OFFICIAL 991.2 GT3 RELEASE *Confirmed 500HP 4.0 & Manual option*
#1021
Rennlist Member
Originally Posted by RajDatta
No sure I would agree. Motorsports engines get the best of the best and the .2 engines is based on the R and RSR engines. That to me tells me it is a more robust engine with racing pedigree. It's irrelevant if they can amortize the cost by using this new engine in motorsports as well as street cars. Expensive is not always better.
#1022
Race Director
Thread Starter
Didn't mean to start an R discussion with the video. Just thought it was cool to see a candid amateur video.
Would rather discuss options and info on the .2 GT3 here rather than compare it with other models, discuss pricing, allocations, values, worthiness of ownership, and all other subjects we already have threads for those things.
Would rather discuss options and info on the .2 GT3 here rather than compare it with other models, discuss pricing, allocations, values, worthiness of ownership, and all other subjects we already have threads for those things.
Last edited by STG; 03-11-2017 at 04:01 PM.
#1023
Rennlist Member
There is not. AP says in the introductory DriveTribe video that the SMFW will end up damaging the bearings when mated to this engine.
#1024
Nordschleife Master
A lot of performance cars, in fact I believe the vast majority of modern performance cars come with hydraulic valve train motors including the previous generation GT3’s with the Mezgers. It was only in race application that PAG used solid lifters historically. Other examples of hydraulic valved performance street track cars… all 997’s, all 991’s., GT4, all Boxster’s and Caymans, Ferraris back to the late 355s, Corvettes, Lambo’s, Mac’s, R8’s, AMG GT and AMG GTR, Vipers, M3’s and M4’s, GT350s, :’17 Mustang GT4, Boss 302 (‘12& ’13) including the R and S.
As you increase engine rpm limits or require higher rpm limits hydraulic valve trains reach their limitations. This is because under the stresses of high rpm, the hydraulic piston, which serves to zero-out the clearances in normal operation, can either pump up or bleed down.
Solid lifters are as the name implies-solid. There is no internal mechanism to take up clearance, and in fact, they require clearance to operate properly. This clearance is called the valve lash. As the cam comes around to the base circle, the lifter must unload the valvetrain and allow the valve to close. This occurs at zero lash, but some additional clearance is needed to give the solid-lifter valvetrain a little wiggle room to compensate for dimensional changes due to heat expansion. Lash is adjusted with wear or as setting fall out of adjustment. However, as RPMs rise so does valve spring pressure requirements leading to potential wear.
Go to minute 4:13.
It's not that solid lifter engines are "better". They are capable of reaching higher rpms due to lack of hydraulic issues but on the down side require higher pressure springs to compensate for the higher rpms leading to potential earlier wear.
The current .2 GT3 4.0L puts out the same performance power specs as the .1 4.0L with a 400 rpm higher red line. In my mind not that much difference.
They were running the GT3R in 2015 with the street RS motor beginning in 2015. This from PAG web site:
Powering the new 911 GT3 R is a cutting-edge four-litre flat-six unit which is largely identical to the high-performance production engine of the road-legal 911 GT3 RS. Direct petrol injection, which operates at pressures up to 200 bar, as well as variable valve timing technology ensure a particularly efficient use of fuel. Moreover, the normally-aspirated engine offers significantly better driveability and a broader usable rev range. Power from the rear engine is transferred to the 310 mm rear wheels via a Porsche sequential six-speed constant-mesh gearbox. As in the GT road-going models of the 911, the driver changes gears via shift paddles conveniently positioned on the steering wheel.
Engine:
◾Water-cooled six-cylinder boxer engine (rear mounted)
◾4,000 cm3; stroke 81.5 mm; bore 102 mm
◾Output: over 368 kW (500 hp) subject to FIA BoP (air restrictor)
◾Four-valve technology
◾Direct fuel injection
◾Dry sump lubrication
Also, ths from Car & Driver in 2015:
Just like its predecessor, the GT3 R is again powered by a 4.0-liter flat-six engine shared with a production model. In this case, the engine donor is the epic 911 GT3 RS, meaning the GT3 R gets direct fuel injection, dry-sump lubrication, and at least 500 horsepower. That muscle is routed to the rear wheels via a six-speed sequential transmission and a mechanical limited-slip differential, and racing-specific anti-lock braking and traction-control systems help keep things in check.
This from Autoweek May 2015.
We suspect the naturally aspirated 4.0-liter six-cylinder boxer engine out back, good for “over” 500 hp, sounds glorious as well. It’s the same motor you’ll find in the 911 GT3 RS. There’s no manual option -- just a sequential six-speed constant-mesh gearbox -- but we can’t complain, for once, because shaving fractions of seconds off lap times is this car’s raison d’tre. Power is channeled to the rear wheels through a mechanical limited-slip differentia.
Read more: http://autoweek.com/article/car-news...#ixzz4b30WhN9n
So it appears that the hydrraulic lump did see competition and it would appear that PAG switched at some point to solid tappets used in the RSR for the Gen 2 "G" openning the door to even higher rpms in the future as the .2 now reves to 9000 where as the 2015 GT3R red lined at 8500 rpm and the current GT3R and Cup still interestingly red line at 8500 rpm. Perhaps PAG feels that they can get away with stiffer springs on the street version due to the fact they likely will not be seeing the constant and extended higher rpms of the race versions thus the stiffer springs are not an issue with premature wear.
Further, and importantly hydraulic valued motorsport heritage for the 9A1 DFI engines is also established by the GT4 Club sports which use the 991S 3.8L lump now competing in the Continenntal Sports car series in GTS. Our own CJ Wilson is campaigning a pair of GT4s.
Last edited by Waxer; 03-12-2017 at 09:08 AM.
#1026
Drifting
Beyond the name-plate LE (which is a biggin) LWFW is the 800lb gorilla in the room difference not being discussed much. My past experience is that it was a game changer between 997 models that had DMFW and LWFW. could easily be upgraded in most of the 997s. Sounds like not an option in 991.2-3. That's too bad.
#1029
Addict
Rennlist Member
Rennlist Member
#1030
As another note, at least since last year the Cayman/Boxster carry different versions of the 4-way sports seats plus. So if you are at the dealer you can't use that as a reference.
#1031
Rennlist Member
Beyond the name-plate LE (which is a biggin) LWFW is the 800lb gorilla in the room difference not being discussed much. My past experience is that it was a game changer between 997 models that had DMFW and LWFW. could easily be upgraded in most of the 997s. Sounds like not an option in 991.2-3. That's too bad.
#1032
Rennlist Member
^ AP is a salesman. What he actually said to PH was, "So the new engine with the single-mass flywheel up to this point in time is not possible."
I'm sure we will see it eventually, either on this or another model...
I'm sure we will see it eventually, either on this or another model...
#1033
#1034
Rennlist Member
^ My money is on the former; perhaps on a Speedster version as well. I do think the RS will remain PDK.
#1035
Rennlist Member
And what he then said in the Drivetride video was that "the engine was so responsive and snappy that you won't miss it".