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992 has new/bigger turbos with more lag and 8 other facts!

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Old 12-30-2018, 08:45 PM
  #106  
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Originally Posted by groundhog
First off, the engine in the 992 has a higher compression ratio than the 991.2 and secondly the torque in the 992 S peaks at 530NM (relative to 550NM - 991.2 GTS) - the combination of these will be less feeling of lag (not that theres much when on the move and effectively none in S plus) and an even more linear feeling on the run up to 450HP. Look at the tqe/hp curves for the 991.2 GTS Vs 992 S.

On the nanny side of things - dangerous direction and far more consistent with the Carrera becoming a luxo GT cruiser, its certainly a Porker at nearly 1600kg.
But the engine has been depressurized. I am running at 18.1 psi in my 991.2 GTS versus 16 psi in the 992. It’s not the same feeling under launch or acceleration. The new engine has 443 hp, but it’s quite different power delivery with the extra gears. I also am not a fan of the faux exhaust outlets.
Old 12-30-2018, 10:46 PM
  #107  
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Originally Posted by GTS01


But the engine has been depressurized. I am running at 18.1 psi in my 991.2 GTS versus 16 psi in the 992. It’s not the same feeling under launch or acceleration. The new engine has 443 hp, but it’s quite different power delivery with the extra gears. I also am not a fan of the faux exhaust outlets.
Gears 7 and 8 are overdrive gears. Gears 1-6 are actually shorter. Top speed is hit in 6th gear.
Old 12-30-2018, 11:03 PM
  #108  
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Originally Posted by spdracerut
However, Porsche does not gear the Carrera so tall that it negates the torque advantage.
You still need to upshift at much lower RPM because power starts to drop after 6500RPM rather than 8250. So you inevitably make gearing taller by upshifting earlier because the rev range ends.

Originally Posted by spdracerut
So what's more impressive? 405 lb-ft of torque at 2150rpm with 500+hp at 6500rpm or 339 lb-ft of torque at 6000rpm and the same 500hp but at 8250rpm?
Just from these numbers, you can't really say, actually. You need to see the full curve to know. Knowing that you are talking about GT3 and GTS engines, I can tell that yes, GTS will probably have more area under the curve if you can get it to those numbers, but by a very tiny margin. Using peak power as a guideline for scaling (ideally, you'd take shift points, but I can't calculate optimal shift points for a hypothetical GTS tune), the GT3 engine converted from 8250RPM to 6500PRM equivalent would have 418lbs/ft at 4727 RPM, so even slightly higher equivalent torque. You do not need to have this exact reduction gear for this to conversion to be relevant - it works out that way more or less just through earlier shift points. So if it was not a GT3 engine but some hypothetical engine, in theory, it could have had more "area under the curve" in terms of effective torque to the ground. But knowing that GT3 engine has torque falling down pretty quickly at low revs, if we look at the entire curve starting from say 1500 RPM, the tuned GTS would have more.

But here is the rub - WHY would you be in this rev range ever if you care about performance? If you want to save the planet, stay under 2000. If you want to go fast, downshift (or let PDK do it automatically if that's too much work), and you end up above the peak torque area in either car. Some say "Oh you do not need to downshift if peak torque is at 2000RPM already" but that's not correct - if you get the same torque at 2000 and 4000 RPM, downshifting so that you rev up to 4000 rmp will give you twice as much power to the ground. So you need to downshift either way, if you want to go fast. So the curve below peak torque matters only to people who insist on buying a manual but don't know how to use it, really.

Originally Posted by spdracerut
It's obvious which one has more area under the power curve and therefore would be faster around a track.
Again, this is far from obvious with so many things in the mix. On a typical track, GT3 never goes below 5000RPM, so anything that's there is simply irrelevant. But then you get the issue of heat rejection - turbo engines need to expel more heat than NA engines of the same power (heat of compressing the air, heat from oil and coolant running through the turbo to cool it etc), but GTS has less cooling capacity than GT3. It will lose a lot of power when used more than a quarter mile at a time.

