AnandN

verstraete

If it meets government emission regulations, and I can legally drive it on the street, that's good enough for me.

Churchill

Of course. Don't install cat bypass pipes. But I still am not understanding the point of this public self-shaming. If you don't like the emissions of your 911, get a different car. What is there to discuss?

bkrantz

Besides the fact that even vehicles that rank only 1 are much cleaner than average emissions from a decade ago, the numbers of vehicles is also significant. Porsche sold 8900 911 models of all variants. Honda sold 700,000 Accords and Civics in 2017. We could run our 911's all with unrestricted engines and not even make a blip in the total emissions of all the Hondas.

Randy M

Trump will get the EPA to relax standards. He's already going after CARB.

ipse dixit

So you discovered this emissions "issue" with the 991.2 before or after you bought your 2018 C4S?

If it was the latter, I think you have bigger issues to worry about (with yourself) than emissions standards..

If it was the former, then the person you need to speak with is in the mirror.

911-TOUR

It's still 30% cleaner than my 1995 993. And get's much better mileage. And makes 100 HP more. I'll take it.

PJ Cayenne

Must have something to do with 400hp and 0-60 in under 4 seconds. I traded my V8 Mercedes and Twin V8 Cruisers Yacht for the 911. I used to use more gas in one weekend in the boat than a full year in the 911. I am much happier with the 911 than the boat and can truly claim a lower carbon footprint.

stout

Eh, all comes down to how you use it.

Yes, high emissions compared to a car of similar weight and size that emphasizes fuel economy (as most do). But, VERY low emissions against cars of not long ago—even those that made less power. Also sips gas compared to Porsches I've had in the past, and the old one in my garage.

As for at delete, well, what a bummer. And for no useful hp gain.

AnandN

One can like something a lot and still be critical of its shortcomings. How hard is that to get? I will ignore the asinine comments posted by those who can't stand to read anything negative about the 911.
Porsche went to turbo sixes for emissions. They did improve the CO2 emissions (in theory) somewhat but apparently not (the more stringent) smog-causing emissions. So the purpose of the engineering exercise was probably for performance gains and not emissions as stated by Porsche. And to get around the pesky taxes levied on engine displacement in certain countries. What I can conclude. Nothing wrong with that. But other high performance small cars do seem to fare somewhat better. Just something to remember when going shopping for a high performance car if one cares for such things. Did I know about the emissions before I bought my car in 2017? Only the fuel economy numbers but the smog ratings were not published for 2018 cars. Would it have affected my decision to buy the 911? Honestly don't know. I may have kept my 13 Boxster S which did not see as much use as my 911 which is rapidly acquiring DD status. Am I regretting my purchase? Not really but I do wish it had better real world fuel economy & better emissions. Almost everything else is perfect for my driving needs.

Anyway, this was simply a byproduct of my interest in aftermarket exhaust systems. I could not find any information on how these systems affect emissions. Hence my interest in bringing it up. There is no reason to get bent out of shape by it.

Valvefloat991

It's worth remembering that the emissions requirements for 2018 were upgraded from Tier 2 to Tier 3 standards, which are more strict. As a result, the 991.2 engine, which seems unchanged from the 2017 to the 2018 models, dropped in its smog rating from 5 to 1. I suspect that this will be rectified with the 992 models. However, with the 911 emissions being blended into the mix for all of the VW vehicles, this small difference is irrelevant. For comparison, the Base Corvette is also rated 1, however, the F-type S is a 5 and the AMG GT is a 7. By the way, these ratings are absolute and not compared to other vehicles of its size and weight. And a 911 from the Sixties probably produces the smog emissions of a hundred 991.2s.

As to the real world fuel economy, the 991.2 is clearly better than the 991.1, if the car is driven to exploit its greater low-rpm torque and taller gearing. Of course, if you belong to the 7th gear-is-unmanly crowd, or keep your revs above 4000 even in rush-hour traffic, you probably won't realize the improvement. In this regard, however, the 911 is better than the three competitors above, with a 5 rating, while the others are all rated 3.

Aatish

SMOG rating system/criteria change every couple years or so.
With the drastic change in the administration, chances are the EPA also have a drastic change in their criteria for SMOG ratings.


Now, from an engineers point of view, emission levels are measured by the level of CO2 being outputted from the motor during operation.
A 2014 Carrera 3.4L outputs roughly 191 g/km of CO2.
A 2018 Carrera 3.0l Turbo outputs roughly 169 g/km of CO2.

Can't find the other levels (like n02, CO, etc) but I'd assume that those levels are also lower for the turbo car, than the N/A car.

http://www.emissionsfinder.com/porsc...dk-euro-6-35cc
http://www.emissionsfinder.com/porsc...dk-euro-6-35cc

AnandN

Aatish

Not to come off as aggressive or trollish, but what are you trying to get at with the emissions from the Porsche and exhaust systems?
I just looked at the figures for a 2018 Tahoe, a 2018 Carrera C2, and a 2016 Carrera C2. The Tahoe is far more inefficient, and pollutes a lot more than the Porsche. It also have a lower rating...

Genuinely curious as to what your stance is on this view, and your thinking behind your comments . I put a smiley face cuz I'm not trying to be a dick...


Interms of exhaust systems, modifications after the cats will not affect the output emitted by the engine. From my initial inspection of the system (was taking measurements), there are no secondary cat structures to be found...
This would indicate (to me at least) that the stream after the CATs would be of similar quality to that of the stream after the tailpipe.

From my research, Fabspeed X-pipe would be your best bet if you wanted more sound without affect the output levels. A 200 HJS cell CAT (like those found in performance CATs from Soup PP or Fabspeed) are going to scrub the exhaust gases to a level that is deemed acceptable by the ECU (hence the no CEL).

That said, they might not be scrubbing and outputting to the level that the EPA would like....
Personally, I really don't view on the same level as the EPA...so I probably will go sooner or later (probably sooner). But lets not get onto my views.

What I'm saying is, if you want more sound without effecting the emissions output of the car, then focus on mods after the cats. Shouldn't affect the levels outputted. Will definitely help sound, cuz that muffler seems quite effective imo.

AnandN