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    • The limit of the Porsche 991 Turbo direct injected fuel system is ~650 awhp

      It looks like we finally have a concrete answer as to the Porsche 991 Turbo and 991 Turbo S fuel system capability. A Rob Tuned car using the Cobb Accessport found the limit at 19 psi. With modified VTG turbochargers, upgraded exhaust, intake, and associated bolt ons it hit 657 all wheel horsepower.


      When pushed to 21 psi of boost 675 horsepower at all four wheels was achieved but the fuel pressure dropped signalling the stock fuel system limits.

      For those wondering how this fuel system limit is being circumvented by the more powerful 991 Turbos out there it is all about methanol injection for supplemental fuel. That is the solution employed by ES Motor for example.

      We will have to wait and see who upgrades the stock fuel system to support more but for now methanol seems to be the only option for 991 Turbo and S owners who want to go beyond the 650 wheel horsepower mark.


      This article was originally published in forum thread: The limit of the Porsche 991 Turbo direct injected fuel system is ~650 awhp started by Sticky View original post
      Comments 12 Comments
      1. Flinchy's Avatar
        Flinchy -
        LPFP limits or HPFP?
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by Flinchy Click here to enlarge
        LPFP limits or HPFP?
        I don't know, maybe the injectors but I doubt it.
      1. Spool's Avatar
        Spool -
        Ekanoo 991tt 650 kit just set new record with 9.5@146.x mph
        that kind of trap speed only from 650hp?
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by Spool Click here to enlarge
        Ekanoo 991tt 650 kit just set new record with 9.5@146.x mph
        that kind of trap speed only from 650hp?
        It's obviously way more power.
      1. Spool's Avatar
        Spool -
      1. Emre@Esmotor's Avatar
        Emre@Esmotor -
        Hello guys,

        This car has our VTG upgrade and this car also has Aquamist HFS4 methanol kit.
        I don't know why they are out of fuel. Maybe fuel pump is not working well.. We dont spray tons of methanol with extra nozzles etc, we run them as they designed to run from their box.

        BTW, I checked the logs on the 9.59 run, we still have enough fuel. I think the car can make 9.4x with same setup and tune.

        Weather was around 33c (92F) and trap speed was not ideal 1.44sec. (best was 1.35s)

        Cheers
        Emre
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by Emre@Esmotor Click here to enlarge
        Hello guys,

        This car has our VTG upgrade and this car also has Aquamist HFS4 methanol kit.
        I don't know why they are out of fuel. Maybe fuel pump is not working well.. We dont spray tons of methanol with extra nozzles etc, we run them as they designed to run from their box.

        BTW, I checked the logs on the 9.59 run, we still have enough fuel. I think the car can make 9.4x with same setup and tune.

        Weather was around 33c (92F) and trap speed was not ideal 1.44sec. (best was 1.35s)

        Cheers
        Emre
        What is the limit of the stock fuel system then? It seems like they definitively found the limit without any supplemental fuel.
      1. Emre@Esmotor's Avatar
        Emre@Esmotor -
        Sorry for my wrong explanation.

        The car in this thread, that has the dyno sheet, has meth injection, but i dont know the problem on that car to be honest.

        Direct injection require different tuning strategy, thats maybe why they hit fueling limit earlier.

        I have a few more new things to try on my own car (991tts),
        new things coming on 991 platform, built engine, stand alone ecu, new heads and intake manifold with additional injectors...

        I hope to clarify the factory fueling and pdk limits very soon Click here to enlarge
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by Emre@Esmotor Click here to enlarge
        Sorry for my wrong explanation.

        The car in this thread, that has the dyno sheet, has meth injection, but i dont know the problem on that car to be honest.

        Direct injection require different tuning strategy, thats maybe why they hit fueling limit earlier.

        I have a few more new things to try on my own car (991tts),
        new things coming on 991 platform, built engine, stand alone ecu, new heads and intake manifold with additional injectors...

        I hope to clarify the factory fueling and pdk limits very soon Click here to enlarge
        That's right, he said the car with meth injection can do more. In this pull it was on the direct injection factory fuel system from what he wrote.

        With meth, he can do much, much more.
      1. Emre@Esmotor's Avatar
        Emre@Esmotor -
        Click here to enlarge Originally Posted by Sticky Click here to enlarge
        That's right, he said the car with meth injection can do more. In this pull it was on the direct injection factory fuel system from what he wrote.

        With meth, he can do much, much more.
        He was spraying meth on that run. That wasnt a pure race gas pull. I'm %100 sure. Click here to enlarge
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by Emre@Esmotor Click here to enlarge
        He was spraying meth on that run. That wasnt a pure race gas pull. I'm %100 sure. Click here to enlarge
        Ok you likely know better. I was just going by what he said.

        Anyway, would definitely like more details on the fuel system limits when you find them.
      1. 918 spyder's Avatar
        918 spyder -
        The 991 loves meth! We maxed out the setting at 6 and gained 30hp on the dyno. Additionally, we added dedicated fuel to go along with the 70 shot of nitrous to achieve roughly 700 hp. However we are not even close on 1/4 mile times. I'm not sure how this is possible but would like input. To achieve a 9.5 you have to have more hp then 700!