I tracked different 991.2 Turbo S extensively, both in stock form and modded to well over 700HP and with aftermarket intercoolers more than twice the size of what one can possibly fit into a GTS package and also down to 3400lbs in weight so not much heavier than GTS. Guess what - that torque monster on track is only slightly faster than a GT3. I tracked both Turbo S and GT3 extensively with data logging. And the culprit is heat. Intake temps go up, EAT goes up, intake air gets less dense robbing power, fuel mixture gets richer to save turbos robbing power, etc. It does not limp, like many other forced induction cars when driven hard (bravo Porsche), but it does gracefully degrade it's performance noticeably. It's unreasonable to expect GTS with smaller engine/turbos/rads/intercoolers/oil coolers not to degrade especially when tuned to 500HP+. I'm not bashing GTS engine - it's quite amazing, and I'd be happy with one. I just think it's just silly to compare torque at revs that are not that relevant for performance-focused driving and without correcting for gearing.

Anyway, take it for what it's worth. I'm not biased - I have both GT3 and a torque-monster modded Turbo S, and if I had to keep only one, I'd keep the Turbo S (need rear seats, and it's a better all-arounder in my opinion). But GT3 is better enough at the track that I keep it in addition to Turbo S just for that. The engine is a big part of its attraction. And I'm not tied to GT3 - it's actually for sale. I can get absolutely any mass-produced car in its place with just a click of a mouse, but I'll replace it with a GT3 RS, just because it's such a compelling package (the second choice was a coin toss between Perfomante and 600lt, so again, not biased against turbos in any way - turbo engines can be very good, especially if built from the outset for track/racing rather than for fuel economy reasons).
Old 12-30-2018, 11:43 PM
  #109  
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Originally Posted by Noah Fect
This analogy breaks down quickly in real life. Here in the US, I can attend any of a dozen different churches or none at all, or I can start a new one in my basement. And I can still vote for either Republicans or Democrats. Sure, we've always muttered under our breath that they're all the same bunch of crooks anyway, but recent events have demonstrated that this isn't in fact the case.

At the Porsche dealer I have no such option. It's turbos or nothing, at least for those of us who don't want a GT car.
You missed the point completely. I was referring to debating the general topic of NA vs FI. You are not going to convince someone who thinks FI is superior to NA and vice versa. It’s pointless.

But if the church of Porsche doesn’t have what you are looking for, you are completely free to explore other options that fit you better. Nobody is forcing you to be their products...
Old 12-31-2018, 03:17 AM
  #110  
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Originally Posted by MaxLTV
You still need to upshift at much lower RPM because power starts to drop after 6500RPM rather than 8250. So you inevitably make gearing taller by upshifting earlier because the rev range ends.



Just from these numbers, you can't really say, actually. You need to see the full curve to know. Knowing that you are talking about GT3 and GTS engines, I can tell that yes, GTS will probably have more area under the curve if you can get it to those numbers, but by a very tiny margin. Using peak power as a guideline for scaling (ideally, you'd take shift points, but I can't calculate optimal shift points for a hypothetical GTS tune), the GT3 engine converted from 8250RPM to 6500PRM equivalent would have 418lbs/ft at 4727 RPM, so even slightly higher equivalent torque. You do not need to have this exact reduction gear for this to conversion to be relevant - it works out that way more or less just through earlier shift points. So if it was not a GT3 engine but some hypothetical engine, in theory, it could have had more "area under the curve" in terms of effective torque to the ground. But knowing that GT3 engine has torque falling down pretty quickly at low revs, if we look at the entire curve starting from say 1500 RPM, the tuned GTS would have more.

But here is the rub - WHY would you be in this rev range ever if you care about performance? If you want to save the planet, stay under 2000. If you want to go fast, downshift (or let PDK do it automatically if that's too much work), and you end up above the peak torque area in either car. Some say "Oh you do not need to downshift if peak torque is at 2000RPM already" but that's not correct - if you get the same torque at 2000 and 4000 RPM, downshifting so that you rev up to 4000 rmp will give you twice as much power to the ground. So you need to downshift either way, if you want to go fast. So the curve below peak torque matters only to people who insist on buying a manual but don't know how to use it, really.


Again, this is far from obvious with so many things in the mix. On a typical track, GT3 never goes below 5000RPM, so anything that's there is simply irrelevant. But then you get the issue of heat rejection - turbo engines need to expel more heat than NA engines of the same power (heat of compressing the air, heat from oil and coolant running through the turbo to cool it etc), but GTS has less cooling capacity than GT3. It will lose a lot of power when used more than a quarter mile at a time.

