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    • Comparing Porsche 991.2 Carrera, S, and GTS 3.0 9A2 engine output and turbocharger sizes

      With the 991.2 GTS model Porsche is taking their 3.0 liter flat-6 to a stated 450 horsepower and 405 lb-ft of torque. What the GTS includes is larger turbochargers and new tuning compared to the standard 911 Carrera and Carrera S.


      The X51 package or Porsche Power Kit can be retrofitted by the dealer but only onto the S model. The 911 Carrera is left out in the cold for some reason (as many people would likely not buy the S if it was available) and the GTS of course has it standard.

      Let's take a look at the motors:

      9A2 3.0 991.2 Carrera


      Horsepower: 370
      Torque: 332 lb-ft
      Boost Pressure: 13.1 psi
      Bore x Stroke: 91mm x 76.4mm
      Redline: 7500 rpm
      Compression Ratio: 10.0:1
      Intercooler: Air to Air
      Turbos: 49mm compressor/45mm turbine

      9A2 3.0 991.2 Carrera S


      Horsepower: 420
      Torque: 369 lb-ft
      Boost Pressure: 16.0 psi
      Bore x Stroke: 91mm x 76.4mm
      Redline: 7500 rpm
      Compression Ratio: 10.0:1
      Intercooler: Air to Air
      Turbos: 51mm compressor/45mm turbine

      9A2 3.0 991.2 Carrera GTS

      Horsepower: 450
      Torque: 405 lb-ft
      Boost Pressure: 18.0 psi
      Bore x Stroke: 91mm x 76.4mm
      Redline: 7500 rpm
      Compression Ratio: 10.0:1
      Intercooler: Air to Air
      Turbos: 55mm compressor/48mm turbine

      Now, the engines are effectively all the same thing. Porsche is sharing parts and cutting costs. The only real difference is the turbocharger sizes, boost pressure, and tuning.

      The Carrera and Carrera S only differ by 2mm in turbo compressor size. The GTS however has a 6mm larger compressor and 3mm larger turbine.

      The difference on paper between the Carrera and S is supposed to be 50 horsepower:

      Carrera:


      Carrera S:


      It is roughly a 30 wheel horsepower difference which is not huge and easily mitigated and exceeded with minor modifications. The GTS will offer at least this much power and torque over the S. We do not have a dyno of one yet as it is not on the streets yet but expect over 400 horsepower to the wheels.

      If one is interested in power they should know that the base Carrera has the exact same engine internals as the other motors and can easily handle 450+ horsepower. Frankly, going to a set of hybrid turbos with larger wheels than the GTS will produce a lot more power at a fraction of the cost.

      How much more? We are going to have wait and find out.

      This article was originally published in forum thread: Comparing Porsche 991.2 Carrera, S, and GTS 3.0 9A2 engine output and turbocharger sizes started by Sticky View original post
      Comments 28 Comments
      1. Surquhar's Avatar
        Surquhar -
        Interesting, and I agree. When the ECU cracks and aftermarket turbos are available the base is the best bang for the buck. Any thoughts on why the couple of bench flash tuners that have advertised tunes are only offering S availability? Although maybe Vivid is pushing the GIAC tune, not sure.
      1. Sticky2's Avatar
        Sticky2 -
        Honestly, I think it's because they barely have any access. If they can do the S and not the base something is up. Plus I messaged GIAC saying hey flash me and crickets.
      1. Sticky2's Avatar
        Sticky2 -
        Vivid is pushing some piggyback btw.
      1. Surquhar's Avatar
        Surquhar -
        Click here to enlarge Originally Posted by Sticky2 Click here to enlarge
        Honestly, I think it's because they basically have any access. If they can do the S and not the base something is up. Plus I messaged GIAC saying hey flash me and crickets.
        It will be cool to hear what they come back with.
      1. Surquhar's Avatar
        Surquhar -
        Click here to enlarge Originally Posted by Sticky2 Click here to enlarge
        Vivid is pushing some piggyback btw.
        Wow I wonder who's been that involved with it? I hope we can flash these things from our driveways.
      1. Sticky2's Avatar
        Sticky2 -
        Click here to enlarge Originally Posted by Surquhar Click here to enlarge
        Wow I wonder who's been that involved with it? I hope we can flash these things from our driveways.
        Yeah some euro source. Regarding hand held flashing, Cobb is going to take a while.

        I'm hoping to provide a solution in the meantime.
      1. Surquhar's Avatar
        Surquhar -
        Click here to enlarge Originally Posted by Sticky2 Click here to enlarge
        Yeah some euro source. Regarding hand held flashing, Cobb is going to take a while.

        I'm hoping to provide a solution in the meantime.
        Awesome!!
      1. Surquhar's Avatar
        Surquhar -
        Click here to enlarge Originally Posted by Sticky2 Click here to enlarge
        Yeah some euro source. Regarding hand held flashing, Cobb is going to take a while.

        I'm hoping to provide a solution in the meantime.
        BTW has COBB given you any insight as to why they are going dark on updates? Is it because the code is tough to crack? I just don't think there are enough cars out there yet for them to attack it.
      1. Sticky2's Avatar
        Sticky2 -
        Click here to enlarge Originally Posted by Surquhar Click here to enlarge
        BTW has COBB given you any insight as to why they are going dark on updates? Is it because the code is tough to crack? I just don't think there are enough cars out there yet for them to attack it.
        It's the difficulty. I mean GIAC is even struggling with bench flashing.
      1. Bowser330's Avatar
        Bowser330 -
        Does the indentical bore, stroke and compression indicate the rods and pistons are exactly the same? Forged vs cast.....
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by Bowser330 Click here to enlarge
        Does the indentical bore, stroke and compression indicate the rods and pistons are exactly the same?
        Yes.

