate the driver. I personally find this much more tedious than the routine of shifting that many people complain about - it's not like doing so prevents me from doing something else anyways, although I do see plenty of people around me who would have to stop texting for a moment to shift.

And I have never gotten the knack of rocking a car out of the snow with an automatic transmission, at least not the same way I can in a manual.

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Re: Subaru Outback engine stop/start

Post by JonnyB » Sat Jan 25, 2020 3:29 pm

dbr wrote:
Sat Jan 25, 2020 1:21 pm
I wonder how much less efficient an electric motor is for starting from stop compared to constant speed running.
Electrical losses go up with the square of the acceleration. So a heavy foot wastes a lot more energy and lowers your miles per KWh substantially.

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Re: Subaru Outback engine stop/start

Post by JonnyBeRetired » Sat Jan 25, 2020 4:14 pm

I had our 2019 Outback in for service yesterday and the dealer provided a 2020 Legacy as a loaner. The Legacy has the same feature and I drove it around the suburbs for about two hours, so plenty of stop signs, stop lights, trains, etc. The auto start stop feature kicked in at least twenty times. Once, while waiting for a train, I shifted in my seat and inadvertently mashed in the brake pedal - the engine restarted. I tried it again before turning onto a busy road and waited with the engine running before the turn. This probably eliminated my biggest question/concern about the feature. Overall the stops and starts were fairly smooth and quiet - though my perspective on quiet might be suspect since previously we drove a 2009 Prius which at times was silent and at times was like driving with R2D2.

Here’s an excerpt from the 2020 Outback manual - page 363.
Non-operational conditions
In any of the following cases, the Auto Start Stop system will not operate.
. When the Auto Start Stop warning light/ Auto Start Stop OFF indicator light is illuminating.
. When the malfunction indicator light (Check Engine light) is illuminating.
. The electronic parking brake is applied.
. When the engine hood is opened.
. When the vehicle is at an altitude of more than approximately 10,000 ft (3,000m).
. When the CVT fluid is not sufficiently warmed up.
. When the temperature of the CVT fluid is abnormally high.
. When the vehicle battery is not in good condition.
. When using the climate control system, the temperature difference between the setting temperature and the temperature inside the vehicle is significant.
. When using the climate control system, the amount of air flow is significant.
NOTE: The Auto Start Stop system may not operate if the malfunction indicator light (Check Engine light) or other warning lights on the combination meter are illuminating.

Engine restart operational conditions
In any one of the following cases, the engine will be automatically restarted even if the brake pedal is kept depressed.
. When slightly releasing the brake pedal on road with a steep slope and the vehicle begins rolling.
. When further depressing the brake pedal.
. When depressing the accelerator pedal board.
. When you move the select lever to the “R” position.
. When turning the steering wheel.
. When operating the electronic parking brake switch.
. When activating the X-MODE (if equipped).
. When the air flow mode selection set to “[defrost]” mode.
. When the climate control system can no longer maintain the set temperature.
. When opening the power rear gate automatically.
. When unbuckling the driver’s seatbelt.
. When trying to open the power rear gate automatically.
. When opening the driver’s door.
. When activating the rear window defogger.
. When the Auto Vehicle Hold function is released, refer to “Auto Vehicle Hold function” FP357.

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