I tracked different 991.2 Turbo S extensively, both in stock form and modded to well over 700HP and with aftermarket intercoolers more than twice the size of what one can possibly fit into a GTS package and also down to 3400lbs in weight so not much heavier than GTS. Guess what - that torque monster on track is only slightly faster than a GT3. I tracked both Turbo S and GT3 extensively with data logging. And the culprit is heat. Intake temps go up, EAT goes up, intake air gets less dense robbing power, fuel mixture gets richer to save turbos robbing power, etc. It does not limp, like many other forced induction cars when driven hard (bravo Porsche), but it does gracefully degrade it's performance noticeably. It's unreasonable to expect GTS with smaller engine/turbos/rads/intercoolers/oil coolers not to degrade especially when tuned to 500HP+. I'm not bashing GTS engine - it's quite amazing, and I'd be happy with one. I just think it's just silly to compare torque at revs that are not that relevant for performance-focused driving and without correcting for gearing.

Anyway, take it for what it's worth. I'm not biased - I have both GT3 and a torque-monster modded Turbo S, and if I had to keep only one, I'd keep the Turbo S (need rear seats, and it's a better all-arounder in my opinion). But GT3 is better enough at the track that I keep it in addition to Turbo S just for that. The engine is a big part of its attraction. And I'm not tied to GT3 - it's actually for sale. I can get absolutely any mass-produced car in its place with just a click of a mouse, but I'll replace it with a GT3 RS, just because it's such a compelling package (the second choice was a coin toss between Perfomante and 600lt, so again, not biased against turbos in any way - turbo engines can be very good, especially if built from the outset for track/racing rather than for fuel economy reasons).
very helpful stats and real world usage. This what people don’t understand when they look at simple torque figures and 0-60 times. Otherwise, why would a 991.2 GT3 have a better Ring time than a 991 Turbo!
Old 12-31-2018, 05:11 AM
  #111  
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Originally Posted by GTS01
But the engine has been depressurized. I am running at 18.1 psi in my 991.2 GTS versus 16 psi in the 992. It’s not the same feeling under launch or acceleration. The new engine has 443 hp, but it’s quite different power delivery with the extra gears. I also am not a fan of the faux exhaust outlets.
The higher static compression ratio means the engine will develop more torque early in the rev range (as the compression ratio is higher) and the absolute compression ratio will be defined by the boost level and elevation.

10.0 static at 1000 ft with 18PSI = 22:1 (actual compression ratio)
10.5 static at 1000 ft with 16PSI = 21.75:1 (actual compression ratio)

Couple this with shorter gearing, higher static compression ratio and lower boost (for the same result) = sharper throttle response and less apparent lag.




Old 12-31-2018, 01:21 PM
  #112  
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Originally Posted by MaxLTV
You still need to upshift at much lower RPM because power starts to drop after 6500RPM rather than 8250. So you inevitably make gearing taller by upshifting earlier because the rev range ends.



Just from these numbers, you can't really say, actually. You need to see the full curve to know. Knowing that you are talking about GT3 and GTS engines, I can tell that yes, GTS will probably have more area under the curve if you can get it to those numbers, but by a very tiny margin. Using peak power as a guideline for scaling (ideally, you'd take shift points, but I can't calculate optimal shift points for a hypothetical GTS tune), the GT3 engine converted from 8250RPM to 6500PRM equivalent would have 418lbs/ft at 4727 RPM, so even slightly higher equivalent torque. You do not need to have this exact reduction gear for this to conversion to be relevant - it works out that way more or less just through earlier shift points. So if it was not a GT3 engine but some hypothetical engine, in theory, it could have had more "area under the curve" in terms of effective torque to the ground. But knowing that GT3 engine has torque falling down pretty quickly at low revs, if we look at the entire curve starting from say 1500 RPM, the tuned GTS would have more.

But here is the rub - WHY would you be in this rev range ever if you care about performance? If you want to save the planet, stay under 2000. If you want to go fast, downshift (or let PDK do it automatically if that's too much work), and you end up above the peak torque area in either car. Some say "Oh you do not need to downshift if peak torque is at 2000RPM already" but that's not correct - if you get the same torque at 2000 and 4000 RPM, downshifting so that you rev up to 4000 rmp will give you twice as much power to the ground. So you need to downshift either way, if you want to go fast. So the curve below peak torque matters only to people who insist on buying a manual but don't know how to use it, really.


