Stop Sale Campaign on 911 with Sport Chrono?
12-08-2020, 01:10 PM
#466
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12-08-2020, 01:24 PM
#467
Same here, at first I thought it may be a coincidence but after thinking about it the feeling is they know what I have so maybe not.
12-08-2020, 01:29 PM
#468
I got 1 or 2 emails like this over the summer and thought it was because of low inventory and high demand.
On the original question, I may have missed it in the 400+ posts but I still don't understand what it is that SC does differently with regards to emissions, especially on cars with manual transmission...
On the original question, I may have missed it in the 400+ posts but I still don't understand what it is that SC does differently with regards to emissions, especially on cars with manual transmission...
12-08-2020, 01:32 PM
#469
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12-08-2020, 02:48 PM
#470
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If you ignore my foaming at the mouth here ——^ therein lies a summary of the answer.
A summary from another angle is that all modern cars control, to a fair-thee-well, the air fuel ratio to a degree that, prior to computer controlled everything, was impossible but are now required to make emissions numbers. However, consequences of that is poor throttle response, inability to rev match downshifts, and ‘deterrents to accelerating’ in the mapping between foot and throttle plate. Thus, enabling any car to exhibit the characteristics that we associate with sports cars ipso facto increases emissions minutely during testing and somewhat less minutely when we, sport car drivers, make use of those characteristics. Under any circumstances hard acceleration will “blow the test” and, for turbocharged cars, any use of the engine under boost blows the test even more so. Keep in mind that government testing is not just a sniffer at idle. It involves varying loads and varying speeds to simulate ‘round town and highway use. In today’s emissions testing environment acceleration must be frustratingly gentle in order to make numbers,
For PDK, emissions are reduced by enforcing a strategy of gear changes that keep the engine at a speed as close as possible to it’s lowest specific fuel consumption. (SFC is fuel-mass/hp units.) With modern computer control of direct injection engines that point is ~1200 rpm(-ish). But, there’s no torque available there. To “feel sporty” you want engine speed closer to torque (higher.) So you change the shift strategy of the PDK in S/S+ mode to keep engine speed higher. And thereby “blow” the emissions test.
Realize that a ‘user-controlled’ throttle pedal is thus an emissions cheating device.
Engine temperature also plays a role. 220(-ish)°F engine temperature results in a different mix of pollutants than does 195°. However, modern catalytic converters can clean the former, not the latter. The problem, of course, with 220°F temperature is that you’re already relying on the coolant to keep the engine from exploding so you don’t have a lot of margin for horsepower production in excess of capacity to cool. And cooling capacity doesn’t change instantly.
Some people seem to think that EPA/EU testing is about keeping horrible polluting cars - like early 70s era V8s with no cats - off the road. It stopped being about that a decade ago when cars, warmed up, driving at a steady speed exhausted air that was cleaner that what was being ingested. After that, increasing the stringency of tests started becoming political. When a system like automatic stop/start is required to make numbers you have to ask if “things have go too far.”
Last edited by worf928; 12-08-2020 at 03:14 PM.
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12-08-2020, 02:50 PM
#471
12-08-2020, 05:30 PM
#472
I’m not expecting much but going to find out first hand and maybe get some more details.
12-08-2020, 06:10 PM
#473
https://rennlist.com/forums/991/1222...l#post17031563
If you ignore my foaming at the mouth here ——^ therein lies a summary of the answer.
A summary from another angle is that all modern cars control, to a fair-thee-well, the air fuel ratio to a degree that, prior to computer controlled everything, was impossible but are now required to make emissions numbers. However, consequences of that is poor throttle response, inability to rev match downshifts, and ‘deterrents to accelerating’ in the mapping between foot and throttle plate. Thus, enabling any car to exhibit the characteristics that we associate with sports cars ipso facto increases emissions minutely during testing and somewhat less minutely when we, sport car drivers, make use of those characteristics. Under any circumstances hard acceleration will “blow the test” and, for turbocharged cars, any use of the engine under boost blows the test even more so. Keep in mind that government testing is not just a sniffer at idle. It involves varying loads and varying speeds to simulate ‘round town and highway use. In today’s emissions testing environment acceleration must be frustratingly gentle in order to make numbers,
For PDK, emissions are reduced by enforcing a strategy of gear changes that keep the engine at a speed as close as possible to it’s lowest specific fuel consumption. (SFC is fuel-mass/hp units.) With modern computer control of direct injection engines that point is ~1200 rpm(-ish). But, there’s no torque available there. To “feel sporty” you want engine speed closer to torque (higher.) So you change the shift strategy of the PDK in S/S+ mode to keep engine speed higher. And thereby “blow” the emissions test.
Realize that a ‘user-controlled’ throttle pedal is thus an emissions cheating device.
