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991.2 GT3 vs 992 GT3 Turbo?

Macca

Its all about the torque with these new engines. There are now tuned 991.2 Base Carreras making an easy 485bhp with 455lbft torque. Add Cup2, lowering springs, track alignment, pads and fluid and on the track you can really see that torque working. After all they only weight 30-40kg more than a GT4. The next GT3 if turbocharged wont need to be more than 520bhp to be 1-2s per minute lap quicker than the outgoing 991.2 GT3, the extra 95lbft torque it will ship with (432lbft is my guess - the 992 engines seem torque limited to 404lbft just like the current 991.2 GTS) will be enough on the track with revised suspension and tyres to blow the older cars into the weeds. As it has always been. And life goes on. managing the increased weight will be their prime challenge as the turbo engine is likely to come in 20kg heavier.

My money is on the next GT4 being 390bhp (395PS) with 332lbft turbo 4 as per the chart. Porsche invented the GT4 platform out of the box, I dont think they have any heritage or rules they have t follow on this car....

Argon_

If I wanted to build a track beast, I'd start out by swapping bigger turbos. Shift the torque peak higher up and enable a rev limit increase; small turbos, like the stock ones will run out of puff in the high revs.

Macca

Yes. Where the smaller turbo in the base 991.2 Carrera helps is that spools up qicker and at lower rpm reducing some of the additional lag inherent in the larger turbo applications (such as GTS which I test drove a while before deciding on base Carrera). This is great for road applications but the downside as you have suggested is they run out of puff higher in the rev range.

If Porsche do install a blown engine in the GT3/RS I suspect it will have a larger turbo and a 8000rpm rev limit moving the power up the curve as you suggest. For the track you are always at minimum 2500 rpm so spool latency at that rpm is not as bit a factor. Who knows they may even implement electric 48v turbo to fill the latency from 0 rpm. that would address much of the shortcomings of the turbo application...

Argon_

Who needs that when you can have ANTILAG.

But really, I find the pattern of torque-power-dead (small turbo) to be much less fun and engaging than the medium to large turbo figure. The perception of an engine dying in its last 1500 revs just feels wrong. This happens whenever you try and overboost a tiny turbo, like the aforementioned tuned base cars. A bigger turbo also stresses an engine less, paradoxically, assuming the same level of boost; this is due to reduced backpressure, and peak torque at a higher RPM.

So go bigger on the turbos, and just keep the revs up, like you would with a peaky N/A motor...

Macca

My recent turbo experience suggests the opposite. Maybe its just a personal thing. For road and street driving the latency of the larger turbo installations annoys me and Im rarely anywhere near redline when I shift, even pushing hard on a back road. Partly as these modern cars in 3rd and 4th gear will put you into double the speed limit to hit the limiter. Even in 3.5 years of 991.1 GT3 ownership I found myself disappointingly rarely above 8000 rpm when road driving. On the track however I would shift at 9000 rpm 5 times in a typical lap!

I have just gone through a tuning program with my renault megane RS275. This is a well known platform and I followed the RSR Nurburgring car development programme which is pretty typical as these cars are very popular on European tracks. There seems always a compromise when upgrading turbos and intercoolers and such like. Im my case increasing the intercooler size by 65% increased latency at low throttle inputs considerably (static intake pressure at idle when from -400mbar to -850mbar). It kinda ruined the response of the engine anything below 3000 which in a MT car is where you feel the initial urgency. However I was getting IAT of over 50C on the track after 3-4 laps so I needed the larger intercooler to make best use of the tune and give some consistency (power). It did the job and as the car (according to the AIM can device) is never below 2950 rpm at my local circuit the latency was not really noticeable.

The GTS I had for a few weeks was PDK. I think it benefits less from a smaller turbo in a sense. The manual you typically shift around 3500-400 from 1-2 from stationary each time. The PDK in normal mode seems to always shift a cog as soon as it can sometimes 3000 or below. To 60kmph the PDK in non sport mode had shifted to gear 5 or 6. In the Manual car I was just changing from 3 to 4.

The Giulia QV has bigger turbos and pulls all the way to the redline (7300) and still feels like its pulling then. It has a larger turbo installation, and some small latency in small throttle input form stationary. If you drive it in auto you will never run out of pull before it shifts but in race mode manual (basically all back road driving from me) the limitation is not the turbo size or the point of peak power but simply that you run out of revs so quickly.

Ive been through a few cars in the last 15 months including 718S PDK and 2017 Focus RS with Tune+ - most used on road and track.

If Porsche are going to use a larger turbo installation in the 3.0T Carrera range than the GTS/S unit they are already using (I forget the inlet size but maybe 52mm) then 7500 rpm limiter is not enough to get the full benefits IMO. They need to fortify the internals and allow a 8500 rpm limiter like the modern hi performance installations in the Maclaren 650S and 488. A bigger turbo needs rpm headroom and to get it reliably under thermal load on fast road and track the rest of the system may need revision (intercoolers, forged internals etc).

Thats just my opinion having spent a bit of time in the last year playing with different cars (including 650S).

P.S. Im not trying to make my Carrera a GT3 beater on track. I hope to own a 991.2 GT3 MT in the near future to fill that roll. I want a fun engaging back road and weekend car that needs to be worked to get pace out of it and that puts a smile on my face. hence the base Carrera choice in manual transmission. Its the only car in the current range (other than said GT3) that I found could come close to meeting this need. My GT4 was a disappointment because of the gearbox ratios, and the rear suspension was not as stable on the limit as multi-link installation on 911. Engine only revved to 7800 (not much more than 3.0T!).

dribar

So... if the 992 is supposed to be at the Paris Auto Show in October, when do you expect the configurator to be online with new pricing?
...and when will the dealers actually be able to order one for you (in the US)?

Just biding my time here.

Thanks.

subshooter

I've watched this process 10 times or so. It's usually the same day or the next morning from the public debut. You can usually order the car right away but the dealer likely wont have an allocation yet. You can submit a purchase order but the build date will be up in the air and the allocation is not guaranteed. If you get a commission number from the dealer, he has an allocation and it is in the system.

dribar

917k

rijowysock

i would A: go PDK (i liked how the MT was personable but it just lacked the oomph the PDK has, and maybe thats my fault/driving style too but "kickdown" on PDK makes the car faster than i ever could..
B: id install the chip kit, versus being lazy and having it sitting in drawer.. new owner chipped my 991.2 and said it's much *****'ier
C: i guess im just hopeful they make a better product versus worse. the 991.2 just felt slow, over refined and boring... id still say 997 GT3 is the best car porsche produces.

captainkirk

Your entire post is very insightful. I never realized on how the 991.2 Base Carrera with MT is a unique car. I have seen some videos mentioning 991.2 Base Carrera is one to really go for.

I can't wait for some more 992 tidbits to be released publicly. I want to know what improvements have been made. Always felt 991.2 is like a beta release (or more like soft launch) of the "mini" turbo engines in all. 992 will have the "more refined" turbo engines for all trims.

Michael T

Scorponok

Could not agree more!

gary.lee

I think 992 will be the last generation with ICE cars. The world will be all-electric in 5 to 10 years. You wont find a gas station. You can spam but you cant change the future. All the discussion about engine and exhaust sound will be pointless because there wont be an engine. It's called a electro-magnetic motor.