STG

Anytime. Sorry to have upset you. I hope you figure it out. Good luck

Jenner

I realize this thread is about tuning out the pops and burbles on the 991.1 but I just wanted to clear up this info on the 991.2 Sport Plus mode

Not plausible or a possibility. It's a fact. The 991.2 Sport Plus mode is different than prior NA engine models as JR pointed out.

Try lifting off in Sport Plus and coasting. You will see it build up to 2 PSI of positive turbo pressure AND you will hear the air going through the engine. It sounds very different on coast down than Sport. The throttle body is kept open, and they shut off fuel and spark, so the engine acts like an air pump just sucking in air and exhausting it, keeping the turbos spinning. This also happens when you reduce throttle, not just a full lift, so that the turbos are right there ready when you request more.

In just sport mode I HAVE seen it build 1 PSI in coast down, but it takes much longer than Sport Plus, which does it almost instantly. Also during coast down Sport pops and bangs and then goes nearly silent, where Sport Plus actually has some nice exhaust tone due to this anti-lag feature keeping the turbos spooled.

Exactly right:
"The most important new feature comes in the form of an anti-lag system that brings the all-important instant response.

As opposed to the aggressive, turbocharger-consuming setup seen on rally cars, Porsche engineers went for a milder approach, basically turning the engine into an air pump during the overrun phase.

Take your foot off the gas and air will continue to flow into the cylinders. Since the air is compressed by the cylinders, this maintains the turbo's spinning state, thus minimizing lag.

Since the system's effect is more noticeable on the Sport and [most noticeable] Sport Plus driving modes, your 911 won't deliver unexpected boost surprises during busy traffic moments."

"To minimize lag, the mono-scroll, fixed-vane turbochargers use a vacuum-operated wastegate system to manage charge pressure. Additionally, whether at full throttle or completely off the gas, air is flowing to the turbos to help them spin. More importantly, the compressors do not need to build up a very high pressure.

JR956678

Fascinating post Jenner and thanks for sharing the information. As you note, I guessed they were doing things with the 991.2 because of my observations of my own car. I can pretty easily see how shutting off spark and fuel and holding the hrottle body open on overrun would have a side effect of reducing pops and burbles though it sounds like the real intent was to keep the turbos spinning.

John@Fabspeed

Very educated/impressive replies Jenner

NoGaBiker

So "facts" are not plausible? Hmmm... I think we have different understandings of what this word means.

Jenner

Plausible
superficially fair, reasonable, or valuable but often specious

Fact
a thing that is indisputably the case.

It's more than reasonable or probable...its 100% true/correct.

The 991.1 and 991.2 Sport Plus modes are totally different.
No pops, bangs, etc on throttle lift on the 991.2 Sport Plus mode. No turbos to keep spooled on the 991.1.

NoGaBiker

I'm sorry but I have to believe you added the bolded on your own. Either that or you spent a long time searching for some deadbeat dictionary that added that clause.

"Possible" is the word that conveys the "often specious" implication.

Me in October: I bet Mr. Trump will be President in January.
Reasonable person: Well... that's possible.
Unreasonable person: Yeah.. that's plausible.

plau·si·ble
ˈplôzəb(ə)l/
adjective
(of an argument or statement) seeming reasonable or probable.
"a plausible explanation"
synonyms: credible, reasonable, believable, likely, feasible, tenable, possible, conceivable, imaginable; More

Jenner

I spent a few seconds on google...so can you:
http://lmgtfy.com/?q=plausible+merri...ter+dictionary

Bold is usually used for emphasis and of course I added it on my own, how else would it get there?

Not sure what your issue is. You didn't know what you were talking about as you were speaking only from your experience with the 991.1. I backed up what JD already said and quoted what's really going on with the 991.2.

You said it "doesn't make any sense" to you. I made sense of it for you and anyone else who might wonder why Sport Plus behaves differently than you might expect.

squid42

Regardless of the argument here...

... I think it is certain that you could have the vent open with reduced burble and farts on either model. I described a method to finding out many pages ago. It should be tried by somebody who rates this as important.

planet

Evidence that on the 991.2, Sport mode has the most popping and gurgling by far:


I'm interested in playing with the mix/match options on Individual, as well.

Noah Fect

Regardless of who's right about turbo behavior in various modes, adding a connotation of speciousness to the primary definition of "plausible" is just plain wrong. It cannot possibly be justified by a survey of English usage.

Not every day you find a bug in the dictionary, especially not M-W, but that's a legitimate one.

Code

Nice vid. The difference is clear. Thanks for posting.

Gary JR

nah dictionary is right - by definition

If I hear correctly Sport is the only setting with any gurgling.

NoGaBiker

My issue is with your mischaracterization of the word "plausible." I neither know nor care anything about the performance of the 991.2. You must be confusing me with somebody in this thread who is arguing with you about that.

I pointed out way back that somebody's description of pops and burbles didn't match my experience, said perhaps that was a 991.2 thing, he explained how it was a 991.2 thing and why he thought (or theorized, if you will) that was the case, and I said that theory sounded plausible. Which means likely, believable, reasonable. Not absolutely true, but nothing about it casts doubt on the theory. Had I said it sounded "possible", that would have implied I was allowing the physical possibility he could be right, but I didn't find it likely that was the case.

Plausible implies a "wide gap" of likelihood, where possible implies a narrow gap; plausible implies that I'd be surprised if you're wrong, where possible implies I'd be surprised if you're right.

You came along and apparently (I didn't read your explanation; like I said, I don't have any interest in the 991.2 right now) "proved" that what I said was plausible was in fact the case. So you merely affirmed my comment. Meaning we are on the same page. So when you began your response to my comments with "No", I realized you had a fundamental misunderstanding of the word "plausible." So all this time I've simply been performing a PSA for you on the word. No need to thank me -- being right is all the thanks I need.

Jenner

Wow...I dropped it yesterday, thought you did too. You need to get over yourself! Don't pull a muscle patting yourself on the back

We are all Porsche fans here. Even if we don't agree....have a good one. I'm done with this topic.