Engine temperature also plays a role. 220(-ish)°F engine temperature results in a different mix of pollutants than does 195°. However, modern catalytic converters can clean the former, not the latter. The problem, of course, with 220°F temperature is that you’re already relying on the coolant to keep the engine from exploding so you don’t have a lot of margin for horsepower production in excess of capacity to cool. And cooling capacity doesn’t change instantly.
Some people seem to think that EPA/EU testing is about keeping horrible polluting cars - like early 70s era V8s with no cats - off the road. It stopped being about that a decade ago when cars, warmed up, driving at a steady speed exhausted air that was cleaner that what was being ingested. After that, increasing the stringency of tests started becoming political. When a system like automatic stop/start is required to make numbers you have to ask if “things have go too far.”
If you ignore my foaming at the mouth here ——^ therein lies a summary of the answer.
A summary from another angle is that all modern cars control, to a fair-thee-well, the air fuel ratio to a degree that, prior to computer controlled everything, was impossible but are now required to make emissions numbers. However, consequences of that is poor throttle response, inability to rev match downshifts, and ‘deterrents to accelerating’ in the mapping between foot and throttle plate. Thus, enabling any car to exhibit the characteristics that we associate with sports cars ipso facto increases emissions minutely during testing and somewhat less minutely when we, sport car drivers, make use of those characteristics. Under any circumstances hard acceleration will “blow the test” and, for turbocharged cars, any use of the engine under boost blows the test even more so. Keep in mind that government testing is not just a sniffer at idle. It involves varying loads and varying speeds to simulate ‘round town and highway use. In today’s emissions testing environment acceleration must be frustratingly gentle in order to make numbers,
For PDK, emissions are reduced by enforcing a strategy of gear changes that keep the engine at a speed as close as possible to it’s lowest specific fuel consumption. (SFC is fuel-mass/hp units.) With modern computer control of direct injection engines that point is ~1200 rpm(-ish). But, there’s no torque available there. To “feel sporty” you want engine speed closer to torque (higher.) So you change the shift strategy of the PDK in S/S+ mode to keep engine speed higher. And thereby “blow” the emissions test.
Realize that a ‘user-controlled’ throttle pedal is thus an emissions cheating device.
Engine temperature also plays a role. 220(-ish)°F engine temperature results in a different mix of pollutants than does 195°. However, modern catalytic converters can clean the former, not the latter. The problem, of course, with 220°F temperature is that you’re already relying on the coolant to keep the engine from exploding so you don’t have a lot of margin for horsepower production in excess of capacity to cool. And cooling capacity doesn’t change instantly.
Some people seem to think that EPA/EU testing is about keeping horrible polluting cars - like early 70s era V8s with no cats - off the road. It stopped being about that a decade ago when cars, warmed up, driving at a steady speed exhausted air that was cleaner that what was being ingested. After that, increasing the stringency of tests started becoming political. When a system like automatic stop/start is required to make numbers you have to ask if “things have go too far.”
Still wonder why MT are impacted like PDK cars in this, given that a big component of the S/S+ modes only works on PDK cars (the shift at higher RPMs, which you explain above).
12-08-2020, 06:55 PM
#474
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There is an ‘upshift’ light on MT cars the activation of which may be affected by mode. I’ve never cared to observe if that is true.
Note that the inherent “issues” with S/S+ modes may be a non-issue vis-a-vis the EU investigations and the US CA lawsuit if indeed Porsche actually made hw/sw changes to vehicles to be tested. When Dieselgate hit I disbelieved that any corporation could be stupid enough to actively, with malice aforethought, cheat on emissions testing. I was wrong. At this point, for me, it’s a case of “hear all, believe nothing.”
12-08-2020, 07:20 PM
#475
So, are we to believe that the testers were blind to the fact that Sport/Sport Plus even existed? Hard to comprehend how someone could rigorously test a new vehicle and not be aware of the entire operating range.
Then again, we are, in fact, talking about the gubmint.
Then again, we are, in fact, talking about the gubmint.
12-08-2020, 07:40 PM
#476
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What I do not know is if EU/EPA/CARB regulations require the test protocol be conducted for any non-default driving mode. I would bet against this.
For instance, AS/S went from defaulting to last-used mode to always on at startup due to testing regulations, For the same reason, normal is the default mode upon startup and Sport/Sport+ have - at least for 9[98]1 - always defaulted to off at startup.
12-08-2020, 07:42 PM
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12-08-2020, 07:44 PM
#478
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12-08-2020, 09:02 PM
#479
I guess my question is, what is the purpose of the test protocol if everything is basically out the window with the simple push of a button? I can see it now: (test official): "Congratulations Porsche, your model 991 passed with flying colors. One quick question though, what is the function of the console buttons labeled "Sport" and "Sport Plus"? (Porsche official): "So sorry. That is Porsche proprietary information."
12-09-2020, 12:03 AM
#480
But then a lot of other models and brands would have the same issues...