991.2 9A2 engine vs 9A1 technical analysis
09-13-2015, 02:53 PM
#31
Rennlist Member
If you are driving the car at +5000rpms, like you would with 9A1 engine under spirited condition, the turbo lag will be virtually nonexistent. Test it out yourself with any modern performance turbocharged engine, if you don't believe me... In all honesty, the drive-by-wire throttle in these modern cars will probably cause more throttle lag...
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Bulldawgfan1000 (09-24-2021)
09-13-2015, 03:04 PM
#32
Nordschleife Master
As it is often the case of these online "technical discussion", one is confusing boost threshold with actual turbo lag. As it is stated in the C&D article, lags are only noticeable if you are lugging the engine at low rpms, where the engine doesn't generate enough exhaust gas volume to spool up the turbine quickly enough. So your own conclusion isn't correct.
If you are driving the car at +5000rpms, like you would with 9A1 engine under spirited condition, the turbo lag will be virtually nonexistent. Test it out yourself with any modern performance turbocharged engine, if you don't believe me...
If you are driving the car at +5000rpms, like you would with 9A1 engine under spirited condition, the turbo lag will be virtually nonexistent. Test it out yourself with any modern performance turbocharged engine, if you don't believe me...
2000 RPM is not really lugging the engine, is it? So here I am driving behind a slow poke at a reasonable 2000RPM in 5th gear at 60MPH (or thereabouts), find an opportunity to pass but I have to take it quickly... and I am confronted with a full 2 sec turbo lag... is that OK?
09-13-2015, 03:05 PM
#33
Rennlist Member
Thread Starter
As it is often the case of these online "technical discussion", one is confusing boost threshold with actual turbo lag. As it is stated in the C&D article, lags are only noticeable if you are lugging the engine at low rpms, where the engine doesn't generate enough exhaust gas volume to spool up the turbine quickly enough. So your own conclusion isn't correct.
If you are driving the car at +5000rpms, like you would with 9A1 engine under spirited condition, the turbo lag will be virtually nonexistent. Test it out yourself with any modern performance turbocharged engine, if you don't believe me... In all honesty, the drive-by-wire throttle in these modern cars will probably cause more throttle lag...
If you are driving the car at +5000rpms, like you would with 9A1 engine under spirited condition, the turbo lag will be virtually nonexistent. Test it out yourself with any modern performance turbocharged engine, if you don't believe me... In all honesty, the drive-by-wire throttle in these modern cars will probably cause more throttle lag...
Read here:
https://rennlist.com/forums/991-gt3/...l#post12574787
09-13-2015, 03:07 PM
#34
Drifting
As it is often the case of these online "technical discussion", one is confusing boost threshold with actual turbo lag. As it is stated in the C&D article, lags are only noticeable if you are lugging the engine at low rpms, where the engine doesn't generate enough exhaust gas volume to spool up the turbine quickly enough. So your own conclusion isn't correct.
If you are driving the car at +5000rpms, like you would with 9A1 engine under spirited condition, the turbo lag will be virtually nonexistent. Test it out yourself with any modern performance turbocharged engine, if you don't believe me... In all honesty, the drive-by-wire throttle in these modern cars will probably cause more throttle lag...
If you are driving the car at +5000rpms, like you would with 9A1 engine under spirited condition, the turbo lag will be virtually nonexistent. Test it out yourself with any modern performance turbocharged engine, if you don't believe me... In all honesty, the drive-by-wire throttle in these modern cars will probably cause more throttle lag...
Last edited by GSIRM3; 09-13-2015 at 04:15 PM.
09-13-2015, 03:21 PM
#35
Rennlist Member
Quote from the C&D article: "... Under intense questioning, one of the Porsche engineers admitted that at 1800 rpm, the engine needs three full seconds to produce full torque from a closed throttle. Though he was quick to add that the turbo lag dropped to two seconds at 2000 rpm and only one second at 2300. "
2000 RPM is not really lugging the engine, is it? So here I am driving behind a slow poke at a reasonable 2000RPM in 5th gear at 60MPH (or thereabouts), find an opportunity to pass but I have to take it quickly... and I am confronted with a full 2 sec turbo lag... is that OK?
2000 RPM is not really lugging the engine, is it? So here I am driving behind a slow poke at a reasonable 2000RPM in 5th gear at 60MPH (or thereabouts), find an opportunity to pass but I have to take it quickly... and I am confronted with a full 2 sec turbo lag... is that OK?
Also, your article makes no mentioning of the tire used in the Turbo, which I expect is just the stock P-zero comparing to the stock Sport Cup 2 on the GT3. That will no doubt heavily undermine the chassis response and ability to put down the power on the Turbo. This is again which is why I take these reviews with a grain of salt.
Have a look at the recent EVO lap video of GT3RS and that of Turbo S from a few months ago at the track, GT3RS is noticeably harder to drive despite its NA engine and lack of so called turbo lags and non-linear power delivery. They both put down the same laptime despite the huge tire and weight advantage that RS enjoys over the Turbo S.
All in all, I can't change biased opinion over the internet. But hopefully, someone with a more open mind and some decent technical understanding will find my posts useful and refreshing to read in this sea of non-sense.
