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1. No matter how the system is designed, more frequent starts generate more wear. And having a more robust starting system adds weight and expense.
2. The system can still cause delays at critical times, and just be disorienting, especially for those of us who learned to drive cars that stay on.
3. Some of us resent government mandated annoying things, no matter the intent.
I realize that Porsche has to comply with US federal BS (and in other countries), but we should stop pretending that something like auto stop-start is "better".
+1 and engine start generates more wear on the engine itself. Oil distribution is less effective, vibrations, etc.
Little gas savings isn't worth it. You consume way more gas just by your spirited driving.
Also having clutch pressed long time during traffic stop while keeping the car in a gear isn't very good idea either, as it wears out the clutch bearing.
Last edited by Papa Fittig; 03-09-2018 at 03:43 AM.
Long answer: the starter motors are designed differently than traditional starters, the engine electronics work with the starter to position the cylinders optimally, and the solenoid that engages the mechanical connection to the flywheel is decoupled from the electrical circuit required to start and stop the starter motor. I know some manufacturers rely on a second starter motor for start/stop, but I believe Porsche does it with a single system.
That sounds like a nice explanation from an engineer who wishes to keep or further their position at Porsche where the engineers are NEVER wrong and ALWAYS have the customers best interest at heart ....
Bottom line : Start stop “ technology “ sacrifices the longevity of the drivetrain and electrical system components of a vehicle for fractional benifits in fuel savings and reduction of emissions.
You want to help preserve the environment long term ? That’s fine , plan your trips better and reduce the miles driven.
You want to help preserve your vehicle long term ?
Turn that rediculous system OFF!
I’m working on a series of posts, here are the titles:
1) When less is more, the vast superiority of two pedals
2) The Panamera is the greatest automotive achievement in history
3) How turbos blow out every argument in favor of NA
4) Why steering wheels when the car can do all the work?
5) PCCB should be standard equipment!
6) Electrification is electrifying
Originally Posted by blepski
That sounds like a nice explanation from an engineer who wishes to keep or further their position at Porsche where the engineers are NEVER wrong and ALWAYS have the customers best interest at heart ....
Bottom line : Start stop “ technology “ sacrifices the longevity of the drivetrain and electrical system components of a vehicle for fractional benifits in fuel savings and reduction of emissions.
You want to help preserve the environment long term ? That’s fine , plan your trips better and reduce the miles driven.
You want to help preserve your vehicle long term ?
Turn that rediculous system OFF!
You want to help preserve your vehicle long term ?
Turn that ridiculous system OFF!
^^^ This.
Even though the engine is warm, the oil stops circulating when the engine is off. Every startup is just a tiny bit drier than if the engine (and turbos) remained on. Every start causes at least some reduction in starter life.
By no means do I pretend to have any technical knowledge of the auto Start/ Stop feature. If it was so damaging long term to the engine and other systems, wouldn’t Porsche and other hi end Manufacturers leave themselves open to a bunch of class action suits down the road?
By no means do I pretend to have any technical knowledge of the auto Start/ Stop feature. If it was so damaging long term to the engine and other systems, wouldn’t Porsche and other hi end Manufacturers leave themselves open to a bunch of class action suits down the road?
They may have a better starter design...but the more things are used the more likely it will wear out and fail. Use it or loose it does not apply in this case.
abe
I had a brand new BMW convertible rental car last summer. Not sure what series is was but in any event, the auto start-stop function was not nearly as slick as that in the 911. There was much more of a start-up lag with release of the brake in the BMW. Also, the "economy" mode in the BMW had very little pep in its step. Did not feel like a sports car. On the contrary, although the 911's normal mode is not stupendously powerful - and it is not supposed to be - I do find it can be remarkably powerful if you step on it. It definitely comes to life if you hit the gas. This is off-topic but what is the "difference" between normal and sport mode? I know about the engine mounts, etc. But what actually happens in the engine? The individual gears shift at a higher rev range but is that all it is? Is the engine just revving more? This may be engine mechanics 101 but I have wondered ever since I got a 911 what exactly changes with the engine dynamics when sport mode is hit? Back on topic - the auto start/stop works fantastically on the highways. It is amazing how fuel efficient the car can be on the highway. In my prior Jaguar XKR, I don't think I could make it from LA to Vegas on a single tank (it is a V8 engine - no cruise mode or auto start/stop function). In my 991.1 GTS, I can get to Vegas on 2/3 of a tank. Kudos to the 991 engineers - they built one hell of a car.
By no means do I pretend to have any technical knowledge of the auto Start/ Stop feature. If it was so damaging long term to the engine and other systems, wouldn’t Porsche and other hi end Manufacturers leave themselves open to a bunch of class action suits down the road?
It depends on your time horizon and ability to prove the feature was the cause. And no one is saying that the system is hugely damaging. The express new car warranties run out after 4 years, 50,000 miles (or something like that). A CPO can go up to 6 years from the date of first sale or 100,000 miles. Beyond that, it would be hard to lay claim to any warranty breach. If your car starts losing compression due to wear after 100k miles, or consuming oil, are you really going to be able to prove that it was caused by the larger number of start/stops vs. some other cause? Many owners are likely to sell their cars short of 6 years/100k miles, but in the Porsche world, a fair number keep them longer than that, or own them into the second 100k having purchased them used. So I suppose unless you owned the car from new, and could be certain you either used the feature or not used it, it would be hard to prove it was the system that caused the wear and not ill-maintenance or some other cause.
And there are those of us who just want to, within reason, do what we can to keep our cars as fresh as possible while still using them. Giving up some small measure of fuel economy by turning off Start/Stop seems worth the extra longevity, but obviously the trade-offs aren't for everyone. Probably all this is only theoretical either way, as I can't see use or non-use making that much difference in wear or economy except over the course of 100k miles or more.
03-09-2018, 12:27 AM
