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looking at dyno sheets

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    looking at dyno sheets

    I just thought of something.

    They say that on correctly scaled dyno sheets, the HP and TRQ lines always meet at 5252.

    What if you're dyno'ing a diesel engine or something that doesn't rev up to 5252? Do the lines never meet?

    Boggles my mind.
    R.I.P 07/01/09 - 04/23/10 :(

    #2
    never head of this... but if its true, i imagine that it only applied to gas engines.
    somhow i think this theory is wrong tho....

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      #3
      Originally posted by kowalski
      never head of this... but if its true, i imagine that it only applied to gas engines.
      somhow i think this theory is wrong tho....
      Its no theory. Horsepower is calculated by taking RPM x torque and dividing it by 5252.

      So HP = (RPM x Torque)/5252

      (5252 x torque)/5252 = torque, so torque and hp are equal at 5252 rpm on ANY engine.
      '91 318is
      sigpic

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        #4
        Originally posted by 92 mtechnic cabrio
        I just thought of something.

        They say that on correctly scaled dyno sheets, the HP and TRQ lines always meet at 5252.

        What if you're dyno'ing a diesel engine or something that doesn't rev up to 5252? Do the lines never meet?

        Boggles my mind.
        Yup, that's right...

        1995 Porsche 911
        1992 BMW 318ic
        2004 Volvo V70
        1988 M3 2.5L - gone
        1988 325is - gone

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          #5
          TO answer your question about diesel engines, you are correct that if the engine does not rev to 5252rpm, the TQ + HP lines will not meet.


          Bret.

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            #6
            Originally posted by Brew
            Its no theory. Horsepower is calculated by taking RPM x torque and dividing it by 5252.

            So HP = (RPM x Torque)/5252

            (5252 x torque)/5252 = torque, so torque and hp are equal at 5252 rpm on ANY engine.
            Yup, what brew said. They are just functions of each other.

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              #7
              is there any kind of formula to figure out hp at the wheels on E30? with milage (156k)? I searched but all I found was hp at the crank... I know that all the maintance shit has to add up to, but I've done most of the things on my thirty.
              sigpic

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                #8
                just do something like 15% of the crank hp, to accomodate for power lost through the drivetrain

                so a brand new, stock E30, would do 142.8hp at the wheels. (168*0.15= 25.2, 168-25.2= 142.8)

                a car similar to mine, stock with the exception of 19lb injectors, put down 140whp at around 120k miles.
                R.I.P 07/01/09 - 04/23/10 :(

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