991.2 vs 992
Burning Brakes
Joined: Jan 2015
Posts: 834
Likes: 64
From: El Dorado Hills, CA
Yeah those old turbos were a handful with the lag then huge power surge, or so I have heard. Never driven one, and no desire to. I would probably get myself in trouble in short order.
Pro
Joined: Mar 2017
Posts: 607
Likes: 282
From: Bay Area, CA
The best way I can describe the two is that the 991.2 is a better car but the 991.1 is the better 911. I think Porsche will sort out the turbos in the new 992's and may be even before that in the 2018 or 2019 991.2's. But for now, the 991.1 is definitely the more responsive car when it comes to the motor.
Rennlist Member
Joined: Aug 2012
Posts: 8,246
Likes: 2,691
From: Pac NW
Burning Brakes
Joined: Feb 2017
Posts: 1,219
Likes: 138
From: Golden, CO
On the 991.2, when you floor the throttle, you initially get less torque than the 991.1, due to the turbo engine's reduced displacement and compression ratio, and then it takes ten times as long for the turbos to spool up before the engine generates its max.
That difference between a quarter of a second and 2-3 seconds is turbo lag.
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Burning Brakes
Joined: Feb 2017
Posts: 1,219
Likes: 138
From: Golden, CO
Porsche publishes power and torque curves for the 991.2 starting at 1250 rpm. Do you that the company did that because they didn't want anyone employing such rpm?
Rennlist Member
Joined: Aug 2012
Posts: 8,246
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From: Pac NW
I like my connecting rods right where they are, thanks.
The old-school rule was always "No floorboarding the car below 1/3 redline." Nowadays I can see extending that guideline to redline/4, maybe... but no lower.
The old-school rule was always "No floorboarding the car below 1/3 redline." Nowadays I can see extending that guideline to redline/4, maybe... but no lower.
Banned
Joined: Jun 2016
Posts: 1,350
Likes: 13
From: Australia
If you drive in the correct gears there is no discernible lag - if you drive in 7th gear at low revs you can prove there is lag (or any lugging gear), because all turbos have some level of lag. The only place you find it being endlessly debated is on the internet, seriously its non-issue 
The engine response is just as good as that found in the 488GTB.
The engine response is just as good as that found in the 488GTB.
Drifting
Joined: Jul 2007
Posts: 3,492
Likes: 1,230
From: Canada
Actually, it would. While a 991.1 can produce less maximum torque at 1500 rpm than a 991.2, if you floor the throttle, it delivers what it has in a quarter of a second or so.
On the 991.2, when you floor the throttle, you initially get less torque than the 991.1, due to the turbo engine's reduced displacement and compression ratio, and then it takes ten times as long for the turbos to spool up before the engine generates its max.
That difference between a quarter of a second and 2-3 seconds is turbo lag.
On the 991.2, when you floor the throttle, you initially get less torque than the 991.1, due to the turbo engine's reduced displacement and compression ratio, and then it takes ten times as long for the turbos to spool up before the engine generates its max.
That difference between a quarter of a second and 2-3 seconds is turbo lag.
Not really a real world test anyway because who would ever step on the gas at 1,500 rpm in 7th gear anyway.
If you drive both cars you'll find that the NA engine is more entertaining from 4,000 - 5,500 RPM, but below that the tiny lag penalty of the 991.2 engine is almost unnoticeable and by comparison a much better engine for everyday driving.
Burning Brakes
Joined: Feb 2017
Posts: 1,219
Likes: 138
From: Golden, CO
I'm sorry but I don't agree. The NA engine doesn't make anywhere near the torque the 99.2 engines do at 1,500 RPM and the time difference between 1,500RPM and 4,000 RPM where the torque and HP come alive is much greater than the .5sec of lag you'd feel in the 991.2.
Not really a real world test anyway because who would ever step on the gas at 1,500 rpm in 7th gear anyway.
If you drive both cars you'll find that the NA engine is more entertaining from 4,000 - 5,500 RPM, but below that the tiny lag penalty of the 991.2 engine is almost unnoticeable and by comparison a much better engine for everyday driving.
Not really a real world test anyway because who would ever step on the gas at 1,500 rpm in 7th gear anyway.
If you drive both cars you'll find that the NA engine is more entertaining from 4,000 - 5,500 RPM, but below that the tiny lag penalty of the 991.2 engine is almost unnoticeable and by comparison a much better engine for everyday driving.
Clearly, the 991.2 has virtually no turbo lag at 4000 rpm+ and considerable turbo lag below 2000 rpm. And while you might consider flooring the throttle below 2000 rpm in top gear to be absurd, I again point out that Porsche publishes a full-power output curve for the engine starting at 1250 rpm.
Moreover, since the turbo wastegates on the 991.2 are computer controlled, if Porsche felt that producing full power at low rpm was harmful to the engine, it would be an easy matter to limit boost until whatever rpm was determined to be safe for full boost. You might ponder the fact that Porsche has not done this at all.
Perhaps I'm an outlier here, but when I'm driving in my 991.2 in town, with low speed limits, traffic, and no opportunity to go quickly, I don't spin my engine at 5000 rpm just to make noise and wear it out more quickly. And I have been known to floor the throttle at considerably less than 1500 rpm if I need a little acceleration and will downshift if I want a lot of acceleration.
My previous car, BMW 335i with manual transmission, was subjected to full throttle at as little as 1000 rpm in sixth gear for some 50,000 miles and showed no ill effects.
Of course, the beauty of a manual transmission is that you can drive your car your way and I can do the same with mine.