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    • Damn! The 2018 Porsche 911 (991.2) GT2 RS is really making 800 horsepower - 683 rwhp

      The new 991.2 generation 911 GT2 RS is the baddest 911 ever produced. It is the current Nurburgring champion. It's light with incredible grip and a ton of power. How much power? Well, Porsche rates the twin turbo 3.8 liter flat-6 at 700 horsepower.


      It's much, much higher than that. Excuse the garbage quality but the Dynojet figures state 683 horsepower and 580 lb-ft of torque at the wheels respectively:


      That is 803.5 horsepower at the crank folks if you go with the old school Dynojet 15% loss rule of thumb.

      The amazing thing is that the GT2 RS is still slightly short of the McLaren 720S but slightly ahead of the monster Corvette ZR1 rated at 755 horses.

      Those three cars make for the top current trio in the performance car world.

      This article was originally published in forum thread: Damn! The 2018 Porsche 911 (991.2) GT2 RS is really making 800 horsepower - 683 rwhp started by Sticky View original post
      Comments 39 Comments
      1. Arin@APR's Avatar
        Arin@APR -
        No way DTL is a percentage. The driveline didnít eat up over 100 hp.
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by Arin@APR Click here to enlarge
        No way DTL is a percentage. The driveline didn’t eat up over 100 hp.
        It's just a Dynojet rule of thumb used for context.

        The 911 is very efficient but losses aren't 2.5%.

        This thing is a monster.
      1. subaru335i's Avatar
        subaru335i -
        Click here to enlarge Originally Posted by Arin@APR Click here to enlarge
        No way DTL is a percentage. The driveline didn’t eat up over 100 hp.
        Yeah drivetrain loss is non linear based on speed and temp and power output, not a static % loss. Plus the Porsche transaxle is especially efficient without a prop shaft and no torque converter.

        I do think it is fair to say it is making a bit more than 700 at the crank though...
      1. pr3ci5n335i's Avatar
        pr3ci5n335i -
        Ugh, what I would do for one of these. Even though it's slightly under powered to the 720S, I'd still like to see them run.
      1. subaru335i's Avatar
        subaru335i -
        Click here to enlarge Originally Posted by pr3ci5n335i Click here to enlarge
        Ugh, what I would do for one of these. Even though it's slightly under powered to the 720S, I'd still like to see them run.
        Yeah I think the only deciding factor between the GT2 and the 720S is that the Mclaren will depreciate pretty badly as soon as the next hot one comes out and this GT2 will just keep going to the moon in value...its not fair.
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by pr3ci5n335i Click here to enlarge
        Even though it's slightly under powered to the 720S, I'd still like to see them run.
        The difference is small enough you could make it up with exhaust changes alone. However, the GT2 RS is in STD correction whereas our 720S is SAE.

        The 720S is no doubt more powerful but not by much.

        The GT2 RS would lose more due to its aerodynamics than anything else.
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by subaru335i Click here to enlarge
        and this GT2 will just keep going to the moon in value...its not fair.
        Will it? Past GT2's did not hold. Maybe this one will be the exception if it is the last one.
      1. subaru335i's Avatar
        subaru335i -
        Click here to enlarge Originally Posted by Sticky Click here to enlarge
        Will it? Past GT2's did not hold. Maybe this one will be the exception if it is the last one.
        I meant this GT2 RS and from a quick google it does appear that the 996 and 997 GT2 RS still go for crazy money.

        Even if they don't appreciate like crazy they certainly hold value better than any Mclaren short of the F1 and P1.
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by subaru335i Click here to enlarge
        I meant this GT2 RS and from a quick google it does appear that the 996 and 997 GT2 RS still go for crazy money.

        Even if they don't appreciate like crazy they certainly hold value better than any Mclaren short of the F1 and P1.
        There was no 996 GT2 RS unless my memory is failing me?
      1. turbo8765's Avatar
        turbo8765 -
        So the M5 is underrated. The GT2RS is underrated. The Benz’s are underrated. Either all the german cars are underrated or the dyno’s are simply calibrated to read high because that’s what the people want.

        Ockham’s razor.

        When the 2RS is put on the MAHA by SA it’ll make with 10hp of 700. Guaranteed.
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by turbo8765 Click here to enlarge
        So the M5 is underrated. The GT2RS is underrated. The Benz’s are underrated. Either all the german cars are underrated or the dyno’s are simply calibrated to read high because that’s what the people want.
        All the new turbo German cars are underrated.

