Here is the thing I don't believe for paying for technology that you don't use; it's against my principles. Which brings me to the Auto Start-Stop function.

I love the fact that it disengages the transmission when coasting, because less moving parts leads to less friction and results in longer life for the tranny.

On the other hand, when stopped at the light, the start-stop will reduce the life of the starter, and all other parts that have to go on, off, on, off, on, off.

And by the way, I am not so concerned about fuel savings; no sense in being penny wise, pound foolish.

So I am really interested in your technical/critical thinking and comments/opinions/knowledge in this topic.

Thank you.

 

We have it on our 4 series and the very first thing I do when I seldom do drive it is put it in sport mode to bypass it. Can't help you with the technical of it but I'm with you start/stop sucks IMO.

 

Have it turned off on my 991S, my Macan Turbo and Audi S5. It bothers me at stop lights etc.

 

On ours it's generally turned OFF. However, I think for long drives involving no red lights, I would probably turn it ON because I really like the coasting feature. It's the same as putting a manual gearbox in Neutral when going down hill or getting ready to stop.

At the red lights, I imagine that every time it turns off, it's not only the starter that you need to worry about going bad. There is also the oil pump, fuel pump, air pumps, etc., etc. that go on and off and that is not good IMO. I am no electrical engineer but I believe that electrical equipment have a set number of 'on and offs' before they just cave. Auto Start-Stop will help you burn through that set number much more quickly. Most likely, big daddy Porsche isn't going to pay for any related repairs/replacements because you're probably not going to burn through those set number of 'on and offs' in the first 50K miles.

 

I am glad that you posted this. I am also worried(?) about it and plan to turn it off, completely. No matter how you look at it, repetitive on-and-off cycle will wear out components over time.

 

I agree that paying for what one doesn't want is objectionable -- but sadly, inavoidable in so many things these days. Porsche is better than most in offering individual options instead of forcing one to buy bundles of things he doesn't want in order to get one he does.

But regarding the Auto Start/Stop function, it sounds like it's Porsche's implementation that is the issue, not the fact that it is available for you to use.

Porsche chose to implement this complex function to achieve marginally better fuel economy instead of working hard to make the Macan fundamentally more efficient. There's no reason, for example, that the Macan S couldn't have been offered with a naturally aspirated V6. Also, a 200 kg diet would have accomplished more for both economy and performance, IMHO. Anyway, now that we all have AS/S, the question is whether to use it or not. If you don't like the way it makes the Macan feel/sound/respond, then don't. Your gas money, your choice.

To the larger issue you touched on, I recommend that longevity/reliability is an area where Porsche has already demonstrated that it knows what it is doing. Smarter people than I can confirm this, but I strongly doubt that it's the same starter/alternator used for models without the AS/S function. It's certainly beefed up, properly engineered to last just as long as anything else under the bonnet. Besides, if you think that using a standard function of the Macan like AS/S would lead to premature problems, then do you also turn off the HVAC? Do you keep engine RPM below 3000 at all times? Do you restrict your speed and lateral acceleration around corners to granny-like limits? Why worry about AS/S when the wear and cost of brakes, tires, and other normal functions of the vehicle endure are real & obvious?

If you choose to drive like a saint with no particular place to go, then you will achieve better vehicle longevity, and the opposite is true as well. Overall, it's probable that AS/S has negligible impact. But since you have decided to own a Porsche, then my recommendation would be to use its capabilities well, including the Start/Stop, to the fullest extent you desire.

By the way, I'm disgusted that Porsche is not offering a manual transmission, which saves weight & cost, enables coasting, and in general would be vastly more reliable/long-lifed than any electronics that any manufacturer puts into a car. I am actually disappointed more in being forced to have the PDK more than I am in having to buy Auto Start/Stop.

 

roule...Thank you for your reply. Here are my thoughts:

Bingo! Ding, ding, ding, ding!!!!!

Different starter, most probably. Different alternator, oil pump, fuel pump, etc., highly unlikely.

Well, we're still in Break-In period so we drive like a saint for now. But afterwards .... ... once in a while anyway.

Couldn't agree with you more but as this is my wife's car, it would be highly desired rather than acquired for me. Anyway, I do have my 911 and that one is stick.

 

Always off.

Not because I'm worried about the starter but because it's annoying and I'm not concerned about fuel savings. It's also almost always in Sport or Sport Plus, which would disable it if it was on.

 

I think it's a good system, and mine is almost always on. The Coasting feature is just too good. And being used to it in my cars, it feels sort of wasteful and "old school" to have an idling motor at a light (probably the same line of thinking albeit vastly more extreme that EV guys all seem to have toward gassers in general). Only annoying parts are how it often will immediately turn off when you stop to put it in reverse to back into a spot. Completely wasting an off/on cycle. That annoyance and any other immediate off/on's annoy me as I too don't like using up things that I don't need, so in that respect, the feature can be considered more of a burden.

That said; Porsche surely tested and built the car to be capable to handle the AS/S, and it takes in many variables to ensure it's "safe" to engage (you'll notice how sometimes it won't activate at a light for this reason). Also, the technology is used by many others as well.

I always wondered if the constant disengaging of the tranny could also bring its own form of "wear", but you stating the less moving parts and friction reducing wear makes sense.

And I too am very happy about Porsche's optioning structure, allowing you to specifically build a'la carte options of your choosing, together. Rather than be forced to pay for a bunch of nonsense that only add pointless weight and that you don't need.

 

This is the part that bothers me about AS/S the most. Sometimes when I come to a stop it'll kill the engine and immediately (as in a fraction of a second later) restart it. If it was going to do that, why bother with the shutdown at all? It's not like I changed any inputs to restart the engine -- no turning the wheel, no touching the accelerator, etc.

The system in the Panamera loaner I had a while back was much more refined and smoother than the one in the Macan.

I put up with the Macan's system because the coasting feature makes the car behave more intuitively when lifting off the throttle as I approach turns, traffic, etc.

 

Yeah that part drives me nuts. I.e the fractional second of a restart. Nothing good can come of that.

I'm considering putting the AS/S programmed into the "Diamond" wheel button (easy to do via your settings menu) so I can toggle it on and off quickly so it can work as I see fit. Not a carefree luxury approach, but I like pressing buttons and being in control in a Porsche anyway. Unfortunately where it's not intelligent is in sensing when you're parking, etc. so you kind of have to override it.

 

Not a bad idea! Use it when you want it. At the tip of your finger. Nice!

 

Dittos with my Cayman S. I'm not using it.

 

I was at a Mercedes dealer over the weekend and asked how their start-stop function worked. The salesperson said that the system notes which cylinder is at the top of its cycle when the engine stops (ie, which cylinder would be the next to fire.) When you step on the gas, that cylinder is the first to fire. The ignition is not enough to turn the entire engine over, but it's enough to get the next cylinder to fire, and so on and in short order the engine is running again. So no wear on the battery, starter, etc. Clever system, makes sense and seems to work fine. I assume Porsche and others use a similar system in their start-stop functions.

 

I've been driving a 2016 loaner the last couple of days and learned that you can't turn off the function for good. Every time you start the car, it reverts to default on. I find this very annoying especially since it turns off very quickly like within one second of stopping.