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  • Hi Henry,

    Thanks for your questions.

    1. DCT transmissions are faster shifting than Manuals, plus drivers do not have to be proficient at "heel and toe" for smooth down shifting for corners. Also with DCT there is less weight transfer when shifting so better tire track contact resulting in faster lap times. Comparable tests tests have DCT cars faster than MT. The CCC decided to add 5 HI (1.5 PI), for these new generation auto transmissions.
    2. Looking at a lot of 135i dyno runs it appears hp between the two engines is very close, so we left it at 330 crank hp. BTW BMW kept the same 300 hp rating.
    https://www.google.com/search?sxsrf=ALeKk016fEtiRAE49
    3tDDmGh4AWkT5ocg:1609783745532&source=univ&tbm=isch&q=Dyno+BMW+2011+i135&sa=X&ved=2ahUKEwiP0MTi74LuA hVITd8KHV7lAM4QjJkEegQIAhAB&biw=1742&bih=850#imgrc=F1s0GT8MVQRISM

    A .4 PI or 1.1 PI won't much difference. If you are a newbie to track, then getting instruction and experience will be best gains you can make.

    JohnP

    Comment


    • Originally posted by John P View Post
      Hi Henry,

      Thanks for your questions.

      1. DCT transmissions are faster shifting than Manuals, plus drivers do not have to be proficient at "heel and toe" for smooth down shifting for corners. Also with DCT there is less weight transfer when shifting so better tire track contact resulting in faster lap times. Comparable tests tests have DCT cars faster than MT. The CCC decided to add 5 HI (1.5 PI), for these new generation auto transmissions.
      2. Looking at a lot of 135i dyno runs it appears hp between the two engines is very close, so we left it at 330 crank hp. BTW BMW kept the same 300 hp rating.
      https://www.google.com/search?sxsrf=ALeKk016fEtiRAE49
      3tDDmGh4AWkT5ocg:1609783745532&source=univ&tbm=isch&q=Dyno+BMW+2011+i135&sa=X&ved=2ahUKEwiP0MTi74LuA hVITd8KHV7lAM4QjJkEegQIAhAB&biw=1742&bih=850#imgrc=F1s0GT8MVQRISM

      A .4 PI or 1.1 PI won't much difference. If you are a newbie to track, then getting instruction and experience will be best gains you can make.

      JohnP
      Thanks for the explanation and the advise.

      I understand that no rating system is perfect but clearly some cars have a huge advantage like the BMW M-series, Porsche S & GTS , Chevy 1LE & Z51, etc. There is some irony here as I opted for the 135i instead of a M2.

      By ways of comparison:
      • an 135i with mild springs and springs has the same PI as a M2 in GT2 . M2 would still have better handling, LSD and more power
      • an 135i with M2-like mods would run in SGT1 with PI of 90.6 instead of GT2 with 77.9 PI. adding M2 turbos to 135 would bump it into modified.
      Last edited by Hqfoto; 01-07-2021, 09:20 AM.

      Comment


      • Hi Henry,

        Interesting comparison of 2011 135i with 7spd DTC to 2016 M2 with 7 spd DTC. Here is ccdb info;

        135i 3439 lbs, 330 Hp, 55 HI, 72.9 PI in GT2
        M2 3505 lbs, 386 Hp, 65 HI, 79.1 PI in GT1
        Custom ccdb Test mode of 135i with M2 engine/Hp, 3439 lbs, 386 Hp, 55 Hi, 76.5 PI in GT1

        So your 135i with 386 Hp (56 Hp more than stock 135i) would be 2.6 PI lower than M2. You could add LSD and still be 1.1 PI lower

        JohnP

        Comment


        • Originally posted by John P View Post
          Hi Henry,

          Interesting comparison of 2011 135i with 7spd DTC to 2016 M2 with 7 spd DTC. Here is ccdb info;

          135i 3439 lbs, 330 Hp, 55 HI, 72.9 PI in GT2
          M2 3505 lbs, 386 Hp, 65 HI, 79.1 PI in GT1
          Custom ccdb Test mode of 135i with M2 engine/Hp, 3439 lbs, 386 Hp, 55 Hi, 76.5 PI in GT1

          So your 135i with 386 Hp (56 Hp more than stock 135i) would be 2.6 PI lower than M2. You could add LSD and still be 1.1 PI lower

          JohnP
          I see where you are going with the prep points with the engine but respectfully, the 135i needs a lot of suspension work to keep up with the M2 on a road circuit.

          135i is a narrow body, parts bin car designed to use RFT (soft suspension & bushings to compensate for stiff tires). As such, it will need all 12 sPIP including points for control arms and protruding tires. But just taking 8sPiP for wheelwell, camber, shocks and springs would push me above 80 PI?

          EDIT: wouldn't the increased power be 6PiP ie. 3 for ECU and 3 for boost?

          Rulebook link is down so I can't verify.
          https://time-attack.ca/wp-content/up...-0.94-LIVE.pdf
          Last edited by Hqfoto; 01-17-2021, 12:42 AM.

          Comment


          • Hi Henry,

            Continuing with the hypothetical comparison, of M2 386 hp in your 135i. If a competitor was to take the suspension sPIPs suggested, here is what it would look like;

            Alignment (includes Control arms) 1 sPIP
            Shocks 2 sPIPs
            Springs/ride height 4 sPIPs
            Protruding wheels/flares 2 s PIPs

            Total is 9 sPIPs. Convert this to 7.1 PIPs using Conversion Chart on bottom of Rule Book page 40.

            So our hypothetical PI would be 76.5 + 7.1 = 83.6 in SGT3. Now if you use up all these Suspension points, would you put in a basic M2 Street suspension?

            Personally I would install the very best Coilovers, control arms and alignment plus wide wheels/flares I could afford.

            Maybe try going on the ccdb tool, to classify your proposed car with mods. You can run a number of scenarios to optimize. Once you Submit your Classification I will view it and provide extra comments.

            JohnP

            Comment


            • Hi OTA. Please add to the to the CCDB Base Car List:

              Subaru WRX, Sport, CVT (2019)

              Looking forward to returning to OTA for the 2021 season!

              Comment


              • Subaru WRX with CVT is in ccdb.

                JohnP

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