991.1 overrun (pops & crackles) vs none in gt3
06-29-2017, 06:30 PM
#16
Instructor
06-29-2017, 07:57 PM
#17
Instructor
On my 991.2 with PSE, there's backfires + pops from the exhaust only on Sports mode. On Sports+ there is none (that's the way it is programmed in my car at least).
06-29-2017, 08:11 PM
#18
On my car it sounds like flatulence and I find it deeply stupid and actually embarrassing when other people are present. I love the sound of the PSE. But the extended farting out the back (on my car it lasts 2-3 seconds) is ridiculous. What were they thinking -- hands-down the dumbest feature on the 991.
On early cars (I've owned many) with carburetors or MFI and no cats, you get the occasional crackle on decel, which is cool, because it's real. And it would be cool if Porsche simply replicated that phenomenon. But they had to make it cringe-inducingly fake. It's as dumb as installing a fake blow-off valve to make your Civic sound turbocharged.
On early cars (I've owned many) with carburetors or MFI and no cats, you get the occasional crackle on decel, which is cool, because it's real. And it would be cool if Porsche simply replicated that phenomenon. But they had to make it cringe-inducingly fake. It's as dumb as installing a fake blow-off valve to make your Civic sound turbocharged.
06-29-2017, 08:39 PM
#19
Instructor
06-30-2017, 07:14 AM
#21
Rocky Mountain High
Rennlist Member
Rennlist Member
I generally don't mind the overrun chatter from my 991.1 TTS, but it can be a bit obnoxious sometimes. I installed an FVD Brombacher cat-back exhaust, and that definitely made it louder. I find that the pops are very subdued or almost nonexistent in normal mode. They are a bit louder in sport mode, but they really become noticeable in sport mode or sport plus mode when I am manually shifting.
My understanding is that overrun chatter is normal in race cars because the timing is generally advanced in those cars for optimal performance at higher RPMs. The advanced timing causes more unburnt fuel to be sent into the hot exhaust system, causing the pops. I guess Porsche wanted to simulate racing car sounds with this feature.
My understanding is that overrun chatter is normal in race cars because the timing is generally advanced in those cars for optimal performance at higher RPMs. The advanced timing causes more unburnt fuel to be sent into the hot exhaust system, causing the pops. I guess Porsche wanted to simulate racing car sounds with this feature.
06-30-2017, 08:47 AM
#22
Race Car
While I admit it sounds cool, I can't get past knowing that it's computer induced. I'd pass on it.
It's even worse in the M2 where it's piped in thru the speakers!
It's even worse in the M2 where it's piped in thru the speakers!
06-30-2017, 10:01 AM
#23
06-30-2017, 08:33 PM
#24
Racer
I think this sounds very cool. Went for a ride in my friends Huracan and it was doing this...I had no idea why but it sounded awesome. In the back of my mind I was thinking this may or may not be optimal but who cares. I really think its cool...must be the 14 year old kid is this creaky near 60 year old body! LOL.
06-30-2017, 09:43 PM
#25
Here is an article that explains Jaguar's backfire technology.
"Jaguar engineers achieved this by defying convention. "Usually you’d cut the fuel to the cylinders, when the driver lifts off the accelerator," explained Andrew Lowis, the Gasoline Calibration Manager for the car. "We are delaying the point when we do that and igniting later than we might in normal circumstances. It produces a controlled misfire."
Obviously, the car must still meet emissions regulations despite the intentional introduction of pollutants to the exhaust stream. "It is a challenge, but it is one we can achieve by careful calibration," said Lowis. In fact, Jaguar has more stringent internal emissions limits than the government applies, he said, and the car meets those, too."
"'Theater' is a great word," noted Kevan Richardson, Program Manager for Jaguar sports cars. “We want the car to be entertaining. ... It is all part of the show."
"Jaguar engineers achieved this by defying convention. "Usually you’d cut the fuel to the cylinders, when the driver lifts off the accelerator," explained Andrew Lowis, the Gasoline Calibration Manager for the car. "We are delaying the point when we do that and igniting later than we might in normal circumstances. It produces a controlled misfire."
Obviously, the car must still meet emissions regulations despite the intentional introduction of pollutants to the exhaust stream. "It is a challenge, but it is one we can achieve by careful calibration," said Lowis. In fact, Jaguar has more stringent internal emissions limits than the government applies, he said, and the car meets those, too."
"'Theater' is a great word," noted Kevan Richardson, Program Manager for Jaguar sports cars. “We want the car to be entertaining. ... It is all part of the show."
07-01-2017, 03:04 AM
#26
It's all programming. Note that in normal, they are almost non-existent. In Sport there is more and in Sport plus it's like there is a cannon brigade behind you. The ECU is just choosing to add extra fuel to create these artificial backfires. Personally, and I know I'm in the minority, I think it sounds stupid. I wish there was a way to program it out.
The GT3 doesn't have this because it's not programmed in.
The GT3 doesn't have this because it's not programmed in.
And I might be crazy but it feels to me like at low RPMs the engine is more responsive with the valves closed? With a manual at least, put it in sport or sport plus, press the exhaust button to turn it off (which isn't off, just means keep them closed at lower RPMs), and compare to when it's on. This is also on the .1 GTS, so NA engine, powerkit etc.
07-01-2017, 11:11 AM
#28
On my car it sounds like flatulence and I find it deeply stupid and actually embarrassing when other people are present. I love the sound of the PSE. But the extended farting out the back (on my car it lasts 2-3 seconds) is ridiculous. What were they thinking -- hands-down the dumbest feature on the 991.
On early cars (I've owned many) with carburetors or MFI and no cats, you get the occasional crackle on decel, which is cool, because it's real. And it would be cool if Porsche simply replicated that phenomenon. But they had to make it cringe-inducingly fake. It's as dumb as installing a fake blow-off valve to make your Civic sound turbocharged.
On early cars (I've owned many) with carburetors or MFI and no cats, you get the occasional crackle on decel, which is cool, because it's real. And it would be cool if Porsche simply replicated that phenomenon. But they had to make it cringe-inducingly fake. It's as dumb as installing a fake blow-off valve to make your Civic sound turbocharged.
07-01-2017, 11:46 AM
#29
Burning Brakes
In this day and age, such a feature could easily be made user selectable through some sort of service mode that could be accessed by an owner. I could imagine being able to adjust the rpm and throttle opening where the exhaust valves opened and the second sound symposer activated. And I'd love to be able to calibrate my speedometer, not to mention resetting the service warning.
On a BMW 335i I previously, it was possible to calibrate the average fuel economy reading in the trip computer via the service mode. Sadly, the egregious speedometer error could not be ameliorated.
On a BMW 335i I previously, it was possible to calibrate the average fuel economy reading in the trip computer via the service mode. Sadly, the egregious speedometer error could not be ameliorated.
07-01-2017, 12:22 PM
#30
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Pretty soon we'll all be driving silent cars with electric propulsion. Until that time, anything that reminds me we're in the twilight of the golden age of the internal combustion engine is fine with me.