09-13-2015, 03:32 PM
#36
Rennlist Member
Why don't you just go and test drive a M4 yourself? Or better yet, wait for the 991.2 to arrive next year and try it out yourself. Not sure how exactly you expect me to "duplicate" when these cars aren't even being sold yet.
Or maybe, just enjoy your current car as it is, instead of spending so much time on discussing cars that doesn't even interest you nor plan to own...
Or maybe, just enjoy your current car as it is, instead of spending so much time on discussing cars that doesn't even interest you nor plan to own...
09-13-2015, 03:37 PM
#37
Nordschleife Master
But... I agree with you that these engines love to rev and many of us run them at higher regimes. And there lies the irony of turbocharging gas savings when the engine is run at high revs.
09-13-2015, 03:41 PM
#38
Rennlist Member
I beg to differ that 2k RPM is an improper range for typical highway driving. For most of us to get to the good driving bits we need to drive highway miles with heavy traffic and you do not do that at 5k RPM.
But... I agree with you that these engines love to rev and many of us run them at higher regimes. And there lies the irony of turbocharging gas savings when the engine is run at high revs.
But... I agree with you that these engines love to rev and many of us run them at higher regimes. And there lies the irony of turbocharging gas savings when the engine is run at high revs.
09-13-2015, 03:44 PM
#39
Nordschleife Master
There you go. Porsche pretty much done the impossible, lowering the emission and while preserving the top end response of their flat-six. I don't know what else you could ask for with the exceptions of hybrid technology and perhaps electric turbo (or supercharger to be technically correct) that will remove any sort of lag all together. But I don't think the cost and reliability of those things are ready until the next gen 992.
09-13-2015, 03:47 PM
#40
Rennlist Member
To sum it down...
More power requires more consumption, there is no magic in that. But at your average cruising speed and with a sane and legal driving style, these engines will be no doubt more efficient than the last gen. But if you are doing triple digit on the highway, (lol hope you got a decent radar detector and the Waze app opened) and going full throttle to pass every car you see. Well, you should expect anything other than terrible gas mileage. It is the same thing as you would still get low 20mpg when you drive the **** out of a Pruis that rated for +40-50mpg.
Don't really see the irony in that
09-13-2015, 03:50 PM
#41
Race Director
991.2 9A2 engine vs 9A1 technical analysis
Originally Posted by ADias
I guess you do not see the irony of the lack of gas savings (in real world terms) of the whole turbocharging movement.
Back to square one ....
09-13-2015, 03:54 PM
#42
Rennlist Member
Thread Starter
Nothing to do with tires, gt3 vs turbo, etc. Turbo vs NA.
We get it, you like your turbo. But for many of us turbos do have a downside. Which is why many future GT cars will stick with normal aspiration. You can minimize lag, you can say it doesn't bother you, but it does exist.
09-13-2015, 04:04 PM
#43
Rennlist Member
No, what I'm saying is that even the best turbo engines in the world, of which the 991 turbo is one, have lag. And that lag, even properly driven, has a cost. Normal aspiration vs turbo that cost was 2 feet on that day, as measured by one of the best drivers in the world.
Nothing to do with tires, gt3 vs turbo, etc. Turbo vs NA.
We get it, you like your turbo. But for many of us turbos do have a downside. Which is why many future GT cars will stick with normal aspiration. You can minimize lag, you can say it doesn't bother you, but it does exist.
Nothing to do with tires, gt3 vs turbo, etc. Turbo vs NA.
We get it, you like your turbo. But for many of us turbos do have a downside. Which is why many future GT cars will stick with normal aspiration. You can minimize lag, you can say it doesn't bother you, but it does exist.
Each engine configuration has its trade off, there is no doubt about that. But for a modern +3000lbs sports car that I can fit an adult passenger andtwo kids and still be able to drive to the grocery store, my personal opinion, for whatever that is worth, is that it benefits more from than increase in power than the marginal increase in throttle response.
For those, who haven't made up their mind. I suggest have a look of these two videos. Both cars costs the same roughly (assuming you can still get a RS), it is really just a pick between a focused weekend track toy and DD that you can enjoy in any situation. I personally go for the more usable Turbo that I can enjoy everywhere I go.
09-13-2015, 04:14 PM
#44
Race Director
No, what I'm saying is that even the best turbo engines in the world, of which the 991 turbo is one, have lag. And that lag, even properly driven, has a cost. Normal aspiration vs turbo that cost was 2 feet on that day, as measured by one of the best drivers in the world.
Nothing to do with tires, gt3 vs turbo, etc. Turbo vs NA.
We get it, you like your turbo. But for many of us turbos do have a downside. Which is why many future GT cars will stick with normal aspiration. You can minimize lag, you can say it doesn't bother you, but it does exist.
Nothing to do with tires, gt3 vs turbo, etc. Turbo vs NA.
We get it, you like your turbo. But for many of us turbos do have a downside. Which is why many future GT cars will stick with normal aspiration. You can minimize lag, you can say it doesn't bother you, but it does exist.
09-13-2015, 04:18 PM
#45
Rennlist Member
Thread Starter