        Click here to enlarge Originally Posted by Bowser330 Click here to enlarge
        Forged vs cast.....
        I don't know what the internals are exactly. I'll look into it.
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by Bowser330 Click here to enlarge
        Does the indentical bore, stroke and compression indicate the rods and pistons are exactly the same? Forged vs cast.....
        Not easy to fine, so far all I have been able to dig up:

        Click here to enlarge Originally Posted by SAE Click here to enlarge
        The 3.0-L’s Continental-supplied, centrallylocated
        injectors are fed by two fuel pumps, one per cylinder bank,
        operating on a system pressure of up to 3626 psi (250 bar). Variable
        exhaust-camshaft timing facilitates precise control of the charge exchange
        process. On the intake side, Porsche’s VarioCam Plus adjusts
        both valve lift and opening duration.

        The 9A2 engine features plasma-coated cylinder bores, its iron
        content helping to reduce ring-to-bore friction, according to Porsche
        engineers. Overall mass reduction was a focus of the development
        program; the two turbochargers and their intercoolers and related
        plumbing added 77 lb (35 kg) to the 911’s powertrain, requiring extensive
        use of FEA to then remove 33 lb (15 kg). The crankcase uses a
        new design with thin-wall coolant galleries and different aluminum
        alloy to save 3.3 lb (1.5 kg). A reinforced-plastic oil pan replaced the
        old aluminum pan, saving 4.4 lb (2 kg). A new-design oil pump cuts
        2.6 lb (1.2 kg).

        The biggest single mass reduction is in the 911’s exhaust system:
        15.4 lb (7 kg). Reduced parasitics are addressed by the clutched water
        pump, which allows complete decoupling from the engine; this
        also helps the engine reach operating temperature faster. The A/C is
        also clutched.

        The new boxers’ power flows through a new dual-mass flywheel
        and twin-disc clutch
      1. Stevenh's Avatar
        Stevenh -
        Are you sure internals are identical in the base Carrera all the way through the GTS? I'm a little skeptic considering even the Macan GTS has different cams and pistons over the S.
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by Stevenh Click here to enlarge
        Are you sure internals are identical in the base Carrera all the way through the GTS? I'm a little skeptic considering even the Macan GTS has different cams and pistons over the S.
        Yes. The X51 package page states nothing of new internals, cams, heads, or anything else.

        It seems to be just turbos and tuning. Just like the S.
      1. Stevenh's Avatar
        Stevenh -
        Click here to enlarge Originally Posted by Sticky Click here to enlarge
        Yes. The X51 package page states nothing of new internals, cams, heads, or anything else.

        It seems to be just turbos and tuning. Just like the S.
        I really hope you're right, but Porsche knows these cars are going to be tuned and I think they're too smart to make it that easy. I'd love to buy a base Carrera, mod it and feel I'm missing out on nothing when compared to the guy who slapped some PURE turbos (hint hint) on his GTS.
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by Stevenh Click here to enlarge
        I really hope you're right, but Porsche knows these cars are going to be tuned and I think they're too smart to make it that easy.
        I think I am right but they ARE taking the tuning into account. The GTS has the biggest turbos so it will see the largest gains with a tune.

        A Carrera with a tune won't match the GTS with a tune. A Carrera with a tune won't match a Carrera S with a tune.

        They are maintaining the hierarchy still with the turbo sizing. It's deliberate. Actually, they even did this back with the 996 Turbo as the K16 turbos could not match the larger K24's that came with the X50 package or standard on the Turbo S (and GT2) tune only to tune only.

        Click here to enlarge Originally Posted by Stevenh Click here to enlarge
        I'd love to buy a base Carrera, mod it and feel I'm missing out on nothing when compared to the guy who slapped some PURE turbos (hint hint) on his GTS.
        Well that is the difference. The GTS and S cars that retrofit the X51 package essentially have a factory turbo upgrade.

        Once you go to Pure Turbos or other options, it doesn't matter if the car was a Carrera, S, or GTS for the starting point. Hence why I opted for the Carrera.
      1. Bowser330's Avatar
        Bowser330 -
        exciting times to come indeed....pure stage 2 turbos on the similarly sized BMW S55 engine are putting down 700whp+....
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by Bowser330 Click here to enlarge
        exciting times to come indeed....pure stage 2 turbos on the similarly sized BMW S55 engine are putting down 700whp+....
        700 rwhp is exactly my goal.
      1. Bowser330's Avatar
        Bowser330 -
        fueling has me concerned...I wonder what the limit will be on racegas...might need methanol to supplement and/or work with Fuel-it for another product offering...
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by Bowser330 Click here to enlarge
        fueling has me concerned...I wonder what the limit will be on racegas...might need methanol to supplement and/or work with Fuel-it for another product offering...
        Oh for sure, definitely.

        I'm concerned as well but have no idea what the fuel system limit is. For 700+ I'm definitely going to need meth or I don't know what.

        Maybe one of these BMW fueling companies will want to work with me.