        Click here to enlarge Originally Posted by turbo8765 Click here to enlarge
        When the 2RS is put on the MAHA by SA it’ll make with 10hp of 700. Guaranteed.
        The MAHA reads much more conservatively. That doesn't mean the GT2 RS isn't making a ton of power.

        My Carrera reads much lower on a MAHA than a Dynojet. So what?
      1. turbo8765's Avatar
        turbo8765 -
        The MAHA doesn’t read conervatively, it reads accurately. Germans are precise. They don’t rate power innacurately. We simply tell ourselves they do because it makes us feel better.

        Innacurate power ratings would defy EU law and open manufactueres to massive liabilty from consumers (particularly victims of crashes), insurance companies, and regulatory agencies to name a few.

        It simply is not the case.
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by turbo8765 Click here to enlarge
        The MAHA doesn’t read conervatively, it reads accurately.
        It's conservative compared to the Dynojet. MAHA does not determine what is accurate and neither do you.

        Click here to enlarge Originally Posted by turbo8765 Click here to enlarge
        Germans are precise.
        Then it's odd that suddenly their cars are making much more power than they did on these same dynos in the past.

        I'm sure turbos and a power war have nothing to do with it. They're trapping much higher at higher weights too because Germans just know how to get through the air better.

        Click here to enlarge Originally Posted by turbo8765 Click here to enlarge
        Innacurate power ratings would defy EU law and open manufactueres to massive liabilty from consumers (particularly victims of crashes), insurance companies, and regulatory agencies to name a few.
        No, they'll just claim the horsepower rating is the 'guaranteed' output even at elevation or when heat soaked or on poor fuel.

        Click here to enlarge Originally Posted by turbo8765 Click here to enlarge
        It simply is not the case.
        Unfortunately your opinion is not proof of anything. The Dynojet graph is however. As are the numbers the cars are putting down on the strip and in testing.

        You're wrong.
      1. subaru335i's Avatar
        subaru335i -
        Click here to enlarge Originally Posted by turbo8765 Click here to enlarge
        The MAHA doesn’t read conervatively, it reads accurately. Germans are precise. They don’t rate power innacurately. We simply tell ourselves they do because it makes us feel better.

        Innacurate power ratings would defy EU law and open manufactueres to massive liabilty from consumers (particularly victims of crashes), insurance companies, and regulatory agencies to name a few.

        It simply is not the case.
        A MAHA dyno is still a dyno and is flawed. It is calculating crank horsepower by measuring the drag lines when the clutch is in and transmission is in gear and then they basically measure steady state horsepower going up the revs by ramping suuuuper slowly.
        A MAHA run isn't what an engine does when you are racing unless you race from idle in top gear up a mountain.

        It is "precise" in that it takes into account the drag of the transmission and differentials but it is still back calculating a crank horsepower rating from a wheel horsepower test.

        It is still a chassis dyno and has the same disclaimer as any dyno sheet.
      1. SpeedLimit?'s Avatar
        SpeedLimit? -
        @Sticky , with Porsche pushing this motor so hard I think this is a great argument to back up your post about them using that new modular engine design to possibly build something bigger for new 911s...hybrid systems will be too heavy to outperform this!
      1. Stevenh's Avatar
        Stevenh -
        This isn't rocket science guys. Get a trap speed. Get the weight. Do some math. Argument over.
      1. Aces's Avatar
        Aces -
        DTL is probably closer to 10% given the engine sits on the axles.
        Either way thats still impressive power to the wheels.
      1. Sticky2's Avatar
        Sticky2 -
        Click here to enlarge Originally Posted by Aces Click here to enlarge
        DTL is probably closer to 10% given the engine sits on the axles.
        Either way thats still impressive power to the wheels.
        As stated losses aren't static. 15% is the traditional Dynojet correction factor for crank output.
      1. 93siro's Avatar
        93siro -
        Click here to enlarge Originally Posted by Sticky2 Click here to enlarge
        As stated losses aren't static. 15% is the traditional Dynojet correction factor for crank output.
        Traditional for front engine rear drive. For cars with transaxles and engine on top of it it was closer to 10%.
      1. Sticky2's Avatar
        Sticky2 -
        Click here to enlarge Originally Posted by 93siro Click here to enlarge
        Traditional for front engine rear drive. For cars with transaxles and engine on top of it it was closer to 10%.
        Ok, so what do you get with 10%?