Again, this is far from obvious with so many things in the mix. On a typical track, GT3 never goes below 5000RPM, so anything that's there is simply irrelevant. But then you get the issue of heat rejection - turbo engines need to expel more heat than NA engines of the same power (heat of compressing the air, heat from oil and coolant running through the turbo to cool it etc), but GTS has less cooling capacity than GT3. It will lose a lot of power when used more than a quarter mile at a time.

I tracked different 991.2 Turbo S extensively, both in stock form and modded to well over 700HP and with aftermarket intercoolers more than twice the size of what one can possibly fit into a GTS package and also down to 3400lbs in weight so not much heavier than GTS. Guess what - that torque monster on track is only slightly faster than a GT3. I tracked both Turbo S and GT3 extensively with data logging. And the culprit is heat. Intake temps go up, EAT goes up, intake air gets less dense robbing power, fuel mixture gets richer to save turbos robbing power, etc. It does not limp, like many other forced induction cars when driven hard (bravo Porsche), but it does gracefully degrade it's performance noticeably. It's unreasonable to expect GTS with smaller engine/turbos/rads/intercoolers/oil coolers not to degrade especially when tuned to 500HP+. I'm not bashing GTS engine - it's quite amazing, and I'd be happy with one. I just think it's just silly to compare torque at revs that are not that relevant for performance-focused driving and without correcting for gearing.

Anyway, take it for what it's worth. I'm not biased - I have both GT3 and a torque-monster modded Turbo S, and if I had to keep only one, I'd keep the Turbo S (need rear seats, and it's a better all-arounder in my opinion). But GT3 is better enough at the track that I keep it in addition to Turbo S just for that. The engine is a big part of its attraction. And I'm not tied to GT3 - it's actually for sale. I can get absolutely any mass-produced car in its place with just a click of a mouse, but I'll replace it with a GT3 RS, just because it's such a compelling package (the second choice was a coin toss between Perfomante and 600lt, so again, not biased against turbos in any way - turbo engines can be very good, especially if built from the outset for track/racing rather than for fuel economy reasons).
Very interesting post and a good read.
Old 12-31-2018, 04:56 PM
  #113  
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Originally Posted by groundhog
The higher static compression ratio means the engine will develop more torque early in the rev range (as the compression ratio is higher) and the absolute compression ratio will be defined by the boost level and elevation.

10.0 static at 1000 ft with 18PSI = 22:1 (actual compression ratio)
10.5 static at 1000 ft with 16PSI = 21.75:1 (actual compression ratio)

Couple this with shorter gearing, higher static compression ratio and lower boost (for the same result) = sharper throttle response and less apparent lag.
read the article. There will be more lag.
Old 12-31-2018, 06:58 PM
  #114  
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Originally Posted by garfunkle
The NA cars get better economy when you actually drive them. The 3.0tt only wins when you don't get into boost. Like that test with an M3 against a Prius and the M3 got better economy for hot laps. No 24 hour Porsches use turbos. The RSR cars are mid engine - yes. But we were talking performance of things that existed and how is that relevant when I brought up dyne curves of other things and the response was - " well, we're only considering 3.8NA vs 3.0tt"?
The RSR only went mid engine because the rear engine weight bias ate its tires too quickly.

In a sprint, a rear engine car has the advantage of corner exit traction. More gas, more grip.

Just ask the 935. A few of those could outrun F1 cars. With a windshield, a body, and doors.
Old 12-31-2018, 07:05 PM
  #115  
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Originally Posted by garfunkle

read the article. There will be more lag.
I did read the article and pointed out why it was misleading - that's why it's important to look at other factors in terms of overall response

Last edited by groundhog; 12-31-2018 at 10:39 PM.
Old 12-31-2018, 07:43 PM
  #116  
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Originally Posted by MaxLTV
But all that torque goes through taller gearing to adjust for lower effective rev range, and that cancels out pretty much all of the "advantage". Torque in general is a misleading metric invented by some auto manufacturers' marketing departments to sell low-tech engines back in the day. "So what if it only makes 150HP out of freaking 6 liters - it has torque!" In reality, "torque" is like a diameter of a glass with a pint of beer - if there is still one pint in a glass (total HP), the width of a glass does not matter all that much. Put a 1/2 reduction gear on a 9000RPM peak HP engine with 300lb/ft at 3500, and you have yourself a 4500RPM peak HP engine with torque of 600lbs/ft at 1750RPM - does the latter look more impressive? It should not because it's the same engine, I swear with my hand on a physics textbook :-). But some people go "holy crap, it's 600lbs at 1750RPM, you can't argue with that" - just hilarious.

Anyway, I'm not making the point that turbo engines are not good - they can be made virtually lag-free, and I love them, although not as much as electric motors or naturally aspirated engines. Just wanted to point out that torque fetish is not grounded in reality.
Max - look at the WHP curves for the GTS and GT3​​​​​​. The gearing isn't particularly long in the GTS but it isn't as short as the gearing in the GT3. As with most performance cars the gearing has to fit the torque profile and the nominal redline.



Gears are torque multipliers and ultimately define the force at the contact patch which propels the car forward - the rate at which it does this is ultimately controlled by the amount of HP developed by the engine.

Keep in mind there are plenty of performance cars out there with much lower redlines than the GT3 which perform as well if not better for example the Viper.

The GTS I used last season never went below 3500 RPM on track (sports plus) - thus revving over a range of 4000 RPM. This uses the torque and gearing to full effect. Likewise the GT3 has an effective working range of about 4000 RPM, the difference being it has to rev higher to make power due to the torque limitations of a 6 cyl NA engine with a static compression ratio.

Simply a different way to skin the cat. The GT3s advantage is really developed through its shorter gearing. Where in third and fourth, the go to gears, it puts down about 1%-5% more force at the contact patch than the GTS. Even then on track, on the same tires they are close, so close that the difference in timed performance is down to the driver.

Interesting note - the GT2 RS has the same primary gears as the the S and GTS - with exception of 7th and the final reduction which is 3.96. If Porsche put this diff in the GTS it would generate 8% more force at the contact patch than the GT3 in third - this would be one smart way to improve the performance of the GTS without impacting on the engine performance and longevity).

Also, I live in a hot clime and I can't find any evidence of pulled timing in any of the events I took part in last year.



Last edited by groundhog; 01-01-2019 at 10:02 AM.
Old 01-01-2019, 10:09 AM
  #117  
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Holy smokes . . . I see the insecure, been a Porsche owner for 5 minutes need to get a life (just how does STG accumulate so many posts in that short period of time) brigade are now crashing a performance/technology thread as well . . .

Seems like a lot of newcomers to Porsche with absolutely no real world experience with 911 turbos, performance 911s and very little experience with 911s in general are getting all worked up over nothing. Ignorance, fear, pride???????? what drives this???????

Porsche does turbos right. Anyone complaining about lag in the new 911s either does not have any car control and driving skill or zero real world experience driving Porsche performance cars. A 991.1 S/4S is not a performance car (there are sedans with comparable numbers). . .

Lol, at all this silliness about thinking the 992 programming is going to somehow make your car slower or make you conform to speed limits. Those here complaining about that silliness likely cannot even drive a 911 at 7/10s on a consistent basis in the first place . . . The 992 is not going to magically put anyone in wimp mode when they are trying to have fun . . .

Here is a thought, step away from the computers and stop spending day in and day out, literally weeks, complaining about a car you have not driven and likely won't drive . . . some here don't even have a 911s . . . Get out and enjoy what you have, stop feeling insecure about it and step down to the dealer and drive a 992 when they hit your local lot so you at least sound a bit intelligent/informed.

Better yet, step away from the computer, go to a driving school and learn how to drive and enjoy a 911 and I bet your posts count and generally negativity will decrease ramatically.
Old 01-01-2019, 12:39 PM
  #118  
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Originally Posted by Bob Z.
I could live with the all of the new stuff in the 992 if it looked better than the 991.2.
Amen brother. To my eyes it’s UGLY. Panacarerra.
Old 01-01-2019, 12:55 PM
  #119  
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I drove the BGB tuned 991.2 GTS. It was excellent. As fun as my 997.1 Turbo.

Id have no problem driving a 992 Carrera S with the same upgrades. I wouldnt see the need for a 992 Trubo in my driveway.
Old 01-02-2019, 12:00 AM
  #120  
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Originally Posted by Argon_
The RSR only went mid engine because the rear engine weight bias ate its tires too quickly.
They also went mid-engine to improve the aerodynamics of the car by being able to fit a proper rear diffuser. Mid-engine also reduced the polar inertia of the car making it handle better.

https://www.roadandtrack.com/motorsp...rank